HEADQUARTERS
U.S. Army Information Systems Engineering Command
Fort Huachuca, Arizona 85613-5300
Automated Information Systems (AIS)
Design Guidance
Terrestrial Systems
Upated, 26 Aug 98
TABLE OF CONTENTS
2. DEPARTMENT OF DEFENSE (DoD) AND INDUSTRY SYSTEMS DESIGN GUIDANCE
2.1 Department of Defense (DoD) Standards
2.1.1 Technical Architecture Framework for Information Management (TAFIM)
2.1.2 Joint Technical Architecture (JTA)
2.1.3 Defense Information Infrastructure (DII) Master Plan
2.1.4 Defense Information Infrastructure (DII) Common Operating Environment (COE)
2.1.5 DoD Directives (DoDD) and Instructions (DoDI)
2.1.6 Chairman of the Joint Chiefs of Staff Instruction (CJCSI)
2.1.7 Defense Information System Agency (DISA)2.2 Industry Architectural Standards Applicable to Terrestrial Systems
3. U.S. ARMY SYSTEMS DESIGN GUIDANCE
3.1 Office of Director of Information Systems for Command, Control, Communications, and Computers (ODISC4)
3.2 Joint Technical Architecture-Army (JTA-Army)
3.3 U.S. Army Communications Electronic Command (USACECOM)
4. DESIGN GUIDANCE AND ENGINEERING EXAMPLES
4.1.1 Minimum Essential Requirements
4.1.2 Architecture
4.1.2.1 Fiber Networks
4.1.3 Migration Strategy
4.1.3.1 User Access
4.1.3.2 Service Support
4.1.4 Legacy Systems
4.1.5 System Design Guidance
4.1.5.1 FO Design Standards and Directives
4.1.5.2 Interfaces
4.1.5.2.1 Asynchronous Transfer Mode (ATM) Physical Layer Interface
4.1.5.2.2 Network Node Interface (NNI)
4.1.5.3 Performance and Design Considerations
4.1.5.4 Procurement Sources for Hardware and Software Information
4.1.5.4.1 Fiber Optic Equipment Vendors
4.1.5.4.2 Fiber Optic Cable Type
4.1.5.4.3 Fiber Optic Cable Size
4.1.5.4.4 SONET Hardware
4.1.6 Engineering Guidance
4.1.6.1 FO System Engineering Development Tools
4.1.6.2 FO System Security Consideration4.2.1 Minimum Essential Requirements
4.2.2 Architecture
4.2.3 Migration Strategy
4.2.4 Legacy Systems
4.2.5 System Design Guidance
4.2.5.1 Procurement Source for Hardware and Software
4.2.6 Engineering Guidance
4.2.6.1 HF System Engineering Development Tools
4.2.6.2 HF System Security Consideration4.3 Microwave (mw) Line of Sight (LOS) Radio Systems
4.3.1 Minimum Essential Requirements
4.3.2 Architecture
4.3.3 Migration Strategy
4.3.3.1 Korean Digital Microwave Upgrade (DMU)
4.3.4 Legacy Systems
4.3.5 System Design Guidance
4.3.5.1 Traffic Routing Planning
4.3.5.2 Path Profile and Link Analysis
4.3.5.3 Diversity and Protection Schemes
4.3.5.4 Procurement Sources for Hardware and Software
4.3.6 Engineering Guidance
4.3.6.1 Microwave System Engineering Development Tools
4.3.6.2 Microwave System Security Consideration4.4.1 Minimum Essential Requirements
4.4.2 Migration Strategy
4.4.3 Legacy Systems
4.4.4 System Design Guidance
4.4.4.1 Procurement Source for Hardware and Software
4.4.5 Engineering Guidance
4.4.5.1 Trunked Radio System Engineering Development Tools
4.4.5.2 Trunked Radio System Security Consideration4.5 Copper Cable (Coaxial and Twisted Pair) Systems
4.5.1 Minimum Essential Requirements
4.5.2 Migration Strategy
4.5.2.1 Beyond Category 5
4.5.3 Legacy Systems
4.5.4 System Design Guidance
4.5.4.1 Procurement Source for Hardware and Software
4.5.5 Engineering Guidance
4.5.5.1 Copper Cable System Engineering Development Tools
4.5.5.2 Copper Cable System Security Consideration4.6 Personal Communications Systems
4.6.1 Minimum Essential Requirements
4.6.2 Architecture
4.6.3 Migration Strategy
4.6.4 Legacy Systems
4.6.4.1 Procurement Sources for Hardware and Software
4.6.5 Engineering Guidance
4.6.5.1 Digital PCS Security Consideration
4.6.5.2 Wireless Network Technologies
4.6.5.3 Personal Messenger Wireless Modem Applications
4.6.5.4 Wireless Communications Test Support
4.6.5.5 PCS Engineering Development Tools
The purpose of this Terrestrial Design Guide is to provide broad based technical guidance for Commanders, Managers and Systems Engineers who are responsible for the implementation of United States (U.S.) Army Terrestrial Communications Systems and the integration of those systems into the overall U.S. Army Automated Information Systems (AIS). The technical guidance provided in this document is intended to furnish engineering, integration, interfacing, and implementation guidance that will become the basis for development of more detailed system design plans (SDPs), engineering installation packages (EIPs), test plans (TPs), and test reports (TRs) for specific Army implementation application. These systems include fiber optic (FO), high frequency (HF), microwave (mw) line of sight (LOS), trunked radio, copper cable, and personal communications system (PCS).
This design guide is intended to be a living document and will be reviewed for applicability on a periodic basis to keep current with changes to established architectures and significant advances in the state of art for terrestrial systems. The United States Army Information Systems Engineering Command (USAISEC) Point of Contact (POC) for all Terrestrial Systems is Mr. Troy Roberts. DSN: 879-3089; e-mail: RobertsT@emh1.hqisec.army.mil
The terrestrial based military information system is currently undergoing a massive insertion of new technology. This insertion is being driven by the user's constant and insatiable appetite for higher bandwidth communications to support enhanced multimedia data and joint collaboration tools. The role of terrestrial systems (i.e., FO, HF, mw, trunked, copper cable, and PCS) is constantly being challenged to meet these continuing demands.
The new technology that enable this revolution in capability is being made available by commercial developed technologies that will provide higher bandwidth, enhanced efficiency, and the convergence of data, voice, and video. The following subparagraphs provide a brief overview of the technologies discussed in this design guide.
The goal of this document is to provide engineers responsible for implementing the design of Army terrestrial systems with information on policies, standards, design constraints, migration strategy, and target architectures. The purpose of this design guide is to provide the maximum guidance in the implementation of military terrestrial systems where appropriated to the user and engineering design.
This document provides technical guidance for the engineering and design of terrestrial systems (i.e., FO, HF, mw, trunked, copper cable, and PCS), and also identifies the media standards, policies, and directives applicable to each. These standards, policies, and directives provide the design guidance for telecommunication system engineers and must be carefully reviewed and evaluated so that appropriate engineering practices and procedures are applied. This design guide identifies new and emerging technologies which can be used to assist in the design and engineering of terrestrial systems. This document is intended to be used as a primary point of reference for the design and engineering of terrestrial systems within the Army.
The Installation Information Transfer System (IITS) Design Guidance and IITS Policy and Technical Application documents provide detailed lists and appropriate applicability of those standards that apply to new installations and to major upgrades.
An evolving list of standards and references, including brief abstracts of many of the standards, is available from the Defense Information Systems Agency (DISA) Joint Interoperability Engineering Organization (JIEO) Center for Standards-Information Technology Standards Document library.
The information systems within the military are undergoing unprecedented transformation. To meet the demands of the current technology insertion, brought about by the users' demands for faster services and greater bandwidth, design standards, policies, and directives are being promulgated to meet the communication challenges of the future. The following subparagraphs will discuss listed standards and policy documents and responsible organizations at the DoD level, and will identify their impact on current and future terrestrial system designs. The following paragraphs will also provide the purpose of each document and discuss the actions required by the design guide to comply with the document. The cited documents provide the design guidance for attaining the target architecture and must be reviewed and evaluated so that appropriate areas are applied.
The Official TAFIM Policy states: "The TAFIM is intended to guide the development of architectures that satisfy requirements across missions, functional areas, and functional activities. The TAFIM is mandatory for use in DOD. The specific technical architectures for missions and functions will be developed using standard architecture guidance and development methodologies provided by the TAFIM."
While the TAFIM is not intended to provide detailed engineering guidance in the development of engineering solutions, it does provide the high level architectural guidance for which to all engineering solution should flow. The TAFIM applies to many DoD mission/domain areas and lists all adopted information technology standards that promote interoperability, portability, and scalability. Technical Architectures, such as the DoD Joint Technical Architecture (JTA) draws on the TAFIM, which documents the processes and framework for defining the JTA and other technical architectures.
For these reasons all ISEC systems engineers should have reviewed and be aware of the directions given in the TAFIM before proposing any solutions.
The Army Science Board (ASB) defines a Technical Architecture as "a minimal set of rules (e.g., protocols, standards, interfaces) governing the arrangement, interaction, and interdependence of the parts or elements that together may be used to form an information system". The JTA applies this definition by providing common set of mandatory information technology standards and guidelines to be used in all new and upgraded systems across DoD. The scope of the JTA is focused on Command, Control, Communications, Computers, and Intelligence (C4I) systems (to include sustaining base systems, combat support information systems, and office automation systems).
The JTA is a forward-looking document, defining the standards by which to build new and upgrade existing systems. The intent is to indicate migration direction. Existing systems are not expected to conform immediately to the JTA. When these systems are upgraded, the JTA will be used to transition the system toward a common interoperability goal. The standards in the JTA are almost entirely performance-based interface standards. Most are commercial standards.
DoD engineers and managers must be very familiar with the standards mandated in the JTA. Throughout the remainder of this Design Guide, and specifically the detailed engineering guidance presented in section four, the JTA standards that apply to transmission systems will be elaborated and guidance suggested on how these can be applied to specific engineering solutions.
The following sub-sections detail the JTA standards that are applicable to Terrestrial Communication Systems:
The DII Master Plan is a tool used to manage the evolution of the DII. The descriptive and analytical data for the DII will be available at several levels of detail. The purposes of the DII Master Plan are to:
The DII COE details the technical and functional requirements for a common operating environment of information support to the Warfighter. It identifies classes of functions common to all or most application components. The development of the DII COE stems from the Global Command and Control System (GCCS) COE effort and is perhaps the most significant and useful technical by-product of the GCCS development effort. As an outgrowth of this effort, the Services have agreed to migrate their Command and Control (C2) systems to the DII COE.
Although at first look the DII COE specifications appear to have little impact on transmission systems, it should be noted that the integration of new automated transmission systems rely heavily on computer Human Factors Engineering issues that the DII COE will impact. The most pronounced of these it the integration of Network and Systems Management issues.
DoDD 4630.5, "Compatibility, Interoperability, and Integration of Command, Control, Communications, and Intelligence (C3I) Systems." Promulgates policy for compatibility, interoperability, and integration of C3I systems used in the DoD.
DoDI 4630.8, "Procedures for Compatibility, Interoperability, and Integration of Command, Control, Communications, and Intelligence (C3I) Systems." Implements the policy in DoDD 4630.5, and assigns responsibilities and prescribes procedures to achieve compatibility and interoperability of a consolidated, DoD-wide, global C3I infrastructure.
Chairman of the Joint Chiefs of Staff Instruction (CJCSI) 6212.01A, "Compatibility, Interoperability, and Integration of Command, Control, Communications, Computers, and Intelligence Systems." Implements the policy established in DoDD 4630.5 and DoDI 4630.8, supports the C4I for the warrior (C4IFTW) initiative, and makes the Military Communications-Electronics Board (MCEB) the focal point for enforcement of the policy.
The DISA core mission includes the Defense Information Systems Network (DISN), GCCS, and Defense Message System (DMS). The mission is "to plan, engineer, develop, test, manage programs, acquire, implement, operate, and maintain information systems for C4I and mission support under all conditions of peace and war". DISA is the DoD agency responsible for information technology.
The area of concern for this guide is the DISN portion of DISA's mission that relates to long-haul terrestrial systems. Army and ISEC engineers designing long haul transmission systems must realize that all of the systems that are being developed are either a part of the DISN or act as an extension to the DISN. In order to obtain the greatest amount of interoperability for DoD architectures Army engineers must therefore tack the direction and interfaces of the DISN to insure a seamless integrated architecture.
The DISN is the DoD consolidated worldwide, enterprise-level telecommunications infrastructure that provides the end-to-end information transfer network for supporting military operations, national defense C3I requirements, and corporate defense requirements. DISN is the communication transport piece of the DII, which is of a widely distributed, user-driven infrastructure into which the Warfighter can gain access from any location for all required information. The DISN is structured to satisfy requirements that are evolving in response to changing military strategy, changing threat conditions, and advances in information and communications technology. DISN provides the transmission and switching of voice, data, video, and point-to-point bandwidth services for long-haul networks that are supported by the terrestrial systems addressed in this design guide. (Select here to link to a list of available DISN documents.)
The DISN, as described in CJCSI 6211.02(3), dated 23 June 1993, Defense Information System Network and Connected Systems, includes point-to-point transmission, switched data services, video teleconferencing, etc. The CJCSI directs all Services/Agencies (S/A) to submit all long-haul communication requirements to DISA for provisioning on the DISN.
The goal of DISN architecture is to facilitate a graceful technological evolution from the use of networks and systems that are owned and operated by the DoD to the use of commodity services wherever possible. A possible source of these commodity services may be the Federal Telecommunications System-2000 (FTS-2000) and its replacement, the Post-FTS-2000 (PF2K), based upon service availability, satisfaction of operational and technical requirements, and cost.
The DISA Transition Team has the responsibility to manage the transition of all DoD customers to the new DISN. DISA's goal is to transition or cut over all DoD customers with minimal impact to their operational effectiveness. To achieve this goal, extensive cutover planning and coordination with DoD customers is required. DISN will provide service to over 500 bases, posts, camps, and stations across the continental United States. At each of those locations, a local area coordinator (LAC) will be assigned to provide coordination to cut over facilities under their cognizance. LACs will provide critical technical information available only at the local level that will enable cutover activities to be planned and executed. They will also serve as the local POCs for site survey visits and any other activities involving their location. The knowledge and assistance provided by LACs is a key ingredient in the successful transition to DISN.
A detailed listing of information transfer mandated standards and internet links to these standards is identified in Appendix B, of the JTA-Army. These standards are required for interoperability between and among systems, supporting access for data, facsimile, video, imagery, and multimedia systems. Also identified are the standards for internetworking between different subnetworks and transmission media standards for SONET and radio links. These standards promote seamless communications and information transfer interoperability for DoD systems.
This section provides a general reference for applicable DoD and industry standards, architecture, and systems that define the context for AIS (i.e., terrestrial systems). A short summary paragraph is provided for each with the appropriate hot link uniform resource locator (URL) provided for additional detail if available. This section is primarily provided for reference and definition purposes.
The ODISC4 was directed to develop and implement the JTA-Army by the Army Enterprise Implementation Plan. The purpose of a technical architecture is to ensure that systems conform to a specified set of requirements.
The JTA-Army defines a technical architecture as "a minimal set of rules governing the arrangement, interaction, and interdependence of the parts or elements that together may be used to form an information system".
The JTA-A is the Army's direct extension to the JTA. It provides the the technical baseline for Army systems design guidance. It simplifies the DoD TAFIM in some ways by condensing the guidance, which is stated within the TAFIM in broad terms to encompass the entire DoD as an enterprise system, to Army-specific requirements. Its purpose is to ensure that Army system development (and the migration of existing information systems) satisfies a specified set of requirements that lead to interoperability. The JTA-Army can be compared to a building code. That is, it does not tell the engineer what to build or how to build; it delineates the standards that will have to be met to pass inspection before the system can be used. Also, like building codes, the JTA-Army is a constantly evolving set of guidelines. As technologies and standards change, so will the JTA-Army. It will not remain static but will evolve through participation with DoD, industry, and international standards organizations in order to identify trends and standards.
Based on a policy memorandum dated 29 June 1994, wherein the Secretary of Defense stated his commitment to "a new way of doing business" in DoD to include the use of open systems, the JTA-Army is heavily oriented toward the use of open systems standards. The JTA-Army takes advantage of commercial investment in information technologies. The sections of the JTA-Army that most apply to long-haul transmission systems are primarily the communication transport standards and architecture.
As with the JTA, Army engineers and managers must be very familiar with the standards mandated in the JTA-Army. Throughout the remainder of this Design Guide, and specifically the detailed engineering guidance presented in section four, the JTA-Army standards that apply to transmission systems will be elaborated and guidance suggested on how these can be applied to specific engineering solutions.
The following sub-sections detail the JTA-Army standards that are applicable to Terrestrial Communication Systems:
The USACECOM mission is to research, develop, acquire, field and sustain technologically superior and integrated Communication, Command, Control, Computer, Intelligence, Electronic Warfare and Sensors (C4IEWS) capabilities for America's Warfighter. USACECOM provides the architectural framework and systems engineering to insure joint interoperability and horizontal technology integration across the battlespace. USACECOM executes its mission throughout the lifecycle of warfighting systems and platforms through an integrated process of technology generation and application, acquisition excellence, and logistics power projection.
The AMC has assigned the USACECOM as the AMC EA-IM. The vision of the AMC EA-IM for corporate information is to provide an information systems architecture that will allow AMC to achieve seamless, interoperable information management (IM) solutions that are compliant with established Army and DoD standards, policies, and programs. The EA-IM mission is to provide a global information systems architecture which will allow AMC to develop and deploy integrated and seamless information systems which maximize new technologies and support economies of scale to better support the soldier. The AMC EA-IM mission also includes providing AMC with corporate information systems policy advice and technical guidance. The EA-IM will assess systems interoperability, integration, and technologies. It will provide technical consultation to major subordinate commands (MSC), separate reporting activities (SRA), Deputy Chiefs of Staff, Information Management (DCSIM), Directors of Information Management (DOIM), and their subordinate elements to assure interoperability between information systems deployed throughout the AMC and assist in the synchronization of the major programs fielded at AMC facilities. The EA-IM will posture the AMC to accurately and rapidly manage its corporate information systems to equip and project the nation's power worldwide and sustain soldiers when deployed.
USAISEC has been assigned the lead operational element within USACECOM for implementing the procedures for and insuring that all AMC engineered products adhere to architectural standards and are synchronized, integrated, and interoperable. This responsibility includes the development and maintenance of USAISEC Technical Guides and associated checklists that serve as architectural standards. These guides are based, in part, upon the policies, standards, and guidance promulgated by the various levels of DoD organizations discussed above.
The following subparagraphs will provide more detailed integration and engineering guidance for the engineer or person responsible for designing a terrestrial system. This section will present target architectures, migration strategies, and engineering guidance for attaining the target architecture and design. The guidance will discuss legacy systems, interface requirements, emerging technologies, and their impact on the evolution of terrestrial systems. The discussion will include some comparisons of terrestrial systems.
Fiber optics are fibers of glass, usually about 120 micrometres in diameter, which are used to carry signals in the form of pulses of light over distances up to 50 kilometers (km) without the need for repeaters. These signals may be coded voice communications or computer data. Two main light sources are used in the field of fiber optics: light emitting diodes (LEDs) which are typically used with multi-mode fiber and laser diodes (LDs) which are typically used with single-mode fiber.
Figure 1: Planar LED.
Figure 1: Detailed Planar LED.
(1) The operating current is much higher in order to produce optical gain.
(2) Two of the ends of the LD are cleaved parallel to each other. These ends act as perfectly aligned mirrors which reflect the light back and forth through the "gain medium" in order to get as much amplification as possible.
The typical response time of a laser diode is 0.5 ns. The linewidth is around 2 nm with a typical laser power of 10s of milliwatts. The wavelength of a laser diode can be 850 nm, 1300 nm, or 1500 nm.
Figure 2: Laser Diode.
Without debate, FO has thrown a whole new light on the future of communications. The costs of FO transmission facilities are decreasing as fast as new ways of using FO cables are growing. These new superhighways of FO cable now ring most major posts, camps, and stations and provide terabits worth of bandwidth between most military installations. By the year 2000, FO will have become the predominant transmission medium. The advent of these fiber highways comes with concomitant technologies to effectively utilize this seemingly limitless bandwidth. ATM, SONET, SMDS, FDDI, DQDB, Ethernet, and token ring are all forms of information communications (i.e., data, image, audio, and video). They all have a common requirement: a very high bandwidth to accommodate the very high speed required for these different network systems. The market demands of technologies such as DQDB, FDDI, and ATM, as well as services such as SMDS and B-ISDN, are driving the need for ultrahigh speed transport. SONET, is the harbinger of this new technical wave. An Example of this can be seen in Figure 3 which depicts the Fort Bragg Metropolitan Area Network (MAN) with an ATM/FO backbone connecting all of the major areas on Fort Bragg with optical carrier (OC)-48 fiber cable between dial central offices (DCO) with OC-12 fiber cables wide area network (WAN) connected to high-speed routers.
Figure 3: Fort Bragg Metropolitan Area Network DCO and Transmission
Loop.
Optical fibers are essential to many emerging optical technologies, including communication systems, data processing, video transmission, and computing. The bandwidth and data rates achievable using guided photons are several orders of magnitude greater than comparable systems using electronic or microwave technologies. Fibers are inexpensive low-loss waveguides, and exhibit the type of nonlinearities which can be exploited in making ultrafast all-optical switching devices, pulsed fiber lasers, multiplexers and demultiplexers, as well as various timing control modules for fiber optic communication systems. Choosing the transmission medium for a network project involves more than selecting the most cost-effective solution. To ensure the long-term reliability and performance of the system, it is important to choose a medium that can support the network requirements into the future. While it is possible to upgrade the existing copper system to support new high-speed protocols, very little of the currently installed base, mostly Category 3 cable, can support high data rate transmissions.
The FO system requirements for the proposed FO system must be based on both existing and future system requirements. Projected requirements should accommodate new and emerging information system technologies. Currently SONET is the telecommunications transmission standard for use over FO cable and the following standards are mandated by both the JTA and the JTA-Army:
The goal architecture is to utilize FO cable as the primary transmission mechanism to provide the interface between local area network (LAN), WAN, terrestrial radio, or satellite communications (SATCOM) that supports high speed synchronous transport signal (STS) frame. FO will generally be the terrestrial medium of choice in Continental United States (CONUS) because of its wide availability, cost effectiveness, and performance characteristics. Between base-level switches and within buildings, FO cable will support SONET frames at rates ranging from 51.84 megabits per second (Mbps) (OC-1) to 2.488 gigabits per second (Gbps) (OC-48).
Table 1 provides the SONET level, bit rate in Mbps to digital signal (DS) 0, 1, and 3 channel capacity for OC-1 through OC-255. OC-255 is the theoretical maximum speed, with the most popular transport interfaces today being OC-3, OC-12, and OC-48. Table 2 provides the SONET equivalent to SDH.
Table 1: SONET OC-N Speed Hierarchy.
SONET OC-N Speed Hierarchy |
||||
| OC Level (STS) | BIT RATE (Mbps) | DS0s | DS1s | DS3s |
| 1 | 51.84 | 672 | 28 | 1 |
| 3 | 155.52 | 2,016 | 84 | 3 |
| 6 | 311.04 | 4,032 | 168 | 6 |
| 9 | 466.56 | 6,048 | 252 | 9 |
| 12 | 622.008 | 8,064 | 336 | 12 |
| 18 | 933.12 | 12,096 | 504 | 18 |
| 24 | 1,244.16 | 16,128 | 672 | 24 |
| 36 | 1,866.24 | 24,192 | 1008 | 36 |
| 48 | 2,488.32 | 32,256 | 1344 | 48 |
| 96 | 4,976.00 | 64,512 | 2688 | 96 |
| 255 | 13,219.20 | 171,360 | 7140 | 255 |
| Note. Table 2 provides the SONET equivalent to the SDH. | ||||
Table 2: SONET Equivalent To Synchronous Digital Hierarchy.
| SONET Equivalent To Synchronous Digital Hierarchy | ||||
| SONET | T-CARRIER | USA | EUROPE | JAPAN |
| VT1 | DS1 | 1.544 | 2.048 | 1.544 |
| VT6 | DS2 | 6.312 | 8.448 | 6.312 |
| OC-1 | DS3 | 44.736 | 34.368 | 32.064 |
| 0C-3 | ------------------------ | ------------------------- | 139.264 | 97.728 |
Telecommunication fiber networks can be more complicated than the traditional graph-theoretic networks of nodes and links. This is due to practical and economic considerations. With the advent of fiber and its increasing deployment in networks, the risk of losing large volumes of data due to a span (physical link) cut or node failure has increased dramatically and can result in significant system outages. In the worst case, it can even result in lives lost since many military and commercial airplanes have been equipped with fiber optic networks. Thus reducing network protection costs while maintaining an acceptable level of survivability has become an important challenge for network planners and engineers. This challenge has caused a lot of new technologies to be developed in an attempt to reach the "best" solution. These emerging technologies include SONET, ATM, and passive optical technologies such as optical switching and Wavelength Division Multiplexing (WDM).
There are three SONET network protection schemes: protection switching, rerouting and self-healing. Protection switching is the establishment of a pre-assigned replacement connection by means of equipment without the network management control function. Rerouting is the establishment of a replacement connection by the network management control connection. Self-healing is the establishment of a replacement connection by the network without the network management control function. SONET self-healing rings offer several benefits in addition to service assurance such as economy, bandwidth flexibility, split and tapered feeder routes, and survivability against single-node failures. Other benefits of a SONET self-healing ring architecture are:
The migration to FO cable with its virtually unlimited bandwidth, unsurpassed reliability, and ability to support all current and future protocols is the natural choice for network engineers. Figure 4 depicts a LAN/MAN/WAN configuration with the various optical levels, add/drop SONET multiplexers, M13 multiplexers, and ATM nodes. Some misconceptions about FO cables prevented engineers from taking advantage of the medium. For example:
Until recently, copper was a clear winner in a straight cost comparison. However, recent developments have closed the gap and brought fiber and copper closer to cost parity, especially for high-performance LANs. Advances in fiber technology, higher fiber production, more affordable system electronics, and a growing base of technicians trained to install and test fiber cable have lowered the costs associated with fiber cable installation. Copper-based solutions cost more due to the stringent requirements established in ANSI/EIA-568A for Category 5 cable. It costs more to test Category 5 unshielded twisted pair (UTP) cable today than to test FO cable.
Upgrading to support 100 Mbps often requires pulling Category 5 cable and installing Category 5 outlets and patch panels, incurring expensive cable plant replacement and redesign. Copper upgrades demand more stringent installation, routing, and testing. Installing fiber cable, effectively "future proofs" the system. FO high bandwidth supports all current and proposed protocols without laying new cable. A single fiber cable specification encompasses the full spectrum of fiber-based LAN options, including Ethernet (10Base-F), Token Ring, FDDI, ATM, Fiber Channel, and Enterprise System Connections (ESCON). All specify multimode fiber with the same physical and optical parameters.
Figure 4. Typical FO System Configuration.
Many vendors providing SONET access hardware have followed the TR-08 SONET access standard. Typical SONET access interfaces include:
Detailed information on user access can be obtained in the user access section of the Technical Control Systems/Bandwidth Management Design Guide.
Typical services to ride over SONET networks include:
Detailed information on Protocols supported on SONET can be obtained in the Technical Control Systems/Bandwidth Management Design Guide.
Interest in the use of light as a carrier for information grew in the 1960s with the advent of the laser as a source of coherent light. Initially the transmission distances where very short, but as manufacturing techniques for very pure glass arrived in 1970, it became feasible to use fiber optics as a practical transmission medium. At the same time developments in semi-conductor light sources and detectors meant that by 1980 worldwide installation of fiber optic communication systems had been achieved. Some of the application areas supported by FO are:
The Institute of Electrical and Electronic Engineers (IEEE) 802.6 standard defines SONET as a transport interface and method of transmission only (i.e., it is not a network in itself). SONET uses a transfer mode which defines switching and multiplexing aspects of a digital transmission protocol. The two types of transfer modes comprise synchronous and asynchronous switching technologies. Synchronous transfer mode (STM) defines circuit switching technology, while ATM defines cell switching technology. SONET uses both STM and ATM through a fixed data transfer frame format including user data, management, maintenance, and overhead. SONET is also referred to as the SDH, which is the Bellcore term for SDH standardized by the International Telegraph and Telephone Consultative Committee (CCITT) in Europe and Asia.
STM is a time-division multiplexed system used to transmit both voice and data packets over long distances. The packets are transmitted synchronously in 125 microsecond time slots. The total STM network bandwidth is divided up into a hierarchy of fixed size channels. Each STM channel is identified by the position of its time slots within the 125 microsecond frame. An advantage of STM is that it uses circuit switches to create the connection between two points and tears down the connection after the transmission is complete. However this presents a problem. When a connection is made the end points reserve that channel, and thus the bandwidth, for themselves even if they are not transmitting. In applications that are very bursty this method is extremely wasteful. The time during bursts could be more efficiently used in other transmissions.
ATM is based on asynchronous time division multiplexing. The basic theory behind ATM is to label the data packets according to the connection and not according to a specific time. The beauty of ATM is its relative simplicity. ATM uses small packets for high speed and low delay transmission. The connection is not monopolized by a single user since the data packets are so small and easily inter-weaved. This gives it the ability to switch cells at a much higher rate. The routing of cells is determined at call set up time by setting up a virtual channel between the two end points. ATM is also very flexible because it shares both bandwidth and time. It does not break the bandwidth into specific channels but instead provides the bandwidth to the user on demand. Finally, it supports both public and LAN switching.
The advantages of deploying a SONET-based network far outweigh the disadvantages. Some of the many advantages provided by SONET include:
Some of the drawbacks of SONET deployment include:
The cost comparison summaries of various types of cable in Tables 3 and 4 demonstrate that the approximate cost to install a fiber optic Ethernet to a desktop is no more expensive than it would be to install twisted pair or coaxial Ethernet to a desktop.
Table 3: Cable Price Comparison Summary Table.
Cable Price Comparison Summary |
|||
| Duplex (two fiber) Fiber Optic Cable | Unshielded Twisted-Pair (UTP) Category 3 | Shielded Twisted Pair (STP) Category 5 | Unshielded Twisted-Pair (UTP) Category 5 |
| $0.86m/$0.26ft | $0.46m/$0.14ft | $2.05m/$0.62ft | $2.31m/$0.70ft |
| m = per meter, ft = per foot Note. The above costing information was taken from the Fiber Optic LAN Handbook by Codenoll Technologies Corporation, Yonkers, New York. A copy can be obtained by calling (914) 965-6300. |
|||
Table 4: Comparison of Twisted Pair and FO Ethernet Costs.
ETHERNET RETAIL PRICE COMPARISON |
|||
| Item | Level 3 Unshielded Twisted Pair | Level 5 UTP or Shielded Twisted Pair |
CodeNex Fiber Optic Cable |
| Network Board | $249 |
$ 249 |
$495 |
| Cable to Hub (50m) | $ 50 |
$ 338 |
$100 |
| Connectors and Patch Cables | $ 3 |
$ 53 |
$ 56 |
| Labor ($45/hr) | $ 30 |
$ 40 |
$ 45 |
| Hub (per port) | $365 |
$ 365 |
$115 |
| Total Cost | $697 |
$1,045 |
$811 |
| Note. The cost data identified in Table 3 was used to determine the cost of cables used in Table 4. | |||
The following design standards, and directives related to FO systems should be reviewed for applicability during the design of FO systems.
ATM supports a number of physical layer interfaces, speed, and line encoding including the following: SONET/SDH (various rates), DS3 (45 Mbps), and 4B/5B (100 Mbps). See physical layer interface for some of the common physical layer interfaces defined by the ATM Forum. The ATM Forum is an organization of network users, equipment vendors, and service providers that define ATM networking standards to allow for system interoperability.
The SONET NNI specifies the link between existing in-place digital transmission facilities and the SONET network node, as well as the process for converting the electrical signal into optical pulses for network transmission. This is the primary interface from the electronic world into the optical world. Three major SONET interface options are available:
While SONET provides the many advantages listed above, there remain many performance issues that either have been solved and require refinement or still need to be addressed. These issues include:
In addition, SONET requires a minimum of a Stratum 1 clock source to minimize slips and maintain transmission integrity.
SONET provides the means for end-to-end, in-service traffic performance monitoring through three types of overhead (i.e., section, line, and path). With the SONET standard, many performance parameters have been defined which can be reported by SONET compliant equipment. These include:
SONET hardware vendors can be separated into three groups. The first includes vendors pushing the SONET digital cross-connect (X) system (SDXC). The second includes those offering drop and insert multiplexer products. The third group comprises vendors that push integrated SONET message switches, such as Northern Telecom's FiberWorld SONET product line. Table 5 identifies some of the major vendors and the equipment they offer. This table is not a complete list, for a complete list of FO manufacturers and resellers see the Broadband Guide.
Table 5. SONET Equipment By Vendor Listing.
| SONET EQUIPMENT BY VENDOR | ||
| VENDOR | PRODUCT | TYPE |
| Codenoll Technology Corp | Fiber Optic Cable | All |
| AT&T Network | ServiceNet 2000 Product Line | DXC |
| Systems | (DDM-2000) | SONET Mux |
| Alcatel | RDX-33, RDX-31 | DXC |
| NEC America Inc. | IDC-B, IDC-W | DXC |
| Tellabs | TITAN 5500 | DXC |
| Rockwell | ------------------ | DXC |
| DSC Communications | ESC1, ECS3, iMTN | DXC |
| Alcatel | ------------------ | D/I Mux |
| Fujitsu | FLM-150, FLM-600, FLM-2400 | D/I Mux |
| Telco | ------------------ | Access Mux |
| Ascom Timeplex | Synchrony STS300 | Access Mux |
| Northern Telecom | FiberWorld | Switch |
| NEC America | Litespan 2000 | All |
For a complete list of FO cable types with detailed descriptions see fiber types. Figure 5 identifies the typical FO cable construction. The different types of available fiber optic cable are described below:
Figure 5. Typical Fiber Optic Cable Construction.
The following cable sizes represent samples of the cable sizes available from various manufacturers:
SONET hardware distinctions are possibly the most difficult aspect of SONET to understand; because many devices produce the same functionality, vendors are split on the choice of hardware markets and the future of SONET equipment types. Some hardware extends the distance of the CPE into SONET networks and allows both the user and provider to monitor and control the network in the same manner, rather than through proprietary T1 and T3 systems. Many types of switched, digital cross-connect (DXC) systems, and regenerators constitute the core SONET network. Examples of SONET hardware that must be considered when designing FO systems include terminating multiplexers, concentrators, add/drop multiplexers, digital loop carrier systems, SDXC, broadband switches, and regenerators.
The scope of each engineering design effort will be determined by the unique requirements of the FO systems being engineered. Numerous web sites such as Bell College of Technology provide general FO system design considerations that can be access by the design engineer. Figure 6 depicts a DDM-2000 SONET multiplexers FO network with OC-3 FO networks, both single and dual homed off of an OC-12 backbone.
The following engineering development tools are available to assist the engineer in designing a new or upgrading an existing FO system:
The formats for the development of an EIP, SDP, Information System Design Plan (ISDP), and Project Concurrence Memorandum (PCM) are available in Appendix A of the Long Haul Design Guide.
Detailed information on security requirements for long haul FO systems is provided in the Bulk Encryption Systems section of the Technical Control System/Bandwidth Design Guide.
Figure 6. Single and Dual Homed SONET Backbone.
Radios that operate in the frequency band between 3 to 30 megahertz (MHz) are designated HF radios. Most of the newer HF radios operate in a larger range of 1.6 to 30 MHz, or higher. Most long-haul communications in this band, however, generally take place between 4 and 18 MHz. Depending on ionospheric condition and the time of day, the upper frequency range of about 18 to 30 MHz may also be available. Of all of the frequency bands, the HF band is by far the most sensitive to ionospheric effects. The two basic modes of radio wave propagation at HF are ground wave and skywave. Ground wave, as the name implies, travels along the surface of the earth, thus enabling short-range communications which are directly affected by the surface of the Earth. Skywave describes the method of propagation by which signals originating from one terminal arrive at a second terminal by refraction from the ionosphere. The refracting (bending) qualities of the ionosphere enable global-range communications by "bouncing" the signals back to Earth and keeping them from being "beamed" into outer space. Skywave HF communications is widely regarded as the most challenging radio communication medium.
The recent resurgence of interest in HF radio is causing significant changes in HF radio operations, primarily due to the automation of former labor and knowledge-intensive operations. The adaptive technology known as ALE has revolutionized the field of HF radio communications by utilizing automated digital signal transmission techniques.
The HF system requirements for the proposed HF radio system must be based on both existing and future system requirements. Projected requirements should accommodate new and emerging information system technologies.
DoDD 4630.5, DoDI 4630.8, and CJCSI 6212.01 outline the basic interoperability and standards conformance requirements. The Joint Interoperability Test Command (JITC) has been designated as the executive agency for certification of such requirements and makes its test facilities available for use by DoD and industry in certification testing. The requirement for HF radio, HF ALE, and HF data modem interoperability and standard compliance testing has been established in both the military and civil sectors of the federal Government. Based on the DoDD, DoDI, CJCSI, and MIL-STD, the JITC developed two JITC Instructions (JITCI), 380-195-01A and 380-195-01B, to test compliance to the MIL-STDs.
For both ALE and radio subsystem requirements operating in the HF bands, the JTA & JTA-A mandated the following standard:
For antijamming capabilities for HF radio equipment, the JTA & JTA-A mandated the following standard:
For HF data modem interfaces, the JTA & JTA-A mandated the following standard:
An ALE radio is very similar to a typical single sideband (SSB) HF radio. The ALE modem automatically selects the "best available" channel based on link quality data stored in ALE memory. The ALE radio automatically establishes and confirms the link upon operator command. ALE radios can perform a variety of special functions including data transfer, error checking, networking, and message relay. HF radios with ALE controllers are not dependent on experienced operators to quickly determine the optimal frequencies for specific links. ALE controlled radios automatically scan preselected frequencies to determine the communications suitability of each, then store the information in a link quality analysis (LQA) table.
An ALE controller selects the best possible channel for existing conditions and automatically establishes a link ("handshake") with the distant station with only a push of a button or a software command. ALE has greatly enhanced the speed and quality of HF communications, particularly with less experienced operators. ALE radio controllers are capable of storing, retrieving, and employing at least 20 different sets of information concerning self-addressing, and 100 different sets of information concerning the addresses of frequencies of other states and nets. ALE equipped stations have the flexibility to link or network with single or multiple stations. The ALE radios can link successfully and pass data over channels with signal-to-noise levels of 10 decibels (db) below detectable voice levels. These capabilities have provided for much more efficient use of the crowded frequency spectrum. Figure 7 depicts a typical HF system configuration with external interfaces.
The ALE radio systems of the future will be able to sense their communication environment and automatically adapt to enhance their communication links as well as mitigate against detectors. The standardized radio functions reduce the cost of equipment and make interoperability among different brands of equipment more predictable, which will save an estimated 25% of the procurement cost per radio. The common use of standard radio systems utilizing ALE greatly enhance the telecommunications infrastructure for both routine and emergency traffic. Because ALE calling commands are automated and minimum direct operator involvement is required, the potential for conflict among different organizations and networks is minimized.
The HF user community continues to employ HF radio systems because of their portability, their inherent ability to be reliable communication links, and their capability to be survivable under many types of stress. As a result, the procurement of HF radios continues to increase and the expansion of HF radio systems is expected to continue. A critical part of the design process is analyzing and predicting the path losses due to climate-terrain factors. To perform HF path calculations see HF Propagation Calculator.
Figure 7. Typical HF System Configuration.
The manually-operated high frequency radio of the past required operators with extensive training, knowledge, and experience. The resurgence of interest in HF radio has led to increased automation of operator functions, thus allowing operation by personnel with minimum training.
From the user's perspective, a communication system should seamlessly integrate any available media to provide end-to-end service. In addition to this general requirement for static multimedia interoperability, many systems (especially military) require robust networks that can sustain communications in the widespread loss of assets, and that can be rapidly extended into new locales using any available facilities. It is this dynamic element that distinguishes so called "any-media" networks from the more common multimedia networks. Due to the vagaries of ionospheric propagation, HF radio node controllers (HFNC) are designed specifically to cope with dynamic connectivity. HFNCs may contain not only HF links, but also wireline, FO, mw, tropo- or meteor scatter, and satellite links. A network of HFNCs may serve as a subnetwork in a large internet, providing an inexpensive means of extending the network to remote or mobile users. Figure 8 depicts an HF subnetwork connected to the Internet.
Some of the advantages of HF radio systems are that they:
Some of the disadvantages of HF radios systems are:
Summary of HF radio ALE Functions:
Due to the relatively low bandwidth available from HF data channels, most scenarios for routing internetwork traffic through HF subnetworks involve special circumstances, such as:
One inexpensive technique for connecting an HF subnetwork to the Internet is shown in Figure 8, where, a desktop computer (labeled Gateway) executes commercial off-the-shelf (COTS) Internet Protocol (IP) software that routes packages among any data link.
The following regulatory guidelines, mandates, directives, field manuals, and industry references that are applicable to your project should be reviewed during the design and engineering of new HF radio systems:
a. Federal Standards (FED-STD):
b. Military Standard (MIL-STD):
c. Field Manuals (FM): FM 11-65, High Frequency Radio Communications, October, 1978.
Figure 8: Example HF Subnetwork to Internet Connection.
Table 6 identifies some of the major vendors and the equipment they offer. This is not a complete list. One possible source for a more complete list of HF manufacturers and resellers may be found on the American Radio Relay League (ARRL) WWW site where they list several HF Vendors.
Table 6. HF/VHF/UHF Trunked Radio Equipment Vendor Listing.
RADIO EQUIPMENT BY VENDOR |
||
VENDOR |
PRODUCT |
TYPE |
| Alinco | Handhelds, Mobiles, Base Repeaters | HF, VHF-FM; VHF/UHF FM, VHF Data (Packet), FM |
| ICOM America, Inc. | Handhelds, Mobiles, Base Repeates | Conventional (Amateur, Avionic, Land Mobile, Marine) HF/VHF/VHF |
| Kenwood Communications Corp. | LMR Mobiles, Dual-Band Handhelds, Mobiles, Packet, Base Repeaters, and Wireless | Conventional (Low Band/VHF/UHF), HF LTR Trunking/Conventional (UHF/800/900 MHz) |
| Motorola Corp | LMR Mobiles, Handhelds, Base Repeaters, and Wireless | HF/VHF/VHF, Trunking |
| Standard | Handhelds, Mobiles | VHF/UHF |
| Yaesu | Handhelds, Mobiles, | VHF/UHF, HF |
Mutipath considerations such as the causes of signal fading, selective fading, and Rayleigh distributed signal fading and their effects on data rate (i.e., bit length, multitones, parameters affecting multipath, radio frequency, path length, path location, and the local time) are all factors that must be considered when designing HF radio systems.
The JITC is the executive agency for certification of HF Radio, HF ALE, HF Data Modem, and Electronic Counter-Counter Measures (ECCM) interoperability and standard compliance testing and as such maintains an HF testbed and can provide technical data on MIL-STD-188-141A, MIL-STD-188-110A, and MIL-STD-188-148A (C) compliance HF radio systems.
Table 7 identifies examples of automated modeling tools that are available for HF systems.
Table 7: HF Automated Modeling Tools.
HF Computer Models |
||
| MODEL NAME | CODE NAME | DEVELOPER |
| High Frequency Communications Assessment Model | HFCAM | ECAC |
| HF Electromagnetic Compatibility | HF EMC2 | NOSC |
| Ionospheric Communication Analysis and Prediction Program | IONCAP | ITS |
| Minicomputer Model for Predicting the MUF in HF Communications | MINIMUF-3,5 | NOSC |
| Effect of Nuclear Burst on HF Communications | NUCOM-II | SRI |
| Propagation Forecasting and Assessment System | PROPHET | NOSC |
| Quiet-Time Lowest Usable Frequency | QLOF | NOSC |
| HFMUFES-4 Ionospheric Propagation Model | RADARC | NRL |
| Sudden Ionospheric Disturbance Grid | SIDGRID | NOSC |
| HF Skywave Propagation Model | SKYWAVE | ITS |
| X-Ray Flare and Shortwave Fade Duration Model | XRAY FLARE | NOSC |
The formats for the development of an EIP, SDP, Information System Design Plan (ISDP), and Project Concurrence Memorandum (PCM) are available in Appendix A of the Long Haul Design Guide.
Detailed information on security requirements for HF systems is provided in the Bulk Encryption Systems section of the Technical Control System/Bandwidth Design Guide.
A line-of-sight microwave link uses highly directional transmitter and receiver antennas to communicate via a narrowly focused radio beam. The transmission path of a line-of-sight microwave link can be established between two land-based antennas, between a land-based antenna and a satellite-based antenna, or between two satellite antennas. Broadband line-of-sight links operate at frequencies between 1 and 25 gigahertz (the centimetre wavelength band) and can have transmission bandwidths approaching 600 MHz. In the United States, line-of-sight microwave links are used for military communications, studio feeds for broadcast and cable television, and common carrier trunks for inter-urban telephone traffic. A typical long-distance, high-capacity digital microwave radio relay system links two points 2,500 km apart by using a combination of nine terrestrial and satellite repeaters. Each repeater operates at 4 gigahertz, transmitting seven 80-megahertz-bandwidth channels at 200 Mbps per channel.
The Army information system managers are demanding higher levels of circuit performance (less outage, better quality), robustness, security, and survivability in their increasingly complex networks transporting critical telephone, trunking, decentralized LAN, data, monitoring and control, imaging, and teleconferencing traffic. New high speed and performance digital mw equipment with enhanced link designs are keeping pace by offering a wide variety of radio architectures with more routing flexibility, protection schemes, and diversity arrangements. Table 8 provides the characteristics of unguided communications frequency bands.
Table 8. Communications Frequency Bands.
COMMUNICATIONS FREQUENCY BANDS |
||||
Frequency Band |
Name |
Digital Data |
Principal Applications |
|
Modulation |
Data Rate |
|||
30-300 Khz |
Low Frequency (LF) |
ASK, FSK, MSK |
0.1-100 bbs |
Navigation |
300-3000 Khz |
Medium Frequency (MF) |
ASK, FSK, MSK |
10-1000 bps |
Commercial AM Radio |
3-30 MHz |
High Frequency (HF) |
ASK, FSK, MSK |
10-3000 bps |
Shortwave Radio CB Radio |
30-300 MHz |
Very High Frequency (VHF) |
FSK, PSK |
To 100 kbps |
VHF Television FM Radio |
300-3000 MHz |
Ultra High Frequency (UHF) |
PSK |
To 10 Mbps |
UHF Television Terrestrial mw |
3-30 GHz |
Super High Frequency (SHF) | PSK |
To 100 Mbps |
Terrestrial mw Satellite mw |
30-300 GHz |
Extremely High Frequency (EHF) |
PSK |
To 750 Mbps |
Experimental Short Point-to-Point |
| Note. ASK = amplitude shift keying; FSK = frequency shift keying; MSK = minimum shift keying; bps = Bit per second; MF = medium frequency; LF = low frequency; EHF = extremely high frequency; SHF = super high frequency |
||||
4.3.1 Minimum Essential Requirements
The mw system bandwidth and circuit capacity requirements for the proposed digital mw radio system should be based on both existing and future bandwidth and circuit requirements. Projected data rates should accommodate new and emerging information system technologies.
The following standard is mandated by the JTA and JTA-A for radio subsystem requirements operating in the super high frequency (SHF) bands:
Table 9 provides the current North America DS1 digital hierarchy levels, designations, bit rates, and line coding required for mw systems up to DS3.
Table 9. DS1 Digital Hierarchy Summary.
DS1 DIGITAL HIERARCHY (North America) |
||||
| Hierarchy Level | Designation | # DS1 Signals | Bit-Rate (Kb/s) | Line Code |
| Zero | DS0 | 24/DS1 | 64 | AMI |
| First | DS2 | 1 | 1544 | AMI/B8ZS |
| Second | DS2 | 4 | 6312 | 6BZS |
| Third | DS3 | 28 | 44736 | B3ZS |
| Notes: 1. Alternate mark inversion (AMI), B8ZS, B6ZS, and B3ZS codes are Bipolar. 2. Reference: CCITT G.703, G.704; Bellcore TR-TYS-000499. |
||||
During the last thirty years, an ever increasing amount of telecommunication options have been provided by mw systems. Recently, numerous improvements have been introduced that have increased route capacity, reliability, and performance of digital mw systems. Consequently, such systems are being used more often to provide communications to remote locations. The use of digital modulated radio systems is now widely recognized as a flexible, reliable, economical means of providing point-to-point communication facilities. When used with the appropriate baseband systems, these mw radio systems can transmit high speed digital streams of rates up to T4. Comparative cost studies show test mw systems to be most economical when there are no existing cable or wire lines to be expanded and service to remote locations is required.
The migration to high speed digital mw to provide backup for fiber optic backbone systems, extend SONET capabilities to remote locations, increase bandwidth capability, or to replace antiquated hard-to-maintain existing mw systems are all valid reasons to consider digital mw. The specific design of the system will depend upon the location, customer, and operational requirements relating to the system to be installed. A critical part of the mw system design process is performing path profile and link analysis to determine receiver signal levels. To perform mw path calculations see RF mw Engineering Calculations.
4.3.3.1 Korean Digital Microwave Upgrade (DMU)
In Korea, the migration of the FASTBACK system that currently consists of an AN/FRC-162 radio and AN/FCC-97 multiplexer to high speed (155 Mbps) SONET digital microwave radio that utilize the digital data multiplexer (DDM)-2000 OC3 multiplexer, is an example of migrating from low-speed mw to a high-speed SONET mw system.
The system diagram depicted in Figure 9 of the Digital Microwave Upgrade DMU Phase I is a good example of what occurs when the link bandwidth is increased (8 DS1s to 84 DS1s (three 45 Mbps DS3)) with high speed SONET digital microwave and interface requirements to existing older, low speed mw technology. The Yongsan to Madison, Osan to Madison, and Camp Humphreys to Madison FASTBACK links will be replaced during Phase I with the Harris MegaStar 2000 SONET radio. The remaining FASTBACK mw links between Madison and Kamaksan, Kangwhado, and Songnam, and Kamaksan and Yawolsan, will be replaced during DMU Phase III. Figure 9 depicts the DMU system after Phase I installation. Figure 10 depicts the proposed Korean mw system after Phase III installation is completed. In conjunction with the DMU, the digital patch and access systems (DPAS) at Yongsan, Osan, and Camp Humphreys were upgraded to support up to three DS3s each.
The installed DMU system will provide a per link capacity of 135 to 155 Mbps with the capability of transporting up to 84 individual DS1s, (i.e., 3 DS3s). The upgraded system will provide the capability of bulk encrypting, adding, dropping, or redirecting any number of circuits at each repeating (intermediate) station. In conjunction with software control add/drop capability, system operators will be able to direct traffic to any network location through local or remote control. These state-of-the-art automated provisioning, alignment, and performance monitoring features will eliminate or reduce test equipment requirements, network installation, and operation costs for the network.
Figure 9. Korean Digital Microwave Upgrade Phase I System
Diagram.
Figure 10. Proposed Korea Digital Microwave Upgrade Phase III System Diagram.
The proposed upgrade of the existing mw system will include a network system management (NSM) capability (for additional infromation on NSM refer to the ISEC NSM Design Guide) that will allow more effective monitoring and control over the entire network from a centralized location, thus reducing system outages and focusing maintenance efforts. The NSM will ensure fast turnaround of management information, reduce the time and effort spent deciphering network information, and provide accurate information needed to make effective communications resource management decisions. Through the use of graphical interfaces, NSM will help operations and maintenance (O&M) personnel detect and resolve network problems quicker. Through the use of point-and-click mouse technology, the NSM operator will be able to access very detailed system information on link parameters, components (e.g., receivers, transmitters, and multiplexers), and port assignments and availability throughout the network. The system will allow management personnel to graphically illustrate network trends and statistics, generate and track trouble tickets electronically, and store problem history records on each link within the system.
An example of the timing and synchronization (T&S) issues that must be considered during the design of a high speed digital mw system is the STD-TC-0183, AN/GSO-215 Timing and Sync (T&S) Subsystem Utilizing a TrueTime Timing Global Positioning System (GPS) Receiver (TTGR), dated 1 August 1996 standard. The T&S Standard, which utilizes the Versitron clock distribution system (CDS)-10 does not provide the proper interface for the SONET DDM-2000 multiplexer. The DDM-2000 multiplexer requires a bipolar, 50% return-to-zero (RZ) alternate mark inversion (BAMI) DS-1 (with or without B8ZS coding and either super framing (SF) or extended super framing (ESF)) timing signal. The CDS-10 output is a non-return to zero (NRZ), unframed square wave (some CDS-10 driver cards have a sine wave output, but there is no bipolar framed output). The two engineering alternative solutions that were evaluated, and would satisfy the T&S requirements for the DDM-2000 multiplexer, were the Larus STS 5300 shelf and the TrueTime 56000. The Larus STS 5300 shelf is being used in Panama and the TrueTime 56000 shelf is being used in the Pentagon to support the ongoing information system upgrade there. The TrueTime 56000 system was selected as the primary T&S system to support the DMU effort.
The FASTBACK mw system that is currently being replaced in Korea is reflective of the typical legacy mw systems used by the U.S. Army to support worldwide long haul communication requirements. The existing FASTBACK system (seven individual links) provides a secure reliable means of transmitting bulk data collected along the Demilitarized Zone to command groups located in the southern part of the country. The existing equipment (i.e., radios and multiplexers) supporting the FASTBACK system has been in operation for over fifteen years, utilizing technology that is over twenty years old. The AN/FRC-162 radio is a analog radio that was modified to process digital signals. The AN/FRC-162 radio has a data rate of 12.6 Mbps, transmit power of one watt, and radio RF bandwidth of twenty-five MHz.
The AN/FRC-162 radios and AN/FCC-97 multiplexers as configured in the FASTBACK system can only support a maximum of 8 T1 circuits on a single mw link. Currently the FASTBACK system has the capability of supporting a maximum of 48 T1 circuits. The relatively limited bandwidth by today’s standard, high maintenance cost, and non-availability of replacement parts all justify upgrading the FASTBACK and other legacy mw systems.
The design parameters that the system engineer must be aware of in order to properly design a mw system include determining system requirements, selecting the link configuration, generating a multiplex/circuit plan, determining the types of orderwire and alarm systems, power sources, and height and location of equipment racks. The more information that is known about the system, the better the system engineer is able to design a cost effective system that satisfies the customer's requirements.
Some of the advantages or attributes of point-to-point high speed LOS digital microwave radio links are:
One advance which is less obvious is digital radio's outstanding flexibility in supporting the needs and objectives of the modern information network. The wide inventory of protection schemes and diversity arrangements available in digital mw links and systems surpasses that accessible to analog system designers. These are driven by the very different characteristics of digital radios: wide emitted spectrum subject to stress and distortion, error performance during transmitter and receiver data switching, and separation of its payload into 24/30 channel T1 trunks with seamless interconnectivity to fiber optic, digital private branch exchanges (PBX), high speed data, LAN, and video teleconferencing ports.
4.3.5.1 Traffic Routing Planning
In planning digital mw systems, there are numerous methods and equipment to consider. The first consideration is the traffic routing requirement and its future growth. Future growth can be considered over a five to ten year period, or closely related to the life expectancy of the equipment. Once traffic routing has been determined, the type of digital radio equipment and capacity of the multiplex equipment can be determined to provide the most cost effective system. Types of auxiliary equipment frequently required are add/drop multiplexers, M13 multiplexers, remote monitoring and control system, patch panels, bulk encryption devices, timing and synchronization systems, antennas, digital access cross-connect systems (DACS), power systems, order wire and alarm systems.
4.3.5.2 Path Profile and Link Analysis
A path profile and link analysis for each of the individual links should be performed to determine the engineering changes that will be required to engineer a new system or transition from a low speed digital or analog mw system to a high speed digital mw system that will support an expanding mission utilizing new and emerging technologies. The factors (output power, bandwidth, data rate, antenna location, size of antenna, waveguide length, and link distance) that determine mw link reliability for the existing system cannot be applied in all cases to the new system and achieve the same level of link reliability. A change in the data rate, the bandwidth of the RF carrier, effective output power, antenna height, and distance of the path will cause changes in individual link reliability which translate directly to changes in overall system reliability.
4.3.5.3 Diversity and Protection Schemes
Protection schemes evolved with an increasing sensitivity to network outages and survivability. Traffic disconnects, loss of data throughput, and the other effects of long-term circuit outage (10-3 consecutively severely errored second (CSES), consecutive 10-3 bit error ratio (BER) severely-errored seconds, per event) are not only annoying, inconvenient, and sometimes costly, but in crucial defense networks such occurrences could place lives in danger. The limited number of protection and diversity schemes available to analog mw engineers of the mid-70s where short-term fading outages which caused no major traffic disconnects. This is not acceptable for today's high speed data network systems. The existing protection and diversity schemes (i.e., hot standby, space, and frequency diversity) have been augmented with protection schemes such as angle, hybrid, quadruple diversity, self-healing path-switched, and line-switched rings.
The specific type of diversity arrangement assigned to a mw link is subject to the user's availability and performance objectives, equipment configurations, path geometry, and atmospheric conditions. Several diversity configurations are available:
The following levels represent the relative effectiveness of equipment protection and diversity schemes to equipment and infrastructure failure and long and short term propagation fade activity that will be used to compare various protection and diversity schemes.
While the terms "protection" and "diversity" are often used interchangeably when applied to mw links, protection commonly implies a level of security from long-term (>10-3 CSES/event) traffic disconnects, while diversity arrangements greatly reduce the numbers and duration of short-term (<10-3 CSES/event) outages. Table 10 provides examples of the relative effectiveness of various protection and diversity arrangements schemes.
Table 10. Relative Effectiveness of Protection and Diversity Arrangement Schemes.
Microwave Link Protection Schemes |
||||||
| Arrangement | Equipment Failure | Antenna/ Feeder System Failure | Multipath Fade Outage | Ducting and Rain Outage | Infrastructure (Site) Failure | |
| Antenna | Radios | |||||
| TTRR | Hot Standby (HS) | 2 | ---- | ---- | ---- | ---- |
| TTR/R | Space Diversity (SD) | 2 | P | 2 | ---- | ---- |
| TR/TR | SD + Split Xmtrs (ST) | 2 | 2 | 2 | ---- | ---- |
| TTRR | Angle Diversity (AD) | 2 | P | 2 | ---- | ---- |
| TTRR (TR/TR) | Frequency Diversity (FD) | 1 | (1) | 2 (3) | ---- | ---- |
| TTRR-TR/TR | Hybrid Diversity (HD) | 1 | P | 1 | ---- | ---- |
| TRR/TRR | Quadruple Diversity (QD) | 1 | 1 | 1 | ---- | ---- |
| T-R/T-R | Path-switched Ring (PSR) | 3 | 3 | P | 3 | 3 |
| T-R-T-R | Line-Switched Ring (LSR) | 4 | 4 | P | 4 | 4 |
| T = Transmitter; R = Receiver | ||||||
The selection of the best protection schemes available to the system engineer depend upon the availability (long-term outages) criterion and equipment features. Some diversity arrangements have protection attributes, as some protection schemes provide an element of diversity improvement. For example:
The probability of long-term outage (with traffic disconnect) due to the following events is greatly reduced with the appropriate protection schemes listed above.
Optimum diversity arrangements greatly reduce, perhaps essentially eliminate, the number of short-term multipath fade outages in digital mw links. Further, the duration of any remaining data outages is also greatly reduced. Diversity configurations can also lessen the impact of fade margin degradation cause by interference, power fading, and other long-term occurrences. For example:
Electromagnetic Interference (EMI) and other environmental effects.
The following regulatory guidelines, mandates, directives, and industry references should be reviewed during the design and engineering of new mw radio systems as they apply:
4.3.5.4 Procurement Sources for Hardware and Software
Some of the major manufacturers of mw LOS radio systems and components are are provided in Table 11.
Table 11. mw Radio Equipment Vendor Listing.
mw RADIO EQUIPMENT BY VENDOR |
||
VENDOR |
PRODUCT |
TYPE |
| AT&T | mw Radio Systems | MICROPASS Series 8000, FASTWAVE Series 875 LAN |
| Alcatel Network Systems | mw Radio System | MDR-4000e Series Digital & 155 Mbps SONET OC-3s |
| Harris Farinon Division | mw Radio Systems | MegaStar 2000 155Mbps SONET-OC-3 |
Digital mw radio links and systems are characterized by internationally-standardized terms and objectives that clearly define their performance and robustness in a dynamic fading environment with external interfaces. Sound engineering practice dictates that the design of a digital mw radio system start with the assignment of clearly-defined easily verifiable availability and performance objectives compliant with user requirements. Table 12 provides one-way annual outage and path reliability objectives for various systems and a typical 40 km/25 mile (mi) digital mw link. It shows that system length has the most influence on per-hop performance objectives.
Table 12. Microwave One-Way Annual Outage and Path Reliability Objectives.
MW ONE-WAY ANNUAL OUTAGE AND PATH RELIABILITY OBJECTIVES |
|||
PARAMETER |
Bellcore Short-Hual |
CCIR High-Grade |
Long-Haul |
| System Length, km/mi | 400/250 |
2500/1,500 |
6400/4,000** |
| End-to-End Reliability, % | 99,995 |
99,986* |
99.995 |
| End-to-End Outage, sec/yr | 1,600 |
4,200 |
1,600 |
| Per-Hop Outage, sec/yr | 160 |
70* |
20 |
| Per-Hop Outage, sec/km/yr(sec/mi/yr) | 4 (6.4) |
1.8 (2.8)* |
0.5 (0.8) |
| Per-Hop Outages, sec/any month | 52 |
24 |
7* |
| Per-Hop Annual Reliability, % | 99.9995 |
99.9998 |
99.99993 |
| Notes. 1. Very short-haul (<250 mi) system per-hop outage objective: 99.999% (315 sec/yr) 2. * = Objective scaled at 10° C (50° F) average temperature. 3. ** = Objective scaled at 10° C (50° F) average temperature. 4. sec = second; yr = year; % = percent |
|||
4.3.6.1 Microwave System Engineering Development Tools
The formats for the development of an EIP, SDP, Information System Design Plan (ISDP), and Project Concurrence Memorandum (PCM) are available in Appendix A of the Long Haul Design Guide. In addition to the tools found in this appendix the EDX Signal Proâ Comprehensive Engineering Software for Wireless Communication System Design, that will perform analysis on mw, amplitude modulation (AM), frequency modulation (FM), and television broadcast coverage software.
4.3.6.2 Microwave System Security Consideration
Detailed information on security requirements for mw systems is provided in the Bulk Encryption Systems section of the Technical Control System/Bandwidth Design Guide.
Trunked land mobile radio (LMR) system employs a trunking technique which uses dynamic channel assignment to obtain efficient use of the frequency spectrum. The trunking technique essentially links a certain number of channels, typically 5 to 20 pairs, at the same site and automatically switches between them. The trunking technique achieves a greater efficiency (more users) than is possible on the same number of single channels. Trunking technology can provide radio users efficient, cost-effective, communications that meet the National Telecommunications and Information Agency (NTIA) policy direction for movement to narrow-band communications. The technology is current with industry standards and is available from several manufacturers.
Trunking permits a large number of users to share a relatively small number of communication paths or trunks. This sharing of communication paths is managed automatically by a computer. Channel selections and other decisions normally handled by the radio user are made by a computerized switch in the central controller. Thus, the user needs only to pick up the radio and talk, just as one does an ordinary telephone. Channel assignment is automatic and completely transparent to the individual user.
4.4.1 Minimum Essential Requirements
The trunked radio system requirements for the proposed trunked radio system must be based on both existing and future system requirements. Projected requirements should accommodate new and emerging information system technologies.
The trunked LMR system is a spectrum efficient method to meet non-tactical land mobile radio operational requirements. Army Spectrum Management policy and procedures for the trunked LMR system is required to provide guidance to users and planners. Army Regulation (AR) 25-1 and AR 25-3 provides Information Mission Area (IMA) and acquisition policy and procedures. This policy memorandum is consistent with and incorporates the policy and procedures of the NTIA.
The Army is encouraged to use trunked LMR systems to meet non-tactical LMR operational requirements. Army installations or organizations with new LMR requirements will coordinate with other military Services or Federal Agencies that have installed or planned trunked systems to support that respective geographical area. It is a Federal policy to coordinate between agencies to obtain the economical, technical, and operational advantages of a planned or existing system. Trunked LMR systems may be established by an individual Federal Agency or cooperatively among several Federal Agencies where agencies are concentrated in a geographical area. The lead Federal agency will obtain authority for all stations desiring to use the trunked system. If acting as a lead agency, Army units will comply with the procedures below. The procedure is essentially a two step process: 1) obtain Federal system approval and, 2) obtain frequency assignments for the trunked system. Should growth or increased use require the expansion of a previously approved trunked land mobile system, a Request for Expansion/Additional Channels form must be submitted for approval.
NTIA directed that trunked LMR systems transition from a 25 kHz channel spacing to a 12.5 kHz beginning on 1 January 1995. Planning and programming for new trunked system requirements after 1 January 1995 must include equipment that meets the 12.5 kHz standard.
There are many factors to consider when deciding whether or not trunking is right for the project. First, it may help to understand how trunking works. Trunking is the mutual sharing of a small number of communication paths by a large number of users. The process may be compared to the way modern telephone systems operate; trunking uses a central switching station to assign channels automatically to users on demand. When telephone users pick up their telephone, a line is automatically available to them. The same applies to a trunked radio system. This makes both channel efficiency and privacy possible in trunked radio.
By contrast, in conventional two-way radio multiple users share a common RF channel and compete for air-time. In addition, users not only listen to other conversations, they are often required to monitor a channel in order to make a call of their own. In a trunked system, the switching station is known as the central controller. This computerized switch automatically manages the assignment of channels for maximum efficiency. Channel assignment is, therefore, completely transparent to the individual user.
Conventional systems vary in both size and sophistication. With regard to size, trunking systems are often configured as single-site or multi-site depending on the coverage or "talk range" that is desired. The typical trunked radio system configurations are identified below.
- Voting - Multiple satellite receivers are added to a system to extend coverage of an area. Receivers can be added to remote areas or buildings that are outside the normal receive range of the system. To ensure that the best audio from these receivers is processed, a comparator selects the best signal to be passed on to the desired recipients. This process is known as receiver voting.
- Simulcast - When a wide geographical area must have communications throughout the system, simulcast provides the solution. Simulcast provides wide-area coverage by simultaneously keying multiple transmitters that share a common frequency. Because simulcast sites typically overlap, communications can be received by users no matter where they are in the system. These systems provide consistent communications throughout a large city, metropolitan area, county, or even country.
- Multicast - Similar to simulcast, multicast provides wide-area coverage using multiple overlapping sites with different sets of frequencies throughout the system.
In addition to system size, systems also vary in sophistication. The following are some differing system types.
- Digital 12 kbps SECURENET encrypted operation is available on conventional, 25 kHz analog channels.
- Digital encryption is available for digital systems in either 25 kHz or 12.5 kHz channel bandwidths.
Until the development of high-capacity underseas cable and the advent of satellite capabilities, HF radio was the primary long-distance medium. Radiotelephone and radio teletypewriter were the principal communications services provided. High power transmitters with massive antenna fields and many highly trained personnel were required to make the system work. HF radio was the primary means of long haul communications because it provided communications with land, sea, and air forces at all distances. Traditionally post HF systems such as police, fire, emergency medical services (EMS) and the Directorate of Engineering was stand-alone systems operating on different assigned frequencies within the HF band.
Trunking offers many advantages, including faster system access, better channel efficiency, user privacy, and the flexibility to expand. For example, a post system can be divided into fleets by agency, such as police, fire, EMS and the Directorate of Engineering. Each fleet can then create its own functional talkgroups or sub-fleets. The Directorate of Engineering could create a talkgroup for each of its departments, such as streets, water and sewer, and garbage collection. Because of its flexibility, a trunked system can expand along with operations to accommodate a growing number of users and restructuring of talk groups. It can be continuously upgraded with software.
In evaluating the advantages of a trunked communications application for a project, one must define customer needs, the challenges the operation faces, and the available budget. As in most situations, the customer drives the process in a team effort to determine what kind of system is most appropriate.
Because of its efficient channel usage, a trunked radio system affords reliable, immediate access to a channel during emergencies and advanced features to help ensure that these calls will get through. The dynamic regrouping feature allows the system to quickly reassign units so users can talk to each other during an emergency. Lost or stolen radios can be disabled remotely by the central controller. The unit ID feature can identify a radio that has been keyed by the user, even if user is unable to speak. The telephone interconnect feature even enables users to receive and make telephone calls directly from the radio.
There are several additional advantages of trunked radio systems:
These benefits allow for a more dynamic and economical means of organizing fleets and talkgroups. This ability to combine multiple departments or agencies under one system while maintaining independent operations is the cornerstone of the trunking advantage.
The following applicable regulatory guidelines, directives, and industry references should be reviewed during the design and engineering of new trunked radio systems as they apply:
- MIL-STD-188-141A, Medium and High Frequency Radio Equipment, Interoperability, and Performance Standards.
- MIL-STD-188-140A, Equipment Technical Design Standards for Common Long-Haul/Tactical Radio Communications in the Low Frequency Band and Lower Frequency Bands.
- AR 25-1, The Army Information Resources Management Program, 18 November 1988; Change Notice I02, dated 8 April 1993; Change Notice I03, dated 1 September 1993; and Change Notice I04 dated 15 November 1993.
- AR 25-3, Life Cycle Management of Information Systems.
- Federal Communications Commission (FCC), Part 68 Connection of Terminal Equipment to the Telephone Network, October 1982.
- FED-STD-1023 Telecommunications: Interoperability Requirements for Encrypted, Digital Voice Utilized with 25 kHz Channel FM Radios Operating above 30 MHz, 25 September 1989.
- FED-STD-1102 Telecommunications; Land Mobile Radio, Project 25 Common Air Interface, March 1994 (Draft).
- FED-STD-1108 Telecommunications; Land Mobile Radio, Project 25 Vocoder, 16 March 1994.
- FIPS-PUB-140 Telecommunications, General Security Requirements for Equipment using Data Encryption Standard, 14 April 1982.
- Policy Memorandum Number 95-01, Policy and Procedures for Trunked Land Mobile Systems, 1995.
- EIA-152-C, Minimum Standards for Land-Mobile Communication FM PM Transmitters, 25-866 MHz, December 1988.
- EIA-204-D, Minimum Standards for Land-Mobile Communication FM or PM Receivers, 25-866 MHz, January 1982.
- EIA-220-B, Minimum Standards for Land-Mobile Communication Continuous Tone Controlled Squelch Systems, March 1979.
- EIA-222-C, Structural Standards for Steel Towers and Antenna Supporting Structure, 1976.
- EIA-316, Minimum Standards for Portable/Personal Radio Transmitters, Receiver, Transmitter Combination Land Mobile Communications FM or PM Equipment, 25-1000 MHz, August 1979.
- EIA-329-B, Land Mobile Communications Antennas, Minimum Standards, Part 1-Base or Fixed Station Antennas, September 1989.
- EIA-329-B, Land Mobile Communications Antennas, Minimum Standards, Part II-Vehicular Antennas, September 1989.
The installing agency obtains frequency assignments for trunked land-mobile radio systems and is responsible for managing the system. Individual users, units, or agencies are not required to obtain frequency assignments to share the system obtained by the responsible agency. A trunked system normally requires a minimum of five frequency pairs initially, expandable to a maximum of 20 pairs or channels. In certain high use frequency congested areas, selecting a sufficient number of frequencies from the designated list is nearly impossible. Existing frequency assignments allowed to remain in effect and problems from intermodulations restrict using frequencies from the designated list. In such cases, replacement frequencies may be selected using the standard frequency selection guidelines. The POC for questions concerning frequency assignments for trunked land-mobile systems can be reached at DSN: 221-8214, Commercial: (703) 325-8214.
4.4.4.1 Procurement Source for Hardware and Software
Trunking technology can provide radio users efficient, cost-effective communications that meet NTIA policy direction for narrow-band communications. The technology is current with industry standards and is available from several companies (i.e., AT&T, Motorola, Siemens, L.M. Ericcson, Alcatel, Hughes, Nokia, and others). The U.S. Army Base Support Trunked Radio System (BSTRS) contract is an example of an available contract vehicle for the procurement of trunked radio system components.
For long-haul user interface, various radio subsystems are available to connect into the long-haul trunk. Examples are ManPack LOS as operator input devices, local trunked nets interconnected through a central hub with interconnectivity into the long-haul backbone, and connectivity through on-orbit transponders. When the engineering changes to a conventional system, there are several available options: retain the existing conventional system; upgrade the existing system with advanced conventional features; or migrate the entire system to trunking. Factors that should be considered in deciding for or against trunking radio systems are:
Other tools that are exclusive to trunking include: priority levels, out-of-range indication, busy system retries, enhanced system diagnostics, and highest priority for emergency calls during busy conditions. If all of these features are necessary, then trunking probably is the right choice.
Table 13 shows recommendations for the sizing of trunked radio systems.
Table 13. Trunked Radio System Sizing Table.
TRUNKED RADIO SYSTEM SIZING TABLE |
|
| CHANNELS | USERS |
| 0 to 5 | 300 |
| 6 to 10 | 3001 to 1,000 |
| 11 to 15 | 1,001 to 2,000 |
| 16 to 20 | 2,001 to 3000 |
4.4.5.1 Trunked Radio System Engineering Development Tools
The formats for the development of an EIP, SDP, Information System Design Plan (ISDP), and Project Concurrence Memorandum (PCM) are available in Appendix A of the Long Haul Design Guide.
4.4.5.2 Trunked Radio System Security Consideration
Detailed information on security requirements for trunked radio systems is provided in the Bulk Encryption Systems section of the Technical Control System/Bandwidth Design Guide.
4.5 Copper Cable (Coaxial and Twisted Pair) Systems
Copper cable is a relatively inexpensive, well-understood technology that is easy to install. It is the cable of choice for the majority of network installations. However, copper cable suffers from various electrical characteristics that impose transmission limits. For example, it is resistant to the flow of electrons, which limits its distance. It also radiates energy in the form of signals that can be monitored and is susceptible to external radiation that can distort transmission. However, current copper cable products support Ethernet transmission speeds up to 150 Mbps, with work continuing on technology that will boost twisted pair transmission rates above 500 Mbps. Figure 11 depicts a UTP eight conductor cable, the typical cable used for network communication. Copper cable today is less known as a long-haul transmission medium and is associated more with facility and campus cable systems.
Figure 11. Category 2 Unshielded Twisted Pair (UTP) 8
Conductor.
4.5.1 Minimum Essential Requirements
The cable system requirements for the proposed cable system must be based on both existing and future system requirements. Projected requirements should accommodate new and emerging information system technologies.
Engineers who must design cable networks face some critical decisions. Cables and cable equipment must meet current and future requirements for data transmission, electrical characteristics, and topology. Cable manufacturers have been able to boost data transfer rates on relatively inexpensive copper twisted pair wire where it should meet future demands for high-bandwidth to the desktop. To help engineers make informed decisions and design workable cable systems, two new standards have emerged from the Electronic Industries Association/Telecommunications Industries Association (EIA/TIA). The first is a cabling standard called the EIA/TIA 568 and the second is EIA/TIA 606 commercial building wiring standard. Figure 12 depicts the typical cable types used for network communication.
The migration to Category 5 cable to meet the high transmission rate and other standards in the works that deliver hundreds of Mbps can be attributed to tighter twisting of copper pairs, better materials, improved hardware designs, and new access methods. All of the cable system components must comply with the standard specifications. That includes the connectors, cables, wallplates, patch panels, and terminations to eliminate cross-talk between wire pairs. Older modular connectors and jacks are not suitable for Category 5 installation. In addition, the twists in the wire must be maintained all the way up to the connection point. Due to those specifications, many existing cable plants must be completely upgraded.
The performance characteristics of Category 5 cabling and connectors can provide 100 Mbps to 150 Mbps network throughput. Any network that operates at this rate can take advantage of the cabling scheme. The standard is designed to support current and future networking needs. Recent studies by AT&T Paradyne indicate that Category 5 UTP cable can transmit up to 950 Mbps over 100-meters distances.
With the possibility of much higher data rates in the future, it would seem that Category 5 UTP is the most logical cable to install, preferable even to FO cable when compared in price and ease of installation. However, many organizations cannot afford to pay now for what might be needed in the future, even though installing lower-grade cable will limit future growth. System engineers need to carefully evaluate current and future needs for emerging high-bandwidth multimedia, video conferencing, and imaging applications.
Figure 12. Typical Cable Types used for Network Communications.
In the last five years, networking technology has rapidly evolved to encompass up to 100-Mbps data transmission over Category 3 cables using complex coding and up to 155 Mbps Fast Ethernet (100Base-Tx) over Category 5 cabling using simple coding. Today, 100 Mbps Fast Ethernet is well positioned to overtake 10Base-T as the basic networking platform for desktop applications. Category 5 also has the potential of supporting gigabit applications such as 1000Base-T and 1.2 Gbps ATM.
Many vendors are advertising higher-performing cables and, to a lesser extent, enhanced-performance connecting hardware and patch-cord assemblies that exceed the minimum Category 5 specification. There are many exaggerated claims regarding enhanced-performance Category 5 cables. These performance improvements are being marketed aggressively by manufacturers to differentiate their products.
There are four available alternatives if cable performance beyond Telecommunications Industry Association (TIA)/Electronic Industries Association (EIA) 568A and International Standards Organization for (ISO) 11081 are required:
Table 14 summarizes the pros and cons associated with each approach.
Table 14. Beyond Category 5 Requirements.
Future Cable Considerations Beyond Category 5 |
||||||
Cable Type |
Cost vs. Basic Cat 5 UTP |
EMC Performance |
B/W of Link (MHz) ACR> 0 |
Installation Labor |
Ease of Field Test |
Other Issues |
Premium UTP |
180% |
Good if balanced |
150-300* |
Low |
Medium |
Most compatible existing equipment |
FTP/ScTP |
200% |
Very good |
100-200 |
Low |
Medium |
How to measure shield performance? |
SSTP |
340% |
Excellent* |
600-1200 |
Moderate |
Difficult |
No connector yet |
MM Fiber |
250% |
Perfect |
2000+ |
High |
Easy |
Many advantages |
| * -- Depends on quality of
installation practice. vs -- versus; ACR -- Attenuation to crosstalk ratio MM -- Multimode FTP -- fiber and twisted pair ScTP -- Screened twisted pair EMC -- electromagnetic radiated interference Cat -- Category |
||||||
In September 1997, the ISO/International Electrotechnical Commission (IEC) announced preliminary requirements for Category 6/Class E and Category 7/Class F. Category 6 will support applications with channel bandwidth of at least 200 MHz over UTP and/or STP, and will retain compatibility with the familiar RJ-45 style connector. Category 7 will support 600 MHz applications over SSTP, and will require a new connector in order to support all four pairs. It may be mid-1998 or later before these standards are fully specified.
Given that all of the present and planned Army networks will run on Category 5, there is good reason for caution before selecting a higher cost alternative. In the absence of special circumstance, such as heightened emissions, distance or security concerns, there is no reason why the standard Category 5 cable, properly installed, shouldn't meet the requirements.
Copper cables are either balanced or unbalanced; twisted pair cable is balanced, whereas coaxial cable is an unbalanced media. Cable is subject to the parameters that are related to the materials used to create the cable and the construction design. These parameters are attenuation, capacitance, delay distortion, and noise. The longer a cable is, the more likely these parameters will cause signal distortion. In addition, increasing frequency of the signal to boost the data transfer rate will require a reduction in the cable lengths to avoid distortion.
One other general characteristic of copper cable is related to the location where it is installed. In order to comply with the National Electrical Code (NEC), all cable installed in the plenum space (airspace between the ceiling and the next floor or roof) must be installed in metal conduit, or must meet local fire codes. If cable should burn, it must not produce noxious or hazardous gases that could be pumped to other parts of a structure through the plenum. Consequently, some normal cable types are insulated with polyvinyl chloride (PVC) materials. Plenum-rated cables are insulated with fluoropolymers such as DuPont's Teflon.
The three primary types of copper cable used to transmit digital signals are:
Figure 13. Twisted Pair Cable Construction.
Twisted pair cable is available in the following categories:
Cable systems utilizing copper or coaxial cable should be used only where the local circumstances require them because of installation problems in modifying existing physical facilities.
The following are applicable regulatory guidelines, standard, directives, and industry references that should be reviewed during the design and engineering of new copper cable systems:
4.5.4.1 Procurement Source for Hardware and Software
The more common cable conductor gauges used to support cable systems are:
Traditionally system engineers have relied on copper cable (inside plant and outside plant) all the way to the subscribers; however, the requirement to boost the signal in large area networks have limited the bandwidth of the system. Today fiber optic cable is the preferred backbone cable to reduce signal attenuation and need for line amplifiers. Fiber optics have allowed the system engineer to significantly boost bandwidth and more than double the number of circuits supported by copper systems.
EIA/TIA 568 provides a structured wiring for cabling systems that allows consideration for future growth and system reconfiguration. This standard provides a uniform wiring system and supports multivendor products and environments. Structured wiring forms an infrastructure with pathways for critical parts of a network. The system includes cables, communication connectors, jacks, plugs, adapters, balums, patch panel systems, and electronic components. Ideally, it provides a way to transmit data, video, voice, and other information. Structured wiring systems are standard-based. Distances, topologies, and physical specifications are already defined and future cable requirements have been accommodated; thus, a building can be wired without any prior knowledge of the data communication equipment that will use the wiring. Cable plants have become easier to manage and faults are easier to isolate.
4.5.5.1 Copper Cable System Engineering Development Tools
The formats for the development of an EIP, SDP, Information System Design Plan (ISDP), and Project Concurrence Memorandum (PCM) are available in Appendix A of the Long Haul Design Guide.
4.5.5.2 Copper Cable System Security Consideration
Detailed information on security requirements for copper cable systems is provided in the Bulk Encryption Systems section of the Technical Control System/Bandwidth Design Guide.
4.6 Personal Communications Systems
Wireless telecommunication is considered to be one of the growth industries for the 90s. Wireless and mobile services entail a full range of essential communications media and services, using technological applications for sending and receiving voice, data, and graphics. Wireless data networks give users freedom to roam while allowing them to communicate to and from a portable computer or terminal. The following list provides some of the wireless data networks, architectures, issues, challenges, methodologies, and techniques that are currently available:
4.6.1 Minimum Essential Requirements
The IS-54 standard requires that each frequency channel be divided into time slots within a data frame. Each channel slot comprises a single circuit path. The number of time slots within a frame determines the number of users who can use the channel at any given time. In the IS-54 system, time-division multiple access (TDMA) is used in conjunction with frequency-division multiple access (FDMA). FDMA is necessary to divide the frequency allocation into a number of narrow-band channels.
The IS-95 standard is based on code-division multiple access (CDMA). CDMA is not capacity limited by the number of channels or the number of time slots as are the analog FDMA and TDMA systems. CDMA systems are capacity limited by the performance degradation caused by interference among users. There are, typically, two techniques used for CDMA: frequency hopping spread spectrum and direct sequence spread spectrum. Both techniques require a unique digital code (called a psuedorandom noise (PN) code) to be assigned to each user. The PN code is used to spread the data elements over multiple frequencies for transmitting and reassembling the data elements from the frequency spread for reception.
In a frequency hopping spread spectrum, a wide frequency band is divided into many narrow-band channels. The PN code is used to make the transmitter hop from one channel to another at a rapid rate in the psuedorandom sequence. For reception, the same PN code is used to rapidly tune the receiver in the same psuedorandom sequence. There are two methods to generate the direct sequence spread spectrum. One method modulates the carrier with the data stream, then modulates the resultant signal with the PN code sequence. The second method (the one most commonly used) modulates the PN code sequence with the data stream, then modulates the carrier with the resultant signal.
GSM 900 has been adopted as the first global standard for mobile telephone due to its open standards, support for roaming and multivendor interworking. The GSM 900 standard is currently being used by over 200 operators in 105 countries around the world with 148 networks on "Air" to date.
The licensed block PCS technologies can be divided into two types of systems based on intended coverage. One, called a high-tier system, is targeted for large cell applications much like existing cellular systems. The other, a low-tier system, is targeted for microcell applications. The high-tier technologies tend to be robust against the impairment effects of radio transmission, such as multipath from reflections, scattering, and Doppler spreading created by motion of the mobile. However, high-tier technologies are commensurately more complex and provide lower quality voice and lower data rates. The low-tier technologies are less tolerant of multipath and are designed for operation at pedestrian speeds. However, low-tier technologies provide higher quality voice and higher data rates. Cell radii for the high-tier systems can range up to one-hundred miles, while cell radii for the low-tier systems range only up to a few hundred yards.
All proposed PCS technologies are digital. In digital transmission of voice, the original analog voice signal is converted to a sequence of binary numbers (bits), encoded with error detection and correction bits, modulated, possibly spread in frequency, and then transmitted. At the receiver, the signal is despread if necessary, demodulated, decoded, and then converted back into an analog signal.
PCS systems can provide data transmission services in addition to voice services. There are two primary ways to provide data transmission in a PCS system designed for voice transmission. In one case, the data stream bypasses the voice encoder and is injected directly into the digital system. This is the most appealing method since it provides the maximum data rate. The difficulty is that it requires specific modifications to the PCS system. There must be special equipment at both ends of the radio link to give access to the data stream. This requirement makes the service more expensive. The other approach is to use the more traditional voice-band modem and not bypass the voice encoder. A traditional voice-band modem modulates the audio frequency carrier with the data stream for transmission over a voice circuit. The frequency spectrum of the modem output falls within the required voice bandwidth.
The characteristics of the voice encoder are important when using the voice-band modem. PCS systems use two basic methods of voice encoding to convert the analog voice signal into a digital bit stream: waveform (or direct) encoding and predictive encoding. Waveform encoders tend to provide very high quality voice transmission, but require a higher bit rate. The higher bit rate reduces the spectral efficiency of the system for voice circuits. Predictive encoders require a lower bit rate and are, therefore, more spectrally efficient, but provide poorer quality voice. Because of the higher data rate of the encoder, waveform encoders provide a greater voice bandwidth than predictive encoders. Therefore, waveform encoders can support voice-band modems with higher data rates than predictive encoders. Data transmission, using a traditional voice-band modem, will result in a lower data rate than that achievable by bypassing the voice encoder.
PCS comprises the services and technologies that are the second generation of digital mobile telephone services. These include both voice and data services coupled with the benefits of advanced network services. While PCS was originally envisioned as an advanced mobile telephone system based on a microcell or picellular architecture, market forces are driving it in the direction of a system similar to digital cellular, but operating at higher frequencies. PCS does, however, offer paging and short messaging services among other services not found in digital cellular.
The spectrum allocated for PCS in the United States, shown in Table 15, is divided into six licensed blocks and one unlicensed block. The unlicensed block is to be used for low power voice and data systems such as wireless PBX. Blocks A and B are licensed within 51 service areas based on the major trading areas (MTA), and Blocks C, D, E, and F are licensed within 493 smaller service areas based on basic trading areas (BTA) set forth in the 1992 Rand McNally "Commercial Atlas and Marketing Guide". The PCS rules (FCC Docket 90-314) specify that Block A, B, and C "licensees must provide coverage to one third of their service area population within five years and to two thirds within ten years" and that Block D, E, and F "licensees must provide coverage to 25 percent of their service area population within five years or submit a showing of equivalent or substantial service". One intention of these "build-out" requirements is to ensure service to rural customers. Table 15 depicts the frequency allocations for PCS in the United States.
Table 15. United States PCS Frequency Allocations Table.
PCS Frequency Allocations Table |
||
Frequency Block |
Mobile-to-Base Station |
Base Station-to-Mobile |
Block A |
1850-1865 MHz |
1930-1945 MHz |
Block B |
1870-1885 MHz |
1950-1965 MHz |
Block C |
1895-1910 MHz |
1975-1990 MHz |
Block D |
1865-1870 MHz |
1945-1950 MHz |
Block E |
1885-1890 MHz |
1965-1970 MHz |
Block F |
1890-1895 MHz |
1970-1975 MHz |
Unlicensed |
1910-1930 MHz |
2390-2400 MHz |
Technical standards for the PCS air interface are being developed in the Joint Technical Committee (JTC) on Wireless Access. The JTC is a joint activity between Committee T1 and the Telecommunications Industry Association (TIA). Within the JTC, six air interface technologies are being standardized for the licensed PCS blocks. A seventh standard may be added which will be based on the Digital European Cordless Telephone (DECT) standard. Four standards are being developed for the unlicensed band, three are based on current digital cellular standards.
Another key benefit of a digital system is the standards that are being set by the Association of Public Safety Communications Officials (APCO). This user-driven and user-controlled initiative, called APCO 25, is setting the standards for digital two-way radio technology for federal, police, and fire agencies. In addition to APCO, the project is supported and endorsed by several other leading organizations. Five major cellular manufacturers have agreed to produce equipment that will conform to all Project 25 standards, thus enabling an organization to migrate to full compliance. Project 25 established four key objectives for digital two way radio standards:
At the same time, since many organizations already have a substantial investment in their current analog systems, a clear migration path to digital must be established. That means new digital radio equipment has to offer backward compatibility with a manufacturer's existing analog systems. As a result, subscriber radios that comply with Project 25 will offer migration from existing systems to new narrow band channels in conventional and trunked systems.
PCSs have evolved from the old Mobile Telephone Service (circa 1946). Advances in available technology have allowed additional services (e.g., data) to be added to the original voice communications capability. Advancing technology has also allowed significant increases in efficient use of the allocated frequency spectrum.
The original cellular service in the United States was an analog system which used FM and FDMA. This system, called Advanced Mobile Telephone Service (AMPS), is still in use. Analog systems have been widely successful in serving millions of subscribers worldwide. These systems vary in complexity and include some of the most advanced cellular networks and many smaller emerging markets. Vendors continue to develop analog systems to address specific customer requirements. However, digital systems are displacing the analog systems.
Digital cellular systems in the United States fall into two categories: TDMA and CDMA. Both categories use the IS-41 standard to access the public switched telephone network (PSTN). Cellular service in the United States has frequencies allocated in two different blocks for each defined service area. The frequency allocations for cellular service in the United States are shown in Table 16. Service areas for licensing of cellular operations were defined by the FCC based on modifications of definitions by the Office of Management and Budget. These areas consist of 306 Metropolitan Statistical Areas (MSA) and 482 Rural Service Areas (RSA). There are some rural areas within some MSAs and some RSAs which are more "rural" than others. Each of the two different frequency blocks has 416 channel pairs available (21 of these channel pairs are reserved as control channels) with a 30 kHz spacing. Block A and B frequencies were reserved in the initial licensing by the FCC for non-wireline and wireline carriers, respectively. In addition, transmit frequencies for mobile-to-base station and for base station-to-mobile are separated by 45 MHz .
Table 16. United States Cellular Frequency Allocation Table.
United States Cellular Frequency Allocation Table |
||
Frequency Block |
Mobile-to-Base Station |
Base Station-to-Mobile |
Block A |
824.04 - 834.99 MHz |
869.04 - 879.99 MHz |
845.01 - 846.48 MHz |
890.01 - 891.48 MHz |
|
Block B |
835.02 - 844.98 MHz |
880.02 - 889.98 MHz |
846.51 - 848.97 MHz |
891.51 - 893.97 MHz |
|
4.6.4.1 Procurement Sources for Hardware and Software
Table 17 is a sample list of vendors that provide equipment and services that can assist the system engineer in the development of wireless communication.
Table 17. Wireless Equipment and Services Vendors List.
WIRELESS EQUIPMENT AND SERVICES VENDORS |
|||
BK Radio |
Stanilite |
Standard |
Maxon |
EF Johnson |
Transcrypt International |
Uniden |
Comstream |
Motorola |
Kenwood |
California Microwave |
Cylink |
AiroNet |
ATI |
KP Electronics |
----- |
For many different types of organizations, digital technology is now the solution for their two-way communication needs. Digital technology operating in the UHF/VHF range offers a variety of enhancements and benefits never before available. Mobile radios are available in a wide range of frequency bands; the choice of radio bands is determined mostly by cost, reliability, coverage distance, and type of services desire. As a rule, the lower frequencies provide a longer range service, but require larger antennas. Otherwise, many bands can be considered interchangeable. For example, with a digital system voice quality can be significantly better across more of the coverage area with little degradation as the user moves farther from the repeater. In addition, spectrum efficiency can be doubled since narrowband digital signals operate on 12.5 kHz channels instead of standard 25 kHz channels. This added spectrum efficiency is only applicable where 25 kHz channels are standard. This can have an immediate impact in urban areas with channel congestion.
4.6.5.1 Digital PCS Security Consideration
The security of a digital system is enhanced because a digital system can provide encryption protection while maintaining high quality audio. Digital offers a number of other advantages, such as integrated voice and data on one channel, along with embedded signalling features that expand the capabilities of the system.
4.6.5.2 Wireless Network Technologies
Wireless data applications usually support one of four different technologies: one-way transmission, wireless LANs, circuit switched data and two-way packet data WANs.
Wireless LAN users may use portable computers and a modem to access their desktop systems and networks when they are not too far from the office. In the future, application developers will find ways to move data through factories, schools, and institutions more efficiently. Wireless LANs trade their comparatively high bandwidth for limited coverage area and in-building or in-campus mobility.
The power of GSM lies in the robustness and flexibility it delivers to end-users. GSM is particularly viable for wireless data transmission when large file transactions are required. However, circuit-switched GSM systems are less reliable and more costly than packet-switched systems for shorter transactions requiring frequent two-way messaging such as dispatching, database inquiry, or automatic vehicle location (AVL).
Wireless data dedicated systems offer a complete range of features and flexibility designed to meet the needs of all levels of users. These systems are dedicated to wireless data, utilize highly efficient radio frequency (RF) protocols and fit Public Wireless Data Network general requirements.
Unlike circuit switched systems, a session with a user on a packet data network can be maintained without continuous access to a radio channel. When the channel is idle, other users can transmit data. When more messages are to be transmitted, a subscriber will have radio channel access without the time consuming overhead associated with establishing, breaking and reassigning a dedicated circuit between a single mobile computing device and the network infrastructure. This is achieved through contention schemes imbedded in the RF protocol which allow for maximum capacity on the system since the channel utilization is high.
4.6.5.3 Personal Messenger Wireless Modem Applications
Wireless services can provide an all-in-one communications solution with voice, paging, and e-mail messaging capabilities. Wireless services include the "smart" phone that is dual-band/dual-mode (800MHz-1900 MHz/analog-digital). These phones allow users to automatically travel between digital wireless systems and traditional analog cellular service areas and still use their phone to place and receive calls. Therefore, users can use their phone virtually everywhere cellular service is available across the U.S., Canada, and Mexico. Table 18 provides a breakdown of various wireline and wireless services that are currently available and have the potential of being available in the future.
Wireless applications fall into three general categories:
- Economical mail services are available on the network.
- The message-oriented nature of the two-way wireless network is particularly well suited to the store and forward nature of mail. The user may go in and out of range, the device may be turned on and off, or be otherwise delayed in transmission, causing traffic and time-out delays in the most session-oriented environments. The ability to reliably store and forward messages (and packets) meets the user expectations of mail.
- Mail can be routed through public networks to information providers, gateways, and other mail services.
- Built-in applications and commercial software packages already support mail. Sending a wireless message via a computer with a personal messenger wireless modem is simply a question of routing the message through a wireless service (e.g. radiomail) instead of a wireline service.
Table 18. Telecommunication Services Provided By Wireline and Wireless Technologies.
4.6.5.4 Wireless Communications Test Support
With wireless applications comes the need to characterize and maintain the quality of the signal being produced, transmitted, and retransmitted. It is the responsibility of the system engineer to ensure that the cellular equipment and or cellular service complies with established standards. Typical products used to test wireless communications include digital microwave radio test equipment, mobile/cellular radio test sets, transmitter test equipment, (modulation domain analyzers and signal analyzers) and RF channel simulator. Vendor systems and instruments are focused on either digital (i.e. GSM900, TDMA, DCS1800, etc.) or analog (i.e. FM, AM, trunking, etc.) systems.
4.6.5.5 Personal Communications Systems Engineering Development Tools
The formats for the development of an EIP, SDP, Information System Design Plan (ISDP), and Project Concurrence Memorandum (PCM) are available in Appendix A of the Long Haul Design Guide.
Acronyms
| ACR | attenuation to crosstalk ratio |
| ACUS | area common user system |
| AD | angle diversity |
| AIS | Automated Information Systems |
| ALE | automatic link establishment |
| AM | amplitude modulation |
| AMC | Army Materiel Command |
| AMI | Alternate Mark Inversion |
| AMPS | Advanced Mobile Telephone Service |
| ANSI | American National Standards Institute |
| APCO | Association of Public Safety Communications Officials |
| ARCNET | Attached Resource Computing Network |
| AR | Army Regulation |
| ASK | amplitude shift keying |
| ATA | Army Technical Architecture |
| ATIS | Alliance for Telecommunication Industry Solutions |
| ATM | asynchronous transfer mode |
| AT&T | American Telephone and Telegraph Corporation |
| AVL | automatic vehicle location |
| AWG | American wire gauge |
| BAMI | bipolar alternate mark inversion |
| BER | bit error ratio |
| bps | bits per second |
| B-ISDN | broadband integrated services digital network |
| BSTRS | Base Support Trunked Radio System |
| BTA | basic trading areas |
| C2 | Command and Control |
| C2I | Command, Control, and Intelligence |
| C3I | Command, Control, Communications, and Intelligence |
| C4I | Command, Control, Communications, Computers, and Intelligence |
| C4IEWS | Command, Control, Communications, Computers, and Intelligence, Electronic Warfare and Sensors |
| C4IFTW | Command, Control, Communications, Computers, and Intelligence for the warrior |
| Cat | Category |
| CCITT | International Telegraph and Telephone Consultative Committee |
| CDDI | Copper Distributed Digital Interface |
| CDMA | Code Division Multiple Access |
| CDPD | cellular digital packet data |
| CDS | clock distribution system |
| CJCSI | Chairman of the Joint Chiefs of Staff Instructions |
| COE | Common Operating Environment |
| CONUS | Continental United States |
| COTS | commercial off-the-shelf |
| CPE | customer premises equipment |
| CSES | consecutively severely errored second |
| CV | coding violations |
| DACS | digital access cross-connect systems |
| DARPA | Defense Advanced Research Project Agency |
| db | decibel |
| DCO | dial central office |
| DCSIM | Deputy Chiefs of Staff, Information Management |
| DDM | digital data multiplexer |
| DDS | digital data service |
| DEB | Digital European Backbone |
| DECT | Digital European Cordless Telephone |
| DII | Defense Information Infrastructure |
| DISA | Defense Information System Agency |
| DISN | Defense Information Systems Network |
| DISC4 | Director of Information Systems for Command, Control, Communications, and Computers |
| DM | depredated minutes |
| DMS | Defense Message System |
| DMU | Digital Microwave Upgrade |
| DoD | Department of Defense |
| DoDD | DoD Directives |
| DoDI | DoD Instructions |
| DOIM | Director of Information Management |
| DPAS | digital patch and access system |
| DQDB | distributed queue dual bus |
| DS | digital signal |
| DXC | digital cross-connect |
| EA-IM | Executive Agent for Information Management |
| ECCM | Electronic Counter-Counter Measures |
| EHF | extremely high frequency |
| EIA/TIA | Electronic Industries Association/Telecommunications Industries Association |
| EIP | Engineering Installation Package |
| ESCON | Enterprise System Connections |
| EKIP | Extended Korea Improvement Project |
| EMI | Electromagnetic Interference |
| EP | engineering publication |
| EMC | electromagnetic radiated interference |
| EMS | emergency medical services |
| ES | errored seconds |
| ESF | extended super framing |
| FASTBACK | AN/FRC-162 line of sight microwave radio system |
| FCC | Federal Communications Commission |
| FD | frequency diversity |
| FDDI | fiber distributed data interface |
| FDMA | frequency division multiple access |
| FED-STD | Federal Standard |
| FM | field manual |
| FM | frequency modulation |
| FO | fiber optic |
| FSK | frequency shift keying |
| FTP | Fiber and twisted pair |
| FTS-2000 | Federal Telecommunications System - 2000 |
| Gbps | gigabits per second |
| GCCS | Global Command and Control System |
| GPS | Global Positioning System |
| GSM | Global System for Mobile Communications |
| HD | hybrid diversity |
| HF | high frequency |
| HFNC | HF radio node controller |
| HS | hot standby |
| IBM | International Business Machines Corporation |
| ID | identification |
| IEC | International Electrotechnical Commissary |
| IEEE | Institute of Electrical and Electronic Engineers |
| IITS | Installation Information Transfer System |
| IM | information management |
| IMA | Information Mission Area |
| IP | Internet Protocol |
| ISDP | Information System Design Plan |
| ISO | International Standard Organization |
| ISDN | Integrated Services Digital Network |
| I-TCP | indirect transmission control protocol |
| JIEO | Joint Interoperability Engineering Organization |
| JITC | Joint Interoperability Test Command |
| JITCI | Joint Interoperability Test Command Instructions |
| JTA | Joint Technical Architecture |
| JTA-Army | Joint Technical Architecture-Army |
| JTC | Joint Technical Committee |
| JTF | Joint Task Force |
| kbps | kilobits per second |
| kHz | kilohertz |
| km | kilometer |
| LAC | local area coordinator |
| LAN | local area network |
| LEASAT | Lease Satellite |
| LEC | Local exchange carrier |
| LED | light-emitting diode |
| LD | Laser Diode |
| LF | low frequency |
| LSR | line-switched ring |
| LMR | land mobile radio |
| LOS | line of sight |
| LQA | link quality analysis |
| MAN | metropolitan area network |
| Mbps | megabits per second |
| MCEB | Military Communications-Electronics Board |
| MF | medium frequency |
| MHz | megahertz |
| mi | mile |
| MIL-STD | Military Standards |
| MM | multimode |
| MSA | Metropolitan Statistical Areas |
| MSC | major subordinate commands |
| MSK | minimum shift keying |
| MTA | major trading areas |
| mw | microwave |
| NEC | National Electrical Code |
| N-ISDN | narrow-ISDN |
| nm | nanometers |
| NNI | network node interface |
| NOSC | Naval Ocean Systems Center |
| NRZ | non-return to zero |
| ns | nanoseconds |
| NSM | network system management |
| NTIA | National Telecommunications and Information Administration |
| OC | optical carrier |
| O&M | operations and maintenance |
| OAM&P | operations, administration, maintenance, and provisioning |
| ODISC4 | Office of the Director of Information Systems for Command, Control, Communications, and Computers |
| PBX | private branch exchange |
| PC | personal computer |
| PCM | Project Concurrence Memorandum |
| PCS | personal communications system |
| PF2K | Post-FTS-2000 |
| POC | point of contact |
| PN | psuedorandom noise |
| PSR | path-switched ring |
| PSTN | public switched telephone network |
| PVC | polyvinyl chloride |
| QUALCOM | long haul cellular provider |
| QD | quadruple diversity |
| RF | radio frequency |
| RSA | Rural Service Areas |
| RZ | return to zero |
| S/A | Services/Agencies |
| SABN | Standard Automated Bill of Materials Network |
| SATCOM | satellite communications |
| ScTP | screened twisted pair |
| SD | space diversity |
| SDH | Synchronous Digital Hierarchy |
| sec/yr | seconds per year |
| SDP | System Design Plan |
| SDXC | SONET digital cross-connect X system |
| SEFS | severely errored framing seconds |
| SES | severely errored seconds |
| SF | super framing |
| SHF | super high frequency |
| SMDS | switched multimegabit data service |
| SMS | short message service |
| SONET | synchronous optical network |
| SR | Self-healing ring |
| SRA | separate reporting activities |
| SSB | single sideband |
| ST | split transmitters |
| STM | synchronous transfer mode |
| SSTP | shielded/screened twisted pair |
| STP | shielded twisted pair |
| STS | synchronous transport signal |
| T&S | timing and synchronization |
| TAFIM | Technical Architecture Framework for Information Management |
| TCP | transmission control protocol |
| TDMA | time division multiple access |
| TIA | Telecommunications Industry Association |
| TM | technical manual |
| TP | Test plan |
| TR | Test report |
| TTGR | TrueTime Global Positioning System Receiver |
| UHF | ultra high frequency |
| U.S. | United States |
| USACECOM | U.S. Army Communications Electronic Command |
| USADERMS | U.S. Army DSCS Engineering Resource Management System |
| USAISEC | United States Army Information Systems Engineering Command |
| URL | uniform resource locator |
| UTP | unshielded twisted pair |
| VHF | very high frequency |
| vs | versus |
| WAN | wide area network |
| WDM | Wavelength Division Multiplexing |
| WIN | Warfighter Information Network |
| X | cross-connect |
| yr | Year |