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Selected Areas in Communications, IEEE Journal on

Issue 3 • Date May 1985

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Displaying Results 1 - 13 of 13
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • [Back cover]

    Page(s): 0
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    Freely Available from IEEE
  • Guest Editorial

    Page(s): 397 - 398
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    Freely Available from IEEE
  • ALAN: A (Circuit-Switched) Local Area Network

    Page(s): 427 - 430
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    Our view is that people (that is, programmers and general computer users) tend to work together in small groups, where information and resources are shared freely within a group. Most interactions occur within the group (called a cluster)-sending messages, exchanging data, sharing a printer. Communication outside the cluster-sending mail to someone in another group or using a large number cruncher-is comparalively rare. Under this hypothesis, it is advantageous to optimize and simplify interactions within the group. This paper describes our attempt to design a cluster network based on a nonblocking crosspoint switch, which we call ALAN (a local area net). ALAN clusters are star-connected-with intelligent workstation nodes (PC's) at the points of the star, and the ALAN switch at the center. View full abstract»

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  • The Application of Digital Broadcast Communication to Large Scale Information Systems

    Page(s): 457 - 467
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    A new type of information system is described that combines personal computers, broadcast data communication, and bidirectional communication. The system is designed to use broadcast communication whenever possible to deliver information to personal computers, which are used for data storage, indexing, and retrieval. This paper starts with an overview of the system, and then discuss the problem of reliable digital broadcast communication in some detail. A parameterized broadcast protocol is described, and we show how to choose protocol parameters based on observed channel error characteristics. A flexible encryption-based protection system is included in the protocol. We discuss the implementation of the system on contemporary personal computers. A broadcast system based on these ideas is now operating in Boston area homes. View full abstract»

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  • The Desktop Computer as a Network Participant

    Page(s): 468 - 478
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    A desktop personal computer can be greatly extended in usefulness by attaching it to a local area network and implementing a full set of network protocols, just as one might provide for a mainframe computer. Such protocols are a set of tools that allow the desktop computer not just to access data elsewhere, but to participate in the computing milieu much more intensely. There are two challenges to this proposal. First, a personal computer may often be disconnected from the network, so it cannot track the network state and it must be able to discover and resynchronize with that state very quickly. Second, full protocol implementations have often been large and slow, two attributes that could be fatal in a small computer. This paper reports a network implementation for the IBM Personal Computer that uses several performance-oriented design techniques with wide applicability: an upcall/downcall organization that simplifies structure; implementation layers that do not always coincide with protocol specification layers; copy minimization; and tailoring of protocol implementations with knowledge of the application that will use them. The size and scale of the resulting package of programs, now in use in our laboratory for two years, is quite reasonable for a desktop computer and the techniques developed are applicable to a wider range of network protocol designs. View full abstract»

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  • Packet Radio in the Amateur Service

    Page(s): 431 - 439
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    During the past several years there has been much activity in the development of networking hardware and software for personal computers. At the same time the amateur radio community has been equally active in the development of networking equipment and procedures especially suited for radio circuits. Although the initial efforts have been with terrestrial circuits, experimentation with and development of satellite-based systems is well underway. While we are aware of the many commercial and government organizations active in specialized packet radio systems, our goal is to establish radio networks with inexpensive equipment that is within reach of a large number of individuals with limited budgets. This article will provide a brief history of hardware, software, and protocol development activities as well as a description of amateur packet radio operations. Also discussed are satellite-based operations and development efforts. These include AMSAT-OSCAR-10 and UoSAT-OSCAR-11, currently operating in orbit, and PACSAT, JAS-1, and Phase 3-C, in the design and construction phases. View full abstract»

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  • SNA Networks of Small Systems

    Page(s): 416 - 426
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    This paper discusses SNA/LEN, a possible extension of Systems Network Architecture intended to allow peer, dynamic, and easy to use networking functions for a variety of node sizes down to and including the new generation of personal computers. After reviewing the special requirements posed by small systems and the need for including them as equal partners in networks, the LEN architecture is described. This is done by following a sequence of steps that begin when a logical resource at some node that may not yet be part of the connectivity of an existing network requests a session with a remote logical resource of unknown location. After connectivity with the preexisiting network is established, directory services locates the remote object, route selection services determines the preferred path, a session is activated, and deadlock-free flow control assures a useful flow of data. Preliminary quantitative results from an LEN prototype are presented. View full abstract»

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  • Personal Computer Communications Via Ku-Band Small-Earth Stations

    Page(s): 440 - 448
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    This paper describes recent developments in geosynchronous satellite communication with special emphasis on data communication using small inexpensive Earth stations (small-Earth stations or microstations). Recent innovations in design, impacts of regulatory codes and decisions, and an illustrative system design example are all examined. Attention is directed to systems using radio frequency (RF) carriers in theKu-band (14/12 GHz). At some or all of these frequencies terrestrial users are generally considered as secondary to users of fixed satellite services. Because of this relative freedom from terrestrial interference concerns, installation ofKu-band small-Earth stations can be made relatively free of regulatory involvement and coordination procedures. The basic equations governing the noise and interference terms entering link margin calculations are presented. A design example is given, detailing one type of system of practical importance. View full abstract»

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  • Personal Computer Communications Via Telephone Facilities

    Page(s): 399 - 407
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    Communication from terminals to other terminals and to computing service systems has been an important aspect of data communications since the early 1960's. When personal computers arrived on the scene, in the 1970's, the use of telephone facilities and modems for communications was a natural extension of existing technology. Now, however, many modems have "intelligence" and can be controlled from their electrical interface, communication software is available to facilitate the use of a modem and coordinate the communication process, and there are many uses for personal computer communications. Some of the hardware, software, and computing services for personal computer communications are discussed in this paper. View full abstract»

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  • Distributed Processing Involving Personal Computers and Mainframe Hosts

    Page(s): 479 - 489
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    This paper surveys some of the issues involved in building useful distributed systems involving PC's and hosts. Alternative communications techniques for micro-mainframe communication are compared. The point of view is presented that the PC user should be provided with a unified view of the heterogeneous distributed system to which he is connected. The proposed method is to formalize the notion of a service request and provide distributed services by function shipping service requests to remote nodes able to provide the service, e.g., personal computers will ship requests which they cannot satisfy locally to hosts on the network. Providing a unified view of data which allows PC application programs to access files on mainframes is an example of a service which can be built by intercepting and shipping service requests. Examples from current IBM products are used to illustrate approaches. The views presented are the authors' own, based on systems research in progress at the IBM Thomas J. Watson Research Center. View full abstract»

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  • Cost-Effective Data Communications for Personal Computer Applications Using Micro Earth Stations

    Page(s): 449 - 456
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    The reduction in cost of computer processing and storage that led to personal computers has stimulated a need for comparable reduction in telecommunication costs to connect distributed personal computers to central computer facilities. A reexamination of the underlying technical options open to terrestrial and satellite telecommunications alternatives illustrates the advantages of satellite networks for data communication. The principles are illustrated with a description of a particular satellite network technology utilizing user-premises micro Earth stations that are cost-effective for use as accessories to personal computers or equivalent work stations. View full abstract»

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  • Broad-Band Personal Computer LAN's

    Page(s): 408 - 415
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    Broad-band technology provides several advantages for personal computer local area networks (PC LAN's) including mature readily available transmission technology, large total bandwidth, support for multiple services, and cost-effective expansion from very small to very large systems. This paper presents an overview of basic broad-band technology, hardware, software, and protocols needed for PC LAN's. Gateways and network management are also considered. Recent PC LAN products are compared, with a more detailed case study of the PC LAN developed by IBM and Sytek. View full abstract»

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Aims & Scope

IEEE Journal on Selected Areas in Communications focuses on all telecommunications, including telephone, telegraphy, facsimile, and point-to-point television, by electromagnetic propagation.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Muriel Médard
MIT