This proceeding is available on CD-ROM
- San Jose, California
- Glenn Tenney, AA6ER
Paul L. Rinaldo, W4RI
- Hosted by:
- Northern California Packet Association (NCPA)
American Radio Relay League (ARRL)
10th Computer Networking Conference
September 27-29, 1991
- eXtended Mail Transfer Protocol (XMTP)
by J. Gordon Beattie, Jr., N2DSY, Andrew R. Funk, KB7UV, and Frank Warren, KB4CYC
- Abstract: The amount of store-and-forward traffic in the Amateur Radio Packet Network has increased to the point where significant optimization of the message forwarding scheme for packet bulletin board and other servers is required. The purpose of this paper is to present an enhanced message forwarding system which we call the "eXtended Mail Transfer Protocol" or XMTP which addresses this requirement. Further, an overall client/server model is included as a possible implementation enhancement to systems which plan to implement this protocol.
- A Full-Duplex 56 kb/s CSMA/CD Packet Radio Repeater System
by Mike Cheponis, K3MC and Lars Karlsson, AA6IW
- Abstract: There are no true Carrier Sense, Multiple Access with Collision Detect (CSMA/CD) systems operational in amateur radio. Full-duplex systems currently in use are actually CSMA/CA - that is, CSMA with Collision Avoidance. We describe here a system that accomplishes full collision detection with little additional system complexity compared with an ordinary full-duplex system.
- Characterization of PACSAT-1 Traffic via Downlink Monitoring
by Robert J. Diersing, N5AHD
- Abstract: This paper provides a characterization of certain aspects of PACSAT-1 downlink traffic obtained by monitoring and processing the downlink data stream. Among the aspects presented are: the proportions of the three major traffic types--broadcasting, file server, and telemetry; the interarrival times of successful file server connections; the service times for files server transactions; the AX.25 data-link level response times for file server transactions. Even though the monitoring operation is subject to various factors affecting the received block and bit error rates, the data presented here should be good approximation of the parameters of the PACSAT-1 communications system.
- Experimental Study of Shannon-Fano, Huffman, Lempel-Ziv-Welch
and Other Lossless Algorithms
by D. Dueck and W. Kinsner, VE4WK
- Abstract: Knowledge of the statistics of a source bit stream is required when selecting the most efficient statistical data compression techniques and designing the best codes. This paper presents a program called Statistical Analysis of Files (STAF) that analyzes and supplies the statistics on the frequency of occurrence table. The entropy measure is used is establishing the compression limit for statistical techniques, while the frequency of occurrence is vital in the designing of optimal code compression techniques are run-length encoding, half-byte packing, and diatomic character encoding. In the entropy report, the statistical techniques are compared with a popular adaptive non-statistical dictionary encoding algorithm, the LZW technique, to give a comparison with other methods of lossless compression on a set of benchmark files.
Recent Hubmaster Networking Progress in Northern California
by Glenn Elmore, N6GN and Kevin Rowett, N6RCE
- Abstract: This paper describes the authors' progress toward implementing a prototype digital amateur network in Northern California. A goal of the network is to provide network layer user access and high enough performance to allow a wide range of applications, both old and new, to coexist on a single network built and maintained by all users.
- Distributed Directory Services for the Amateur Packet Radio Network
by Andrew Funk, KB7UV
- Abstract: The Amateur Radio Packet Network has implemented an ad-hoc hierarchical, area-based message addressing system. In the United States these areas resolve down to states or local domain. Packet Bulletin Board Systems (PBBSs) also support a limited user directory service, implemented as the "home BBS" function. This sets the stage for relatively easily implementing a distributed directory service for the packet network.
- Specification of the AVC-R-ISA Mac Layer Protocol
by A. Giordano, I1TD, A. Imovilli, IW1PVW, C. Nobile, IW1QAP, G. Pederiva, IW1QAN and S. Zappatore, IW1PTR
- Abstract: The paper deals with the AVC-R-ISA access protocol, developed in order to maximize the one-step throughput and to solve the hidden stations problems, in a packet radio network cellular structure. After a brief description of the overall AVC-R-ISA strategy, the actual protocol machine is presented for both kinds of stations (master and slaves) that are presented in the network. A short description of the frame structure is also shown along with a brief discussion about preliminary real world performance results.
- Spectral Efficiency Considerations for Packet Radio
by Phil Karn, KA9Q
- Abstract: Radio spectrum is a lot like land; with the possible exception of the Dutch, nobody's making any more of it. So the enormous growth in demand for spectrum means that existing users, especially radio amateurs, either have to find ways to make do with less, be displaced by new users considered more worthy by regulatory agencies, or both. This paper qualitatively discusses the spectral efficiency of packet radio from several angles, ranging from antenna design, RF modulation and channel access methods to network protocols, routing algorithms and data encoding methods. Maximizing the useful carrying capacity of a spectrum assignment requires a comprehensive look at all of these factors and more. Digital techniques finally make it possible to exploit these gains, but so far amateur radio has been very slow in adopting them. I hope that this paper will stimulate some work in this direction.
- Lossless Data Compression Algorithms for Packet Radio
by W. Kinsner, VE4WK
- Abstract: This paper is a review of the important data compression methods and techniques, showing their evolution from the simplest data suppression to the modern adaptive (universal) methods. Selected lossless techniques for critically important data, requiring perfect compression and reconstruction are presented. Lossy techniques for imperfect data such as speech, images, biological signals and casual text are mentioned.
- LZW Compression of Interactive Network Traffic
by Anders Klemets, SM0RGV
- Abstract: This paper summarizes some aspects of data compression and describes how it can be used to increase the throughput of a computer communications link. The popular LZW algorithm is studied in detail, and special consideration is given to the problems that arise when using LZW to compress interactive traffic. An LZW implementation for the KA9Q Internet package for compression of interactive data is presented. Finally, the algorithm used in this implementation is compared to the V.42bis modem data compression standard.
- Proposed Design and Strategy for a Radio Direction Finding Network Using Doppler Antennas, Packet, Spread Spectrum, and Transmitter Signatures by Digital Signal Processing
by Andrew J. Korsak, Ph.D., VE3FZK/W6
- Background: Radio Direction Finding (RDF), also commonly referred to simply as DF, has been around for a long time, pretty well ever since radio began. For serious needs such as locating spies during war and malicious or inadvertent interference, some very sophisticated and expensive equipment has been applied. Amateurs have enjoyed the sport of "fox hunts," or "T-hunts," as they are frequently called, on a lesser scale. Small, isolated groups of hams have been experimenting with DF equipment and techniques of generally much lower quality than in the professional environment. This generalization applies to most aspects of amateur radio, of course, where cost by far outweighs other limiting factors that professionals can afford to trade off.
- Design and Implementation of CLEP Speech Processing System
by A. Langi, VE4ARM and W. Kinsner, VE4WK
- Abstract: This paper presents a design and implementation of a signal processing system for telephone-quality speech transmission through a low bit-rate channel, such as packet radio, at times as low as 4.8 kbit/s in either real-time or off-line mode. The system compresses speech signal down to 4.8 kbit/s using the code-excited linear predictive (CLEP) coding scheme adapted from the U.S. Federal Standard FS-1016. The system implements the CELP scheme using a floating-point digital signal processor (DSP) to perform real-time, interactive (full- or half-duplex) or fast off-line network-based applications. The system is implemented in a low-cost personal computer (PC) equipped with a TMS320C30 evaluation module (EVM).
- Digital Networking With the WA4DSY Modem - Adjacent Channel and Co-Channel Frequency Reuse Considerations
by Ian McEachern, VE3PFH
- Abstract: The explosion of digital communications in the world and the continued growth of amateur packet radio, networking with high speed modems is becoming a reality. The Dale Heatherington WA4DSY modem has given the Amateur Radio world the means of implementing the high speed networks with a 56 kb/s Minimum Shift Keying (MSK) modem. however, little is known about the performance of the modem when it is closely spaced, in frequency and proximity, with wide band and narrow band carriers. This paper investigates the performance of the WA4DSY modem with adjacent and co-channel interference for the purpose of providing tools to network planners, frequency coordinators and average users, for use in planning and implementing high speed digital networks.
- The 56 kb/s Modern as a Network Building Block: Some Design Considerations
by Barry McLarnon, VE3JF
- Abstract: In response to the now-famous cry of "Where is my high-speed RF?" Dale Heatherington WA4DSY introduced his 56 kb/s modem design to the packet community in 1987. Four years later, this breakthrough development has yet to make the major impact on the amateur packet networking world that many of us anticipated when it was introduced. We begin by examining some of the reasons why this is so, and then describe several of the possibilities for deploying the modem in the amateur packet radio network. It is the author's opinion that this modem is a versatile building block which can serve a multitude of roles in the network; if this article helps to stimulate more interest in pursuing them, then it will have served its purpose.
- Multi-Drop KISS Operation
by Karl Medcalf, WK5M
- Abstract: John Wiseman (G8PBQ) has developed a multi-drop KISS protocol, allowing several TNCs to be connected to a single serial I/O port while operating KISS mode.
The Shape of Bits to Come (a108.zip 156K)
by James Miller, BSc, G3RUH
- Abstract: This tutorial article is about bits, about bandwidth and about control of both. Lately a number of expressions have crept into amateur radio data transmission, creating both interest and puzzlement. What, for example, is the "raised cosine modulation" used on microsats AO-16/18/19? And what is the RSM-8 on Rudak/AO-21? What PSK modulation does Fuji-20 use? Come to that, what is PSK or BPSK? read on.
- The Ottawa Packet Interface (PI): A Synchronous Serial PC Interface
for Medium Speed Packet Radio
by Dave Perry, VE3IFB
- Abstract: This paper describes the design and implementation of a synchronous serial interface card using DMA for IBM PC compatible computers for use in amateur packet radio applications.
- Clover II: A Technical Overview
by Raymond C. Petit, W7GHM
- Abstract: The CLOVER-II four tone-pulse signal, methods of synchronization, control and data modes, Reed-Solomon coder, and transmission protocols are described.
- Improving the Packet Mail Transfer System
by Brian B. Riley, KA2BQE
- Introduction: The current amateur packet radio message transfer system runs extraordinarily well in view of a myriad of conflicts, mistakes, equipment failures, et al. that plague it every hour of every day. The volume of traffic is rising almost exponentially. It could reach critical mass and 'break' the system before technological solutions can be put into place. There are, however a number of things we can do within the constraints of current software and facilities to relieve much of the pressure and streamline the system for the future. Beyond that, there are several things that the codesmiths of the packet BBS world could implement reasonably quickly to further alleviate the problems.
- GUI Packet
by Keith Sproul, WU2Z and Mark Sproul, KB2ICI
- Abstract: In the 1990's the popularity of Command Line interfaces on personal computers is rapidly fading in favor of Graphical User Interfaces (GUI) on most platforms. A graphical environment using windows, icons and mice has been available on the Macintosh since 1984. It has also been available on several other computers for many years. Even computer industry insiders were surprised by the headlong rush to Microsoft Windows by owners of IBM-PCs and clones. Surely the time for packet radio to respond to the overwhelming preference of the majority of computer users is long overdue. It's high time we had a Graphical User Interface that runs over the air-waves! The author has had a packet radio Call Book server working on the air for over a year which can be accessed with normal terminals using off-the-shelf packet software. Users can also connect to it with a GRAPHICAL USER INTERFACE and get access to the same Call Book information, but with a slick GUI instead of the Command Line interface!
- NOS Command Set Reference
by Ian Wade, G3NRW
- Abstract: This paper contains details of all the commands to be found in the following KA9Q TCP/IP Network Operating System (NOS) packages: KA9Q/G1EMM: KH113016 (v1.6) (Nov 1990) and KA9Q/PA0GRI: 910618 (v1.7a) (Jun 1991).
- Higher Speed Amateur Packet Radio Using the Apple Macintosh Computer
by Doug Yuill, VE3OCU
- Abstract: This paper will discuss higher speed amateur packet radio experiments conducted with the Apple Macintosh computer and the WA4DSY radio modem. In particular, the results of using two different hardware/software combinations will be explored. The first combination uses KA9Q's NET/Mac program with a modified Pac-Comm TNC-2; the second combines Intercons TCP/Connect II (tm) with the Gracillis PackeTen NOS in a box, a stand-alone IP switch.