The low-cost packet radio

Abstract

Research on packet switched radio networks requires reconfigurable testbeds with large numbers of readily deployable radios. This motivated the development of a small, low-cost packet radio (LPR) with the flexibility to support extensive network experiments, and to be amenable to tailoring to specific end-use applications. The LPR incorporates a digitally controlled direct sequence minimum shift keyed spread-spectrum radio and a microprocessor-based packet switch. Code changeable surface acoustic wave (SAW) matched filtering provides processing gain at burst symbol rates of 100k and 400k symbols per second in the presence of interference. Coherent recursive integration enhances synchronization performance, provides synchronous detection of the data, and serves the adaptive multipath accumulator. Forward error correction utilizing convolutional encoding and sequential decoding is incorporated at four different code rates for both burst symbol rates. The microprocessor runs the networking software. Requirements, design, and performance data for the LPR engineering model are presented.