Local intervehicle radio communication-multiple access and error control

A solution to the channel access and error control problems for a mobile local area radio network is investigated. For a Rayleigh-fading transmission channel in the 900-MHz band, the performance of a load-adaptive CSMA (carrier sense multiple access) access scheme in a fully connected packet radio network is analyzed. Radio reception should be possible within a 1-km range. The access scheme can adapt to the estimation of the number of active stations and is robust to estimation errors. For a given information content per packet the best error protecting block code from the families of Reed-Solomon, BCH, and CRC (cyclic redundancy check) codes is selected using the criteria of maximum throughput, minimum false decoding probability, and minimum false alarm probability. The probability of correctly receiving any message of up to 100 active stations within 300 ms is better than 99%. A certain message from 1 of 50 active stations is correctly received within 2 s with 95% probability