Throughput Analysis of a Random Access Tree Protocol for Frequency-Hopped Spread-Spectrum Packet Radio Networks

Work on the two methods of multiple access code division [using spread-spectrum (SSMA)] and collision resolution, has proceeded more or less separately. In this paper, a more combined approach is taken to the multiple access problem, by integrating the interference reduction properties of the spreading code (frequency-hopping pattern) with an algorithm for collision resolution (CRA). An approach is proposed which makes specific use of the properties of frequency-hopped (FH) signaling to aid in making the CRA efficient. A throughput analysis is performed, and a tight lower bound to the maximum stable throughput is derived. An approach is presented for evaluating an important quantity that arises in FH/SSMA systems, namely the probability of exactly m users suffering packet error given that k users transmit simultaneously. Finally, a procedure is proposed for estimating the level of channel traffic, by making use of the nature of the signaling involved.