Performance comparison of frequency-hop spread-spectrum multiple-access networks using different modulation orders

Abstract

The main concern of this paper is to estimate the symbol error probability of asynchronous FHSS multiple-access networks through Monte Carlo simulations and use this estimate to compare more accurately the performance of FHSS multiple-access networks with different modulation orders M. The author concentrates on systems transmitting one M-ary (M/spl ges/2) orthogonal FSK modulated symbol per hop with noncoherent demodulation. The usual practice is to upper bound the probability of symbol error when a hop is hit by K'/spl ges/1 other users by (M-1)/M (or 1.) Work on the derivation of accurate approximations to this probability when M=2 has indicated that the aforementioned bound not only gives excessively pessimistic results but may also lead to wrong trade-off decisions. In this paper, using the simulated values for the error probability it is shown that the same is true for M>2. Also by employing a normalized throughput measure that takes into account the bandwidth expansion associated with the modulation order M>2, it is shown that there exists an optimum value of M for a given bandwidth that should be used to obtain the largest possible network throughput for a given bandwidth. Simulations and throughput results are also given when the signals from the active users in the network suffer from independent Rayleigh fading.