Probability of Multiple Correct Packet Receptions in a Multireceiver Frequency-Hopped Spread-Spectrum System.

摘要

In this report we develop exact expressions and approximations for the probability of exactly l correct packet receptions in a group of m receivers, given that k packets are transmitted simultaneously from users employing frequency-hopping spread-spectrum (FH/SS) and Reed-Solomon (RS) coding. This quantity is essential for the design and performance evaluation of multiple-access protocols in spread-spectrum packet radio networks. The evaluations are carried out for MFSK modulation with noncoherent demodulation and various types of RS minimum-distance decoding with erasures and/or errors decoding. Packet synchronous FH/SSMA systems that are hop-synchronous or hop-asynchronous are considered. The exact expressions developed have computational complexity that grows exponentially with m, thus making their evaluation for large m prohibitive. In light of such difficulties, two approximations are considered: one based on Gaussian multivariate distributions with linear computational requirements in m and k, and another based on the assumption of independent receiver operation (IROA), which has minimum computational complexity. Extensive comparisons of the approximations with the exact results establish their validity over different ranges of the system parameters. (Author)