Performance of PN/FH hybrid spread spectrum systems against partial-band noise interference

Hybrid PN/FH spread spectrum systems are of great potential interest for future satellite communications. In this paper, the performance of these hybrids, characterized by the fractional PN spread bandwidth (beta) and the ratio of hop rate to information symbol rate (L), is calculated for optimum partial-band Gaussian noise interference. Chernov bounds on bit error rate are obtained which are jointly minimized over the communicators, strategy and maximized over the interferor's. The new results merge smoothly with related results in literature. It is found that when the hop rate has been optimally selected for fixed beta, the bit SNR required for a given performance level is primarily determined by the frequency hopping and is relatively insensitive to beta. At hop rates below optimum, the contribution of PN spread can be substantial, but for hop rates above optimum, performance becomes essentially independent of beta. Design curves are presented showing how a given performance can be obtained at different bit SNRs with various combinations of beta and L.