Optimizing Processing Gain of a Cellular DS/FFH-CDMA Rayleigh Fading System

The optimization between the processing gain and the theoretically achievable average channel capacity (in the sense of information theory) per user of a constant total system's allocated bandwidth, hybrid direct-sequence/fast frequency hopping code-division multiple-access (DS/FFH-CDMA) cellular system operating in a Rayleigh fading environment, is presented. Then, the spectral efficiency is estimated in terms of the achievable average channel capacity per user, during the operation over a broadcast cellular time-varying link, and leads to a simple novel-closed form expression for the optimal processing gain value based on the maximization of the achieved spectral efficiency. Numerical results are presented to illustrate and prove the validity of the presented work.