Optimal distance estimation for the spectral efficiency of an hybrid cellular DS/SFH CDMA system

An hybrid direct-sequence/slow frequency hopping code-division multiple-access (DS/SFH-CDMA) system operating in Rayleigh fading is described and its spectral efficiency is estimated in terms of the theoretically achievable average channel capacity (in the sense of information theory) per user. The analysis covers the operation over a broadcast cellular time-varying link and leads to a simple novel closed-form expression for the optimal distance from the base station based on the maximization of the achieved spectral efficiency