Analysis of Sparsely-Spread CDMA via Statistical Mechanics

In this paper, we present a framework of statistical-mechanics-based analysis of sparsely-spread CDMA systems. The sparsely-spread CDMA can be considered as a simple mathematical model for various types of CDMA such as frequency-hopping (FH) CDMA and time-hopping (TH) CDMA. After presenting a general framework of analysis by the replica method, we analyze the system with Gaussian inputs, on the basis of the effective medium approximation. We obtain the multiuser efficiency and the spectral efficiency of the sparsely-spread CDMA system, and evaluate its performance in comparison with the densely-spread CDMA system.