Spectral efficiency of multiple access techniques

The terms modulation and multiple access are used to define two entirely different matters and hence the efficiency they contribute is separable. In theory, all multiple access techniques potentially have 100% relative spectral efficiency provided that the channels are orthogonal. The paper evaluates the spectral efficiency of various multiple access techniques by considering their performance in practice. This is achieved by defining a multiple access efficiency factor which is then used to derive various mathematical equations as a function of some system parameters. Typical values for the multiple access efficiency factor for first and second generation cellular systems are presented.<>