Performance of multirate transmission schemes for a multicarrier DS/CDMA system

In this paper, two multirate transmission schemes are considered for an asynchronous multicarrier (MC) DS/CDMA system: multicode scheme and multiple processing gain (MPG) scheme. Successive interference canceller (SIC) is applied for the two multirate MC-DS/CDMA systems to cancel multiple access interference (MAI). The bit error rate (BER) of each system is obtained by analysis and simulation in a Rayleigh fading channel with perfect channel estimation. It is shown that higher rate users have smaller BER than lower rate users in both systems. It is shown that the system with multicode scheme has better performance than the system with MPG scheme for high processing gain. Also it is shown that the former has even better performance than the latter when SIC is applied.