On CI/MC-CDMA System Design with Improved Receiver Performance

This paper proposes a carrier interferometry/multicarrier code division multiple access (CI/MC-CDMA) system that simultaneously supports variable data rate transmission. High data rate transmission uses all subcarriers, while low data rate transmission through the alternate use of subcarriers and odd-even splitting of Cl codes. The cross-correlation values among the different code patterns are reduced through proper setting of phase shift for the CI codes. The contributions of the work are of two folds: a dynamic user allocation algorithm for capacity improvement followed by improved receiver performance through the weighted subcarrier parallel interference cancelation (w-SCPIC). The use of neural network (NN) determines and updates the weight factors for w-SCPIC. Simulation results show that dynamic user allocation maintains acceptable values of bit error rate at much higher user capacity due to this w-SCPIC scheme. Simulation results also show that dynamic user allocation improves peak-to-average power (PAPR) reduction compared to fixe user allocation.