Transmission power control techniques for the reverse link of OFDM-DS-CDMA system

A method of transmission power control (TPC) for orthogonal frequency division multiplexing direct sequence code division multiple access (OFDM-DS-CDMA), in order to compensate for power attenuation at each subcarrier, is proposed. Instead of assigning the same power levels for all-subcarriers, different transmission power levels are assigned to different subcarriers, according to the attenuation of the subcarriers. System performance, in terms of bit error rate (BER), has been evaluated by Monte Carlo simulation. The simulation results presented significant improvement; the proposed system performed much better than the system without TPC. It is shown that the each-carrier TPC performed better than all-carrier TPC, hence each-carrier TPC is more suitable for OFDM-DS-CDMA systems.