Band based power control (BBPC) for MC-CDMA radio interface

This paper highlights, limitations of ECPC (Each Carrier Power Control) concept [1] - originally proposed for OFDM-DS-CDMA - when extended to MC-CDMA (Multi-Carrier Code Division Multiple Access) systems. First, its impractical signaling overhead of 80% secondly; its inability to be used as an uplink-power control mechanism. Then we propose BBPC (Band Based Power Control) as a practical alternative to ECPC for MC-CDMA systems. Unlike, ECPC that controls power on each carrier basis, BBPC assigns same power level to a band of carriers (lying within coherence bandwidth of channel). It has been shown that with a nominal performance loss, BBPC reduces the signaling overheads to 2.5% and by employing the control index estimator after de-spreading, it can be used as an uplink power control mechanism for MC-CDMA. We have used SIR (Signal to Interference Ratio) as a power control index, BER and standard deviation of power control error as performance metrics.