Power control scheme with signature sequence adaptation for DS-CDMA systems

In this paper, we investigate practical issues for implementing power control together with signature sequence adaptation in direct sequence code division multiple access (DS-CDMA) systems. A practical decentralized power control algorithm with sequence adaptation is proposed. In this algorithm, each user independently and simultaneously implements power control and alters his/her signature sequence according to the information collected from the channel (simply by sampling the received signal). No information from the other users is required. A simplified version of the algorithm with low complexity is also developed in this paper. Simulations show that with a small number of samples per iteration, our decentralized algorithms with matched filters perform much better than power control with minimum mean square error (MMSE) receivers only.