Dynamic signature assignment for reverse-link CDMA systems

To guarantee low correlations among user signatures in the reverse-link at the base station, we propose an adaptive algorithm to jointly update the user signatures. Making use of the wireless channel information, we iteratively reassign the spreading signature of the users with the minimum SINR (signal to interference-plus-noise ratio). As shown by simulation results, the proposed algorithm is likely to provide signatures which are orthogonal among users if the number of users is small, then multi-user detection is no longer required. When the number of users is large, the proposed algorithm still tries to maintain equal distances among user signatures, and thus improves the condition of the channel matrix and brings about an increase of capacity by up to 3-4 times, as compared to the same receivers with random codes.