Interference Avoidance and Power Control for Uplink CDMA Systems

The paper presents an algorithm for joint codeword adaptation and power control in which users in a CDMA system so as to achieve a specified set of target signal-to-interference plus-noise ratios (SINR). Codeword adaptation is based on greedy interference avoidance which decreases the effective interference seen by users and is followed eventually by power adjustment if the resulting SINR after codeword adaptation is below the specified target. Provided that the targets are admissible the algorithm yields a codeword ensemble and power allocation that satisfy a water filling distribution. Numerical examples which illustrate the algorithms are also included.