Reduced Complexity Algorithm for Spreading Sequence Design

This paper describes a novel gradient descent algorithm for the constrained optimization of spreading sequence design in the uplink of CDMA systems that use codeword adaptation. We prove that the proposed algorithm converges to the optimal sequence. In addition, the paper demonstrates the convergence of the parallel distributed optimization which is confirmed by simulations. Parallel optimization ensures faster convergence and thus reduces computational load. The performance of the parallel algorithm is improved as the number of active users increases.