Cross-layer rate allocation in CDMA systems with imperfect successive interference cancellation

In CDMA systems with imperfect successive interference cancellation (SIC), the numbers of possible rate modes and decoding orders grow exponentially with the number of users. How to allocate rates in order to maximize the system utility is an NP problem, which involves the joint optimization of rate allocation at the link layer and decoding order adjustment at the physical layer, and thus the cross-layer rate allocation should be considered. This paper proposes an efficient cross-layer rate allocation algorithm for addressing this NP problem. The proposed algorithm can be decomposed into two layers: the inner layer examining method to adjust the decoding order and quickly examine the feasibility of rate modes; the outer layer updating scheme to efficiently update rate modes based on the particle swarm optimization (PSO) algorithm. We conduct extensive simulation experiments, and the numerical results show that our proposed algorithm outperforms the existing algorithms based on the greedy algorithm.