This work presents joint iterative power allocation and interferencesuppression algorithms for spread spectrum networks which employ multiple hopsand the amplify-and-forward cooperation strategy for both the uplink and thedownlink. We propose a joint constrained optimization framework that considersthe allocation of power levels across the relays subject to individual andglobal power constraints and the design of linear receivers for interferencesuppression. We derive constrained linear minimum mean-squared error (MMSE)expressions for the parameter vectors that determine the optimal power levelsacross the relays and the linear receivers. In order to solve the proposedoptimization problems, we develop cost-effective algorithms for adaptive jointpower allocation, and estimation of the parameters of the receiver and thechannels. An analysis of the optimization problem is carried out and shows thatthe problem can have its convexity enforced by an appropriate choice of thepower constraint parameter, which allows the algorithms to avoid problems withlocal minima. A study of the complexity and the requirements for feedbackchannels of the proposed algorithms is also included for completeness.Simulation results show that the proposed algorithms obtain significant gainsin performance and capacity over existing non-cooperative and cooperativeschemes.
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