In this paper, we consider dynamic precoder/decorrelator optimization formultimedia streaming in MIMO interference networks. We propose a trulycross-layer framework in the sense that the optimization objective is theapplication level performance metrics for multimedia streaming, namely theplayback interruption and buffer overflow probabilities. The optimizationvariables are the MIMO precoders/decorrelators at the transmitters and thereceivers, which are adaptive to both the instantaneous channel condition andthe playback queue length. The problem is a challenging multi-dimensionalstochastic optimization problem and brute-force solution has exponentialcomplexity. By exploiting the underlying timescale separation and specialstructure in the problem, we derive a closed-form approximation of the valuefunction based on continuous time perturbation. Using this approximation, wepropose a low complexity dynamic MIMO precoder/decorrelator control algorithmby solving an equivalent weighted MMSE problem. We also establish the technicalconditions for asymptotic optimality of the low complexity control algorithm.Finally, the proposed scheme is compared with various baselines throughsimulations and it is shown that significant performance gain can be achieved.
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