Traffic Aware Pilot De-contamination for Multi-Cell MIMO Systems

Traffic aware precoder/decoder design in multi-cell multi-user multiple-input multiple-output systems is considered with the objective of weighted queue minimization, where the original non-convex optimization problem is solved via successive convex approximation. Centralized pilot reuse algorithms for mitigating the pilot contamination are investigated to reflect the traffic aware optimization objective. Distinctive feature of the proposed pilot reuse algorithms is to utilize the user buffer state information jointly with the traditional large scale fading values when allocating the limited pilot resources among the served users. Numerical examples compare the performance of the proposed pilot reuse algorithms for varying number of available pilots and different traffic arrival models. The results demonstrate that significant performance gains are available when the pilot allocation strategy is designed to reflect closely the overall system optimization objective.