Joint base stations clustering and feedback bits allocation for multi-cell coordinated beamforming systems

摘要

In this study, the authors investigate the problem of maximising the mean rate in a multi-cell coordinated beamforming system considering practical delayed limited feedback and constrained backhaul. To tackle this hard problem, they first derive the analytical expression of the upper bound on the mean rate loss due to the clustered coordination and the imperfect channel feedback. Particularly, this upper bound quantitatively reveals a key tradeoff between decreasing inter-cell interference with larger base station (BS) cluster and decreasing inter-user interference with smaller BS cluster but improved channel state information accuracy. In light of this, they jointly optimise the BSs clustering and feedback bits allocation (BCFA) with the objective of minimising the upper bound on mean rate loss, which is equivalent to the problem of maximising the mean rate. Utilising the relaxation-and-rounding approach, a BSs clustering and feedback bits allocation algorithm, referred to as BCFA, is designed, which has good performance with low complexity. Finally, extensive simulation results are provided to demonstrate the advantages of the proposed algorithm.