Performance enhancement for CoMP based on power allocation and a modified ZF-THP

Base station joint transmission techniques based on QR decomposition(QRD) and Tomlinson-Harashima precoding (THP) can improve the cell-edge user BER performance. But the large spreading of the subchannel gains may degrade the performance severely. In this paper, an equal rate power allocation (ERPA) strategy and a modified zero-forcing(ZF) THP (M-ZF-THP) technique are introduced which can equalize the subchannel quality and improve the performance of the downlink coordinated multi-point transmission and reception (CoMP). Both techniques are based on the theorem that optimal bit-error-rate performance of the multi-antenna system can be achieved when spatial pipes have the same quality. “Best-first” ordering algorithm is used in M-ZF-THP to enhance the performance. Simulation results show that our proposed schemes are superior to QRD and ZF-THP based algorithms.