Adaptive coordinated multi-point transmission based on delayed limited feedback

This paper studies the capacity performance of coordinated multi-point (CoMP) downlink transmissions based on limited feedback. We consider both path loss effects and channel imperfections including feedback delay and quantization error. Closed-form expressions are derived to characterize ergodic achievable rates for joint processing (JP) and coordinated beamforming (CBF) techniques, respectively. According to the derived expressions, an adaptive transmission strategy to switch between JP and CBF is proposed to maximize cell throughput. Simulation shows the CBF scheme is preferred at medium SNR with varying switch points jointly determined by the feedback size, delay, and locations of CoMP users.