Mode selection for CoMP transmission with quasi timing synchronization

This paper proposes a mode selection strategy to improve the spectral efficiency for coordinated multi-point (CoMP) transmission with quasi timing synchronization. Upper bounds of average achievable rate for different CoMP transmission modes, such as coordinated beamforming (CB) and joint processing (JP), are derived. According to these upper bounds, we find that the performance of JP has been significantly degraded by quasi timing synchronization, while the performance of CB remains unchanged. The proposed mode selection strategy can switch CoMP transmission mode between CB and JP adaptively to maximize the average achievable rate. In addition, the proposed mode selection strategy requires low extra overhead and has ease of implementation. Simulation results show that the proposed mode selection strategy outperforms single mode CoMP transmission when just quasi timing synchronization is achieved.