Coordinated Multi-Point transmission with imperfect channel knowledge and other-cell interference

Coordinated Multi-Point (CoMP) transmission is a promising technique for LTE-Advanced systems, especially due to the enhanced throughput performance of cell edge users. In this paper, we investigate joint transmission (JT) and coordinated beamforming (CBF) with quantized and delayed feedback, and we derive ergodic rate and outage probability expressions assuming large-scale fading (pathloss), small-scale Rayleigh fading, and other-cell interference (OCI). Furthermore, we employ a moment matching technique that approximates the distributions of the received desired and interference signals with Gamma distributions as a means to facilitate analysis and simulation. The performance of CoMP transmission is quantified and compared with non-cooperative transmission, and operating regions in which CoMP gains are more pronounced are provided. The versatility of the proposed approximate framework enables us to identify key system parameters, such as feedback resolution, pathloss, and transmit SNR for which CoMP becomes a judicious choice of transmission strategy.