The Value of Channel Prediction in CoMP Systems with Large Backhaul Latency

The potential of coordinated multi-point (CoMP) transmission in providing high spectral efficiency for cellular systems largely depends on the channel quality at the cooperated base stations. In this paper, we investigate whether channel prediction is useful for downlink CoMP systems with backhaul latency in time-varying channels, where both the centralized and decentralized CoMP joint processing (CoMP-JP) as well as the CoMP coordinated beamforming (CoMP-CB) are considered. Toward this goal, we resort to large system analysis with large number of transmit antennas to derive closed form expressions of the average per-user rate of the CoMP systems, when predicted or estimated channels are employed for downlink precoding. By comparing with Non-CoMP systems, we find that channel prediction provides much higher performance gain over channel estimation for CoMP systems, depending on the strategy of the cooperation and the user location. As a result, CoMP systems can perform fairly well for mobile users even under the large backhaul latency, if channel prediction will be used instead of channel estimation. Simulation results are provided to validate our analysis.