Transmission Mode Selection in Cooperative Multi-Cell Systems Considering Training Overhead

Cooperative base station transmission, also known as coordinated multi-point (CoMP)transmission, is a promising technique to improve spectrum efficiency of cellular networks. however, coherent CoMP joint transmission needs huge training overhead which will reduce the effective data transmission rate. In this paper, a downlink transmission mode selection method is proposed, aiming at improving cell-edge throughput without reducing cell-center user rate. To reduce the adverse impact of the overhead, we select the following users for CoMP transmission: those can obtain significant performance gain from CoMP and those can increase the multiplexing gain. A threshold for large scale SINR is defined to find cell-edge users. An adaptive orthogonal threshold is designed for selecting partner users for the cell-edge users. Impact of the two thresholds are analyzed and performance of the proposed method are evaluated through simulations, which shows evident performance gain over both Non-CoMP and Full-CoMP systems.