Investigation on improvement in channel estimation accuracy using data signal muting in downlink coordinated multiple-point transmission and reception in LTE-Advanced

Accurate channel estimation for multiple cells is essential in downlink coordinated multi-point (CoMP) transmission/reception. Therefore, this paper investigates a technique to improve the channel estimation for downlink CoMP in Long-Term Evolution (LTE)-Advanced. Particularly, the performance of data signal muting, i.e., muting data signals that collide with the channel state information reference signal (CSI-RS) of the neighboring cell, is evaluated considering various CoMP schemes and intra-eNodeB and inter-eNodeB CoMP scenarios. In a multi-cell link level simulation, coordinated scheduling and coordinated beamforming (CS/CB) CoMP is employed. The simulation results show that data signal muting is effective in improving the channel estimation accuracy and consequently the throughput performance, especially for sets of user equipment at the cell boundary. Furthermore, the tradeoff relation between accurate channel estimation by muting larger numbers of data signals and a high peak data rate, i.e., low overhead, is also investigated. It is shown that when the number of coordinated cells is set to three, the improvement in performance is almost saturated when the data signals that collide with the CSI-RSs of the other two coordinated cells are muted in a synchronized network.