Channel estimation errors impact on the sum rate maximisation in a JP‐CoMP transmission systems

Abstract

Cooperation between multicell base stations (BSs) is a promising technique that has the potential to mitigate inter‐cell interference (ICI) and increase data rates without sacrificing additional frequency spectrum. Classical beamforming techniques have been used to eliminate the existing ICI and improve the sum rate of downlink cooperative multiple input multiple output transmission systems. However, a perfect knowledge of the channel state information at the transmitter is needed to perform adequate beamforming such as block diagonalisation or zero‐forcing preprocessing. In practice, this is not the case due to the presence of channel estimation errors.In this paper, we consider one particular scenario of the transmission coordination among multiple cell sites, namely the joint processing coordinated multipoint transmission scheme. A joint processing coordinated multipoint is composed of several BSs that cooperate to serve a set of mobile stations (MSs) and where both BSs and MSs are equipped with multiple antennas. In the context of this transmission scenario, we model the multicell cooperative system under the presence of channel estimation errors that are often neglected but that can significantly influence the obtained results. Furthermore, we consider a general framework where the distributed power from the BSs to the MSs is not constrained to be identical. We then propose a modified version of the classical block diagonalisation and zero‐forcing beamforming to efficiently mitigate the existing ICI. Finally, we evaluate the sum rate expression of the considered cooperative system, and we propose efficient alternatives to improve it without coupling the beamforming and the power control processes. Simulation results are given to support our claims. Copyright © 2013 John Wiley & Sons, Ltd.

Cognitive radio network with coordinated multipoint joint transmission

“…21 In JP/JT, data of a user is available to the coordinating BSs and these BSs transmit the same packet simultaneously to the user. 23,24 In Abdelkefi et al, 25 the performance of CoMP technique is studied with CSI error and it is shown that error in estimating CSI can significantly influence the performance. 18 The major issues in JT technique are synchronization of distant sites, multicell channel estimation, feedback of the channel state information (CSI), synchronous exchange of user data, and JP.…”

“…18 The major issues in JT technique are synchronization of distant sites, multicell channel estimation, feedback of the channel state information (CSI), synchronous exchange of user data, and JP. 23,24 In Abdelkefi et al, 25 the performance of CoMP technique is studied with CSI error and it is shown that error in estimating CSI can significantly influence the performance. The limited capacity of backhaul connection of the coordinating the BSs is also another vital issue in implementing CoMP technique.…”

Energy-Efficient On–Off Power Control of Femto-Cell Base Stations for Cooperative Cellular Networks

“…Although the use of the incurred traffic load is reasonable in most of cases, it can be inappropriate when the cooperative transmission is used, in which multiple FBSs cooperate in data transmission to improve the performance, e.g., CoMP [27][28][29][30][31][32]. More specifically, the contribution, i.e., the throughput improvement due to the participation of the FBS in the cooperative transmission, of each FBS on the cooperative transmission has to be taken into account in order to properly decide which FBS to switch off.…”

Optimal scheduling of coordinated multipoint transmissions in cellular networks

“…The major issues in JT technique are synchronization of distant sites, multicell channel estimation, feedback of the channel state information (CSI), synchronous exchange of user data, and joint processing. () In Abdelkefi et al, the performance of CoMP transmission technique is studied with CSI error and it is shown that error in estimating CSI can significantly influence the performance. The limited capacity of backhaul connection of the coordinating BSs is also another vital issue in implementing CoMP transmission technique.…”