A novel quantized time‐domain compressed feedback scheme in coordinated multipoint LTE‐advanced systems

Abstract

Coordinated Multi-Point technique has attracted much attention for its promising potential on improving spectral efficiency. However, in frequency division duplexing systems, significant channel state information (CSI) mismatch and huge feedback overhead greatly limit its performance. Within state of the art feedback schemes in which channel matrix are fed back over subcarriers, the feedback overhead is too large, and the achieved network gain is also limited. In this paper, we exploit the channel sparsity in time-domain and propose an quantized time-domain compressed feedback (QTDCF) scheme. For the sake of performance evaluation, two conventional feedback schemes are compared with our scheme. Rate gap between rate with perfect CSI and actual rate with erroneous CSI is used as the performance evaluation metric. A theoretic upper bound on the rate gaps, with respect to the total feedback overhead, is also derived for our scheme. Furthermore, considering the asymmetry characteristic of the global channel, an optimal bit allocation strategy among all cooperating cells is designed for our proposed QTDCF scheme. The proposed strategy is based on the branching and bounding theory with integer constraints on bits allocated for quantizing each channel coefficient over subcarriers or channel taps. Finally, simulation results show that our scheme can significantly reduce the feedback overhead and greatly improve the CSI reconstruction quality compared with existing feedback schemes.

Energy Aware Media Access Algorithm at the Presence of Channel State Information Error in Wireless Sensor Networks

“…To perform very well, MWS needs to know the correct channel state information from the network whole. But in practical technologies, it is very hard if not impossible to extract perfect knowledge of channel state conditions [6,7]. The misbehavior caused by MWS under false channel state information is less studied in the literature.…”

“…Now, as a penalty function, the estimation of energy consumption per successful packet transmission is added to the both sides of equation (6).…”

“…While the size of packet queues are commonly available to the algorithm by message passing, CSI could be error prone due to slow and fast fading channel environment. Indeed, perfect knowledge of channel state conditions is a very strong assumption in practical technologies [6,7]. While the throughput optimality of MWS algorithm and its promising delay characteristics are well studied under presence of trust able CSI, the impact of channel estimation errors on the performance of MWS is less studied in the literature.…”

A resource efficient scheme for backhaul‐constrained coordinated multipoint cellular networks

“…A novel bandwidth allocation scheme is proposed in Reference 36 for mobile traffic management and improved convergence time, wherein X2 traffic is prioritized over other types of traffic in optical backhaul based 5G systems. In Reference 37 authors propose a quantized compressed feedback scheme to reduce the feedback overhead by exploiting channel sparsity in the time domain. In 3GPP Rel‐12, development of CoMP for non‐ideal backhaul (such as X2) has been considered 38 .…”

Dynamic Coordination Architecture and Mobility Management for Next Generation Cooperative Cellular Networks

“…The coordinated eNBs exchange the received CSI and/or data among them providing services to the UE. Accordingly, the CSI feedbacks increase the signaling overhead into the networks and feedback latency significantly that requires high bandwidth backhaul [14,15,18,19,20].…”