Individual Channel Estimation for AF-Based Relaying Systems Using In-Band Pilots
Dou Gaoqi, He Xianwen, Ran Deng, Gao Jun, Zhongpu Cui · IEEE Communications Letters · 2016
In amplify and forward cooperative relaying system, the knowledge of individual channel state information (CSI) is essential for coherent decoding and optimal design. To assist in the estimation of the individual channels, we proposed an in-band pilot strategy, where some cooperative data at the relay are discarded to insert pilots that can be utilized to estimate the relay to destination link. The new cooperative strategy implies that relay not only helps the source to transmit cooperative data, meanwhile, assisting the destination to acquire the individual CSI at the cost of cooperative information. Although some useful data are lost due to insertion of in-band pilots, the detection performance can be maintained with a simple iterative reconstruction method. Furthermore, if the direct link is available, the received signals from both the source and the relay can be combined to achieve spatial diversity. Simulation results are presented to assess the performance of the proposed schemes.