Performance of Pilot-Assisted Channel Estimation without Feedback for Broadband ANC Systems Using OFDM Access
Recently, broadband Analog Network Coding (ANC) has intensively been studied due to its potential to increase the network capacity by exploiting the broadcasting nature of the wireless channel. In this paper, the authors propose a Pilot-Assisted Channel Estimation (PACE) scheme without Channel State Information (CSI) feedback from the relay for broadband ANC using orthogonal frequency-division multiplexing. In the first time slot the users transmit their respective pilots to the relay and in the second time slot the relay simply amplifies and forwards the received pilot signals to both users. Each user can then estimate all the CSI it needs for self-information removal and coherent signal detection, without requiring any feedback of the CSI estimates from the relay.