Home // International Journal On Advances in Telecommunications, volume 10, numbers 3 and 4, 2017 // View article

A Regenerative Detect & Forward Relay Transmission in Linearly Precoded MU-MIMO Downlink

Authors:
Nobuaki Shimakawa
Yasunori Iwanami

Keywords: MU-MIMO; Block Diagonalization; Eigen mode transmission; Regenerative relay; Detect & Forward

Abstract:
Recently, Multi-User MIMO (MU-MIMO) downlink system which uses multiple antennas at Base Station (BS) and accommodates multiple users with multiple reception antennas attracts much attention. In MU-MIMO downlink system, by knowing the Channel State Information (CSI) at BS, Inter User Interferences (IUI’s) among users are pre-excluded at BS. By increasing the number of transmission antennas assigned to each user, the transmission quality of each user is effectively improved. In MU-MIMO, there exists linear precoding or nonlinear precoding method, but linear precoding is considered more easily implemented and adjusted than nonlinear precoding. In this paper, we aim the coverage extension and the transmission quality improvement by using a regenerative Detect & Forward (DF) relay in MU-MIMO downlink system. We use Block Diagonalization (BD) + Eigen mode transmission (E-SDM) for linear MU-MIMO downlink scheme. By sharing the BD matrix at both BS and DF relay, the DF relay can demodulate the receive signal with the receive CSI only and can forward the detected signal to each user. At each user, the received signals from BS and DF relay are combined through bit LLR (Log Likelihood Ratio) addition to minimize the BER. With this system configuration and by employing large number of transmission antennas, we have shown the effectiveness of regenerative DF relay through simulations.

Pages: 85 to 95

Copyright: Copyright (c) to authors, 2017. Used with permission.

Publication date: December 31, 2017

Published in: journal

ISSN: 1942-2601