Sum-Rate Evaluation of Multi-User MIMO-Relay Channel

Abstract

In this paper, the multiuser multiple-input multipleoutput (MU-MIMO) relay channel is investigated, where the source node provides multi-beams to multi-users via a multi-antenna relay node. In this scenario, linear processing matrix at the relay node is designed around block diagonal (BD) scheme to improve the system sum-rate. Compared with the traditional linear processing matrix with zero-forcing (ZF) scheme at the relay node, the proposed matrix based on BD scheme can not only eliminate the multiuser interference to the same extent as the ZF scheme, but also realize optimal power allocation at the relay node. Numerical simulations demonstrate the BD scheme outperforms the ZF scheme and can significantly improve the sum-rate performance.

Joint subchannel matching and power allocation for the MIMO broadcast relay channel

“…The noise variances are assumed to be σ 2 1 = σ 2 2 = 1. We compare the sum rate performance of the proposed joint matching and power allocation scheme with various schemes as P s = P r varies, including the scheme in [1]. The sum-rate is averaged over a large number of channel realizations.…”

“…From (6), we can observe that K parallel subchannels arise via the use of transceiver architecture (5). A similar architecture has also been developed in [1] for the case when destinations have multiple receive antennas. Main contribution of this letter is to take permutation of the first hop subchannels into consideration, leading to the following joint optimization problem of the subchannel matching and power allocation:…”

“…Assuming that each destination has a single antenna, the authors in [2] proposed various transceiver architectures, where the source node adopts a nonlinear processing so called dirty paper coding and the relay node uses a linear processing. More practical linear processing schemes both at the source and the relay was considered in the work [1], where with the use of singular value decomposition (SVD) and block diagonalization (BD), an interference-free end-to-end transmission architecture was proposed with destinations allowed to have multiple antennas. For the single destination scenario, there have been numerous previous works, e.g.…”

“…In this paper, we take the same approach as in [1] except that destinations are equipped with a single antenna, which is a more practical assumption. The interference-free scheme [1] in the case of single antenna destinations then reduces to a combination of SVD and zero-forcing (ZF) beamforming.…”

“…The interference-free scheme [1] in the case of single antenna destinations then reduces to a combination of SVD and zero-forcing (ZF) beamforming. With this setup, we devise a matching scheme that assigns subchannels at the first hop to power costs for the second hop with joint consideration of relay power allocation.…”