Eigen-Based Transceivers for the MIMO Broadcast Channel With Semi-Orthogonal User Selection

Abstract

This paper studies the sum rate performance of two low complexity eigenmode-based transmission techniques for the MIMO broadcast channel, employing greedy semi-orthogonal user selection (SUS).The first approach, termed ZFDPC-SUS, is based on zero-forcing dirty paper coding; the second approach, termed ZFBF-SUS, is based on zero-forcing beamforming. We first employ new analytical methods to prove that as the number of users K grows large, the ZFDPC-SUS approach can achieve the optimal sum rate scaling of the MIMO broadcast channel. We also prove that the average sum rates of both techniques converge to the average sum capacity of the MIMO broadcast channel for large K. In addition to the asymptotic analysis, we investigate the sum rates achieved by ZFDPC-SUS and ZFBF-SUS for finite K, and show that ZFDPC-SUS has significant performance advantages. Our results also provide key insights into the benefit of multiple receive antennas, and the effect of the SUS algorithm. In particular, we show that whilst multiple receive antennas only improves the asymptotic sum rate scaling via the second-order behavior of the multi-user diversity gain; for finite K, the benefit can be very significant. We also show the interesting result that the semi-orthogonality constraint imposed by SUS, whilst facilitating a very low complexity user selection procedure, asymptotically does not reduce the multi-user diversity gain in either first (log K) or second-order (log log K) terms.

Recursive stream selection for CF MU-MIMO BC precoder design

“…Comparing the algorithms with each other, these curves confirm the previously stated results. Using the same precoding technique, the proposed selection algorithm outperforms the successive selection algorithm presented in [13]. For all the previously presented results, the step 2 of Algorithm 1 has been executed by selecting all streams in the set.…”

“…Nevertheless, DPC precoding is difficult to implement. Some suboptimal linear beamforming (BF) algorithms exist and can be divided into two main families: the iterative [4]- [8] and the closed form solutions [9]- [13]. These solutions can also be differentiated according to the EURECOMs research is partially supported by its industrial members: OR-ANGE, BMW Group, Swisscom, Cisco, SFR, ST Ericsson, Thales, Symantec, SAP, Monaco Telecom, and also by the EU FP7 projects CROWN, SACRA and WHERE2.…”

“…Such precoders have been proposed and widely studied in [6], [7], [9]- [12]. Some multi-stream precoding solutions have nevertheless been proposed such as in [13], [14]. To the best of our knowledge, the best linear CF precoder present in the literature is the so called ZFDPC-SUS (ZF DPC with successive user selection) that has been proposed in [13], [15].…”

“…Some multi-stream precoding solutions have nevertheless been proposed such as in [13], [14]. To the best of our knowledge, the best linear CF precoder present in the literature is the so called ZFDPC-SUS (ZF DPC with successive user selection) that has been proposed in [13], [15]. This precoding technique is based on the selection of semi-orthogonal users based on the SVD of their respective channels.…”

Physical Layer Security for Multiuser MIMO Communications

“…Although suboptimal, linear precoding schemes are of particular interest because of their low-complexity implementations and because they can control the amount of crosstalk between the users to maintain a high sum-rate in the broadcast channel [20][21][22][23][24][25][26][27]. In the MISO BCC, linear precoding can be employed to control the amount of interference and information leakage to the unintended receivers introduced by the transmission of each confidential message [17][18][19].…”