On Precoding for Constant K-User MIMO Gaussian Interference Channel With Finite Constellation Inputs

Ganesan, Abhinav and Rajan, Sundar B (2014) On Precoding for Constant K-User MIMO Gaussian Interference Channel With Finite Constellation Inputs. In: IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, 13 (8). pp. 4104-4118.

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Abstract

This paper considers linear precoding for the constant channel-coefficient K-user MIMO Gaussian interference channel (MIMO GIC) where each transmitter-i (Tx-i) requires the sending of d(i) independent complex symbols per channel use that take values from fixed finite constellations with uniform distribution to receiver-i (Rx-i) for i = 1, 2, ..., K. We define the maximum rate achieved by Tx-i using any linear precoder as the signal-to-noise ratio (SNR) tends to infinity when the interference channel coefficients are zero to be the constellation constrained saturation capacity (CCSC) for Tx-i. We derive a high-SNR approximation for the rate achieved by Tx-i when interference is treated as noise and this rate is given by the mutual information between Tx-i and Rx-i, denoted as I(X) under bar (i); (Y) under bar (i)]. A set of necessary and sufficient conditions on the precoders under which I(X) under bar (i); (Y) under bar (i)] tends to CCSC for Tx-i is derived. Interestingly, the precoders designed for interference alignment (IA) satisfy these necessary and sufficient conditions. Furthermore, we propose gradient-ascentbased algorithms to optimize the sum rate achieved by precoding with finite constellation inputs and treating interference as noise. A simulation study using the proposed algorithms for a three-user MIMO GIC with two antennas at each node with d(i) = 1 for all i and with BPSK and QPSK inputs shows more than 0.1-b/s/Hz gain in the ergodic sum rate over that yielded by precoders obtained from some known IA algorithms at moderate SNRs.

Item Type:	Journal Article
Publication:	IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
Publisher:	IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Additional Information:	Copy right for this article belongs to the IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA.
Keywords:	Gaussian interference channel; treating interference as noise; precoding; finite constellation; interference alignment
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	08 Nov 2014 05:13
Last Modified:	08 Nov 2014 05:13
URI:	http://eprints.iisc.ac.in/id/eprint/50175

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