Capacity-Region-Achieving Sparse Regression Codes for MIMO Multiple-Access Channels

TL;DR

This paper introduces a new coding framework using sparse regression codes and a specialized receiver for MIMO multiple-access channels, achieving capacity region and sum capacity.

Contribution

It develops a capacity-region-achieving coding scheme with a novel receiver and power allocation strategy for MIMO-MAC.

Findings

Achieves sum capacity with the proposed coding scheme.

Enables reliable parallel interference cancellation at the receiver.

Achieves the entire capacity region through time sharing.

Abstract

This paper proposes a coding framework for capacity-region-achieving sparse regression (SR) codes over MIMO multiple-access channels (MIMO-MAC), where a single SR code is used for each user at the transmitter. With random semi-unitary dictionary matrices applied for encoding, multiple-access OAMP (MA-OAMP) enables reliable parallel interference cancellation (PIC) at the receiver. Theoretically, an optimal coding principle with the MA-OAMP receiver, which achieves the sum capacity and, in combination with time sharing, achieves the entire capacity region, is established as the guiding principle for designing capacity-region-achieving codes. Accordingly, a coding scheme for capacity-region-achieving SR codes is proposed via proper power allocation over the position-modulated signals.