Beyond Turbo: An Integrated ADMM Receiver for URLLC MIMO Systems

The emergence of ultra-reliable and low-latency communication (URLLC) poses challenges on the receiver design. Classical turbo receivers, which exhibit excellent performance under long data packet transmissions, can suffer from non-negligible error propagation in the context of URLLC due to the use of short error correction codes. To address this issue, we advocate a novel joint detection and decoding (JDD) receiver for URLLC multi-input multi-output (MIMO) systems with short low-density parity-check (LDPC) codes. Specifically, we first establish a maximum likelihood (ML) based JDD problem formulation by incorporating the bit-to-symbol mapping and the LDPC code constraints, which circumvents the error propagation issue in turbo receivers. In order to solve this difficult large-scale non-convex problem, we develop a low-complexity alternating direction method of multipliers (ADMM) algorithm to directly acquire the ultimate decoding results. Simulation results validate the performance advantage of the proposed JDD receiver over the turbo receivers in the URLLC scenario.