Low-Complexity EP Receiver Based on Location-Aware and Reliability-Aware Strategy

Abstract

The expectation propagation (EP) algorithm has received significant attention recently due to its good performance and manageable computational complexity for large-scale inference problems, such as detection for massive multiple-input multiple-output (MIMO) systems. Its computational complexity depends mainly on how messages are represented for computation and passing. In this letter, we propose a low-complexity EP algorithm based on location-aware and reliability-aware strategy, shortened as LR-EP, to efficiently implement the message computation and passing. At each iteration, only the most probable symbol candidates are selected to perform message computation based on a low-complexity quadrant detection and predetermined lookup table. In the iterative process, reliable variable nodes with sufficiently high posterior probabilities are kept intact, thus reducing the less efficient message passing. Numerical results illustrate that the proposed LR-EP receiver reduces computational complexity significantly compared to the conventional EP receiver with negligible performance degradation.