In this correspondence, we present a novel soft-output-sparse-aware (SOSA) detector for an uplink multiuser multiple-input-multiple-output system. The proposed detector consists of two steps: First, a transmit vector is detected using a low-complexity detector; second, an improved soft-output is generated by exploiting the sparsity of a residual error vector (i.e., the difference between the transmit vector and the detected one). In contrast, the previous sparse-aware (SA) detectors used the sparsity to refine the hard-decision output of the underlying detector. Therefore, the SOSA detector can significantly outperforms the (hard-output) SA detectors for the coded systems since the former only can be well-incorporated into state-of-the-art soft channel decoders. Via simulation results, we demonstrate that the SOSA detector attains a nontrivial coded gain over the (soft-output) underlying detector with a similar complexity. Furthermore, the performance gap grows as signal-to-noise ratio and a system size grow.
Manuscript received October 26, 2017; revised February 28, 2018 and April 27, 2018; accepted June 8, 2018. Date of publication June 11, 2018; date of current version September 17, 2018. This work was supported in part by the Electronics and Telecommunications Research Institute grant funded by the Korean Government (18ZF1100, Wireless Transmission Technology in Multipoint to Multipoint Communications) and in part by the frame of international cooperation program managed by the National Research Foundation of Korea under Grant 2017K2A9A2A06016102. The review of this paper was coordinated by Dr. K. Temma. (Corresponding author: Song-Nam Hong.) The authors are with the Department of Electrical Engineering, Ajou University, Suwon 16499, South Korea (e-mail:, net2616@ajou.ac.kr; sunnyran @ajou.ac.kr; oskn@ajou.ac.kr; snhong@ajou.ac.kr).
