Abstract
This paper focuses on the low-complexity multiuser detection of coded low-density signature (LDS) systems where the numbers of resources and users are both large. Typically, the detection complexity using the conventional message passing algorithm grows exponentially with the number of users occupied at each resource, making it unaffordable for large-scale LDS systems. To address this problem, we propose to apply orthogonal approximate message passing (OAMP) to detect LDS symbols with polynomial complexity. The numerical results demonstrate the superiority of the proposed method in terms of the error performance over the traditional turbo receiver.