A novel low-complexity multiuser detection scheme is proposed for the asynchronous non-orthogonal multiple access (NOMA). Directly applying the conventional symbol-synchronous detection techniques for the asynchronous NOMA would result in high complexity. For low-complexity, we divide one frame with a large number of symbols into several small blocks. Furthermore, for real-time and low-delay processing under the scenario with a large number of users, each block is independently processed in a parallel way by an approximate message passing-based algorithm. Furthermore, a jointly detection technique is proposed to address the large detection error in the boundary of the blocks, which is induced by the non-interaction between neighbor blocks. Simulation results demonstrate that the proposed detection scheme can achieve near optimal performance with a much lower complexity.

中文翻译：

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异步 NOMA 的基于消息传递的近似检测

针对异步非正交多址(NOMA)，提出了一种新的低复杂度多用户检测方案。直接将传统的符号同步检测技术应用于异步 NOMA 会导致高复杂度。对于低复杂度，我们将具有大量符号的一帧分成几个小块。此外，为了在大量用户场景下的实时、低延迟处理，每个块通过基于近似消息传递的算法以并行方式独立处理。此外，提出了一种联合检测技术来解决由于相邻块之间的非交互而引起的块边界中的大检测误差。