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arXiv 2502.06239eess.SPcs.ITmath.IT
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预均衡辅助的大规模MIMO系统中免授权海量接入

Pre-Equalization Aided Grant-Free Massive Access in Massive MIMO System

Yueqing Wang, Yikun Mei, Zhen Gao, Ziwei Wan, Boyu Ning, De Mi, Sami Muhaidat

AI总结:

针对mMIMO系统免授权大规模NOMA方案导频开销大、接入时延高的问题,提出预均衡辅助的免授权海量接入方案,设计含粗检测、数据辅助信道估计和精检测的迭代算法,相同时延下性能优于现有方案。

摘要:

大规模多输入多输出(mMIMO)的空间分集和复用优势可显著提升机器类通信中大规模非正交多址(NOMA)的容量。然而,当前mMIMO系统的免授权大规模NOMA方案需准确估计随机接入信道以执行活动检测及后续相干数据解调,存在导频开销过大和接入时延高的问题。为此,我们提出一种mMIMO系统中预均衡辅助的免授权海量接入方案,并设计了迭代检测机制。具体而言,基站(BS)首先激活其一根天线(即信标天线)广播信标信号,便于用户设备(UEs)进行下行信道估计,并基于信标天线关联信道对上行随机接入信号进行预均衡。在上行传输阶段,BS利用所提迭代检测算法检测UEs的活动状态与数据,该算法包含三个模块:粗数据检测(DD)、数据辅助信道估计(CE)和精数据检测。所提算法首先基于信标天线接收的信号执行联合活动与数据检测,随后通过迭代运行数据辅助CE模块和精DD模块(利用所有BS天线接收的信号)进一步优化数据检测结果。仿真结果表明,在相同接入时延下,所提方案性能优于现有基于mMIMO的免授权大规模NOMA方案。仿真代码已提供,可复现本文结果:https://github.com/owenwang517/tvt-2025。

英文摘要:

The spatial diversity and multiplexing advantages of massive multi-input-multi-output (mMIMO) can significantly improve the capacity of massive non-orthogonal multiple access (NOMA) in machine type communications. However, state-of-the-art grant-free massive NOMA schemes for mMIMO systems require accurate estimation of random access channels to perform activity detection and the following coherent data demodulation, which suffers from excessive pilot overhead and access latency. To address this, we propose a pre-equalization aided grant-free massive access scheme for mMIMO systems, where an iterative detection scheme is conceived. Specifically, the base station (BS) firstly activates one of its antennas (i.e., beacon antenna) to broadcast a beacon signal, which facilitates the user equipment (UEs) to perform downlink channel estimation and pre-equalize the uplink random access signal with respect to the channels associated with the beacon antenna. During the uplink transmission stage, the BS detects UEs' activity and data by using the proposed iterative detection algorithm, which consists of three modules: coarse data detection (DD), data-aided channel estimation (CE), and fine DD. In the proposed algorithm, the joint activity and DD is firstly performed based on the signals received by the beacon antenna. Subsequently, the DD is further refined by iteratively performing data-aided CE module and fine DD module using signals received by all BS antennas. Our simulation results demonstrate that the proposed scheme outperforms state-of-the-art mMIMO-based grant-free massive NOMA schemes with the same access latency. Simulation codes are provided to reproduce the results in this article: https://github.com/owenwang517/tvt-2025.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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