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arXiv 2209.02548eess.SP
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毫米波无蜂窝大规模MIMO网络中的软切换流程

Soft Handover Procedures in mmWave Cell-Free Massive MIMO Networks

Mahmoud Zaher, Emil Björnson, Marina Petrova

AI总结:

本文针对毫米波无蜂窝大规模MIMO网络中的UE移动性问题,提出分布式联合导频分配与簇形成算法,在保证频谱效率的同时大幅降低计算复杂度和导频变更次数。

摘要:

本文研究一个毫米波无蜂窝大规模MIMO(多输入多输出)网络,该网络由大量地理上分布的接入点(AP)组成,通过相干联合传输同时服务多个用户设备(UE)。我们在下行链路(DL)中考虑UE移动性,并考虑不完善的信道状态信息(CSI)和导频训练。为了将传统切换概念扩展到无蜂窝网络中具有挑战性的AP-UE关联策略,在考虑UE移动性的动态环境中提出了用于联合导频分配和簇形成的分布式算法。这些算法为每个UE的初始接入以及服务AP和所分配导频序列的更新提供了系统化流程。主要目标是在限制计算复杂度的同时,限制必要的AP和导频变更次数。我们以最大比和正则化迫零预编码,在频谱效率(SE)方面评估了性能。结果表明,与现有最优方法相比,我们提出的分布式算法能够有效识别必要的AP-UE关联优化,计算时间降低了数个数量级。与超密集网络(UDN)相比,它还显著降低了平均导频变更次数。此外,我们开发了一种改进的导频分配流程,在高负载场景下有助于实现大规模网络接入。

英文摘要:

This paper considers a mmWave cell-free massive MIMO (multiple-input multiple-output) network composed of a large number of geographically distributed access points (APs) simultaneously serving multiple user equipments (UEs) via coherent joint transmission. We address UE mobility in the downlink (DL) with imperfect channel state information (CSI) and pilot training. Aiming at extending traditional handover concepts to the challenging AP-UE association strategies of cell-free networks, distributed algorithms for joint pilot assignment and cluster formation are proposed in a dynamic environment considering UE mobility. The algorithms provide a systematic procedure for initial access and update of the serving APs and assigned pilot sequence to each UE. The principal goal is to limit the necessary number of AP and pilot changes, while limiting computational complexity. We evaluate the performance, in terms of spectral efficiency (SE), with maximum ratio and regularized zero-forcing precoding. Results show that our proposed distributed algorithms effectively identify the essential AP-UE association refinements with orders-of-magnitude lower computational time compared to the state-of-the-art. It also provides a significantly lower average number of pilot changes compared to an ultra-dense network (UDN). Moreover, we develop an improved pilot assignment procedure that facilitates massive access to the network in highly loaded scenarios.

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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