标题： 基于确定性非正交签名的大量无许可访问联合活动和数据检测 显示英文标题

标题： Joint Activity and Data Detection for Massive Grant-Free Access Using Deterministic Non-Orthogonal Signatures

摘要： 无许可接入是实现大规模机器类型通信(mMTC)中无线设备低延迟和低信令开销的关键使能技术。 对于大规模无许可接入，用户特定的签名被唯一分配给mMTC设备。 在本文中，我们首先推导出通过最大似然(ML)估计在大规模无许可接入中成功识别活动设备的充分条件。 该条件由包含所有设备签名的签名序列矩阵的相干性表示。 然后，我们以确定性方式提出了一种非正交签名序列的设计框架。 设计原理依赖于具有低相关的单模遮罩序列，这些序列被用作离散傅里叶变换(DFT)矩阵列的遮罩序列。 例如构造中，我们使用了由有限域上的字符表示的四个多相遮罩序列。 利用代数技术，我们证明了所提出的非正交序列的签名序列矩阵具有理论上有限的低相干性。 仿真结果表明，确定性的非正交签名通过基于ML和近似消息传递(AMP)的算法，在mMTC中的大规模无许可接入中实现了卓越的联合活动和数据检测性能。 显示英文摘要

摘要： Grant-free access is a key enabler for connecting wireless devices with low latency and low signaling overhead in massive machine-type communications (mMTC). For massive grant-free access, user-specific signatures are uniquely assigned to mMTC devices. In this paper, we first derive a sufficient condition for the successful identification of active devices through maximum likelihood (ML) estimation in massive grant-free access. The condition is represented by the coherence of a signature sequence matrix containing the signatures of all devices. Then, we present a design framework of non-orthogonal signature sequences in a deterministic fashion. The design principle relies on unimodular masking sequences with low correlation, which are applied as masking sequences to the columns of the discrete Fourier transform (DFT) matrix. For example constructions, we use four polyphase masking sequences represented by characters over finite fields. Leveraging algebraic techniques, we show that the signature sequence matrix of proposed non-orthogonal sequences has theoretically bounded low coherence. Simulation results demonstrate that the deterministic non-orthogonal signatures achieve the excellent performance of joint activity and data detection by ML- and approximate message passing (AMP)-based algorithms for massive grant-free access in mMTC.