Grant-free non-coherent index-modulation (NC-IM) has been recently considered as an efficient massive access scheme for enabling cost- and energy-limited Internet-of-Things (IoT) devices that transmit small data packets. This paper investigates the grant-free NC-IM scheme combined with orthogonal frequency division multiplexing for applicant to unmanned aerial vehicle (UAV)-based massive IoT access. Specifically, each device is assigned a unique non-orthogonal signature sequence codebook. Each active device transmits one of its signature sequences in the given time-frequency resources, by modulating the information in the index of the transmitted signature sequence. For small-scale multiple-input multiple-output (MIMO) deployed at the UAV-based aerial base station (BS), by jointly exploiting the space-time-frequency domain device activity, we propose a computationally efficient space-time-frequency joint activity and blind information detection (JABID) algorithm with significantly improved detection performance. Furthermore, for large-scale MIMO deployed at the aerial BS, by leveraging the sparsity of the virtual angular-domain channels, we propose an angular-domain based JABID algorithm for improving the system performance with reduced access latency. In addition, for the case of high mobility IoT devices and/or UAVs, we introduce a time-frequency spread transmission (TFST) strategy for the proposed JABID algorithms to combat doubly-selective fading channels. Finally, extensive simulation results are illustrated to verify the superiority of the proposed algorithms and the TFST strategy over known state-of-the-art algorithms.

中文翻译：

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无人机辅助大规模物联网接入的联合活动和盲信息检测

免授权非相干指数调制 (NC-IM) 最近被认为是一种有效的大规模接入方案，用于实现传输小数据包的成本和能量受限的物联网 (IoT) 设备。本文研究了结合正交频分复用的无授权 NC-IM 方案，适用于基于无人机 (UAV) 的大规模物联网接入。具体来说，每个设备都被分配了一个唯一的非正交签名序列码本。每个有源设备通过调制传输的签名序列的索引中的信息，在给定的时频资源中传输其签名序列之一。对于部署在基于无人机的空中基站（BS）的小规模多输入多输出（MIMO），通过联合利用时空域设备活动，我们提出了一种计算效率高的空时频联合活动和盲信息检测（JABID）算法，具有显着提高的检测性能。此外，对于部署在空中基站的大规模 MIMO，通过利用虚拟角域信道的稀疏性，我们提出了一种基于角域的 JABID 算法，以提高系统性能并降低访问延迟。此外，对于高移动性物联网设备和/或无人机的情况，我们为所提出的 JABID 算法引入了时频扩展传输 (TFST) 策略，以对抗双选择性衰落信道。最后，说明了广泛的仿真结果，以验证所提出的算法和 TFST 策略相对于已知的最先进算法的优越性。