A vision of a digital and connected world is now a global strategy for 5G Internet of Things (IoT), targeting for high-speed communication services with more capacity, lower latency, increased reliability, and availability. In this article, we assess the added value of backscatter communication in 5G IoT technology, by studying spatial modulation (SM)-based techniques, applied over a traditional multiple antenna backscatter communication system. Particularly, with backscatter, we fulfill the need for wireless self-powered devices, as one of the main characteristics of 5G IoT. Furthermore, with the use of multiple antennas, we apply sophisticated techniques that enhance the overall efficiency of the backscatter communication system. Initially, we study generalized SM (GSM) and its special case of SM, exploiting the antenna index as an additional source of information. With this technique, enhanced performance in terms of symbol error rate (SER) and spectral efficiency, is provided. In addition, we expand GSM in the time domain, by applying the Alamouti coding scheme (GSMA) in two out of the multiple available antennas. In this way, we further enhance the performance and succeed transmit diversity. Finally, analytical expressions regarding the pairwise error probability are derived and presented, while a diversity analysis is carried out for the proposed techniques. The simulation results along with theoretical bounds are provided, validating the enhanced performance of our study.

中文翻译：

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用于反向散射通信系统的基于空间调制的技术


数字互联世界的愿景现已成为 5G 物联网 (IoT) 的全球战略，目标是提供容量更大、延迟更低、可靠性和可用性更高的高速通信服务。在本文中，我们通过研究应用于传统多天线反向散射通信系统的基于空间调制 (SM) 的技术，评估了 5G IoT 技术中反向散射通信的附加值。特别是，通过反向散射，我们满足了无线自供电设备的需求，这是 5G 物联网的主要特征之一。此外，通过使用多个天线，我们应用了复杂的技术来提高反向散射通信系统的整体效率。最初，我们研究广义 SM (GSM) 及其 SM 的特殊情况，利用天线索引作为额外的信息源。利用该技术，可以增强符号错误率 (SER) 和频谱效率方面的性能。此外，我们通过在多个可用天线中的两个中应用 Alamouti 编码方案 (GSMA)，在时域中扩展 GSM。这样，我们进一步提高了性能并成功实现了发射分集。最后，推导并提出了关于成对误差概率的解析表达式，同时对所提出的技术进行了多样性分析。提供了模拟结果以及理论界限，验证了我们研究的增强性能。