This paper considers massive Internet of Things systems, especially for LoW Power Wide Area Networks, that aim at connecting billions of low-cost devices with multi-year battery life requirements. Current systems for massive Internet of Things exhibit severe problems when trying to pursue the target of serving a very large number of users. In this paper, a novel asynchronous spread spectrum modulation, called Golden Modulation, is introduced. This modulation provides a vast family of equivalent waveforms with very low cross-interference even in asynchronous conditions, hence enabling natural multiuser operation without the need for inter-user synchronization or for interference cancellation receivers. Thanks to minimal interference between waveforms, coupled with the absence of coordination requirements, this modulation can accommodate very high system capacity. The basic modulation principles, relying on spectrum spreading via direct Zadoff-Chu sequences modulation, are presented and the corresponding theoretical bit error rate performance in an additive white Gaussian noise channel is derived and compared by simulation with realistic Golden Modulation receiver performance. The demodulation of the Golden Modulation is also described, and its performance in the presence of uncoordinated multiple users is characterized.
翻译:本文考虑海量物联网系统,尤其是面向低功耗广域网的系统,旨在连接数以亿计的低成本设备,其电池寿命要求为数年。目前,海量物联网系统存在严重问题,尝试追求为大量用户提供服务的目标时,问题更加严重。本文介绍了一种新型的异步扩频调制,称为Golden Modulation。这种调制提供了大量等效波形,即使在异步条件下也具有极低的互干扰,因此无需互用户同步或干扰取消接收器即可自然地实现多用户操作。由于波形之间的互干扰极小且无需协调需求,因此该调制可以容纳非常高的系统容量。介绍了基本的调制原理,依赖于通过直接的Zadoff-Chu序列调制实现的频谱扩展,并导出了在加性白噪声信道中的理论误码率性能,并通过模拟与实际的Golden Modulation接收器性能进行比较。还描述了对Golden Modulation的解调,以及在未协调多用户的情况下其性能的特征。