In this paper we propose LoRaSyNc (LoRa receiver with SyNchronization and Cancellation), a second generation LoRa receiver that implements Successive Interference Cancellation (SIC) and time synchronization to improve the performance of LoRa gateways. Indeed, the chirp spread spectrum modulation employed in LoRa experiences very high capture probability, and cancelling the strongest signal in case of collisions can significantly improve the cell capacity. An important feature of LoRaSyNc is the ability to track the frequency and clock drifts between the transmitter and receiver, during the whole demodulation of the interfered frame. Due to the use of low-cost oscillators on end-devices, a signal cancellation scheme cannot result accurate without such a tracking, especially at the lower data rates. We validate the performance of LoRaSyNc in presence of collisions by implementing a receiver prototype on software-defined-radios, and perform several experiments in different realistic scenarios, by also comparing our receiver with commercial gateways. Finally, we simulate a cell deployment with one or more gateways, showing that the proposed scheme improves performance by almost 50% compared to a traditional receiver.

中文翻译：

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LoRa网关的干扰消除及其对网络容量的影响


在本文中，我们提出了 LoRaSyNc（具有同步和消除功能的 LoRa 接收器），这是第二代 LoRa 接收器，它实现了连续干扰消除 (SIC) 和时间同步，以提高 LoRa 网关的性能。事实上，LoRa 中采用的线性调频扩频调制具有非常高的捕获概率，并且在发生冲突时消除最强信号可以显着提高小区容量。 LoRaSyNc 的一个重要功能是能够在受干扰帧的整个解调过程中跟踪发送器和接收器之间的频率和时钟漂移。由于终端设备上使用了低成本振荡器，如果没有这样的跟踪，信号消除方案就无法获得准确的结果，尤其是在较低的数据速率下。我们通过在软件定义的无线电上实现接收器原型来验证 LoRaSyNc 在存在冲突的情况下的性能，并通过将我们的接收器与商业网关进行比较，在不同的实际场景中进行多项实验。最后，我们模拟了具有一个或多个网关的小区部署，结果表明，与传统接收器相比，所提出的方案将性能提高了近 50%。