Long Range (LoRa) has become one of the most promising physical layer technologies for the Internet of Things (IoT) ecosystem. Although it manifests low-power consumption and long-distance communication, LoRa encounters a large number of collisions in the IoT environment, which severely affects the system’s throughput and delay performance. In this paper, a code division carrier sense multiple access (CD/CSMA) protocol that resolves the traditional channel collision problem and implements multi-channel transmission is proposed for the LoRa medium access control (MAC) layer. To reduce data transmission delay and maximize the throughput of the system, the adaptive p-persistent CSMA protocol divides the channel load into four states and dynamically adjusts the data transmission probability. Then, to reduce channel collisions significantly, the code division multiple access (CDMA) protocol is performed on different channel states. Moreover, the combination of the proposed adaptive p-persistent CSMA protocol and the CDMA successfully reduces the number of data retransmissions and makes LoRa more stable. The simulation results demonstrate that the proposed adaptive p-persistent CD/CSMA protocol can achieve near-optimal and occasionally even better performance than some conventional MAC protocols, especially in a heavy load channel.

中文翻译：

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高性能基于长距离的媒体访问控制层协议

远程（LoRa）已成为物联网（IoT）生态系统最有希望的物理层技术之一。尽管LoRa表现出低功耗和长距离通信，但它在IoT环境中遇到了大量冲突，这严重影响了系统的吞吐量和延迟性能。本文针对LoRa介质访问控制（MAC）层，提出了一种码分载波侦听多路访问（CD / CSMA）协议，该协议解决了传统的信道冲突问题并实现了多信道传输。为了减少数据传输延迟并最大程度地提高系统的吞吐量，自适应p持久CSMA协议将信道负载分为四个状态并动态调整数据传输概率。然后，为了显着减少通道冲突，码分多址（CDMA）协议是在不同的信道状态下执行的。此外，所提出的自适应p持久CSMA协议和CDMA的组合成功地减少了数据重传的次数，并使LoRa更加稳定。仿真结果表明，所提出的自适应p持久CD / CSMA协议可以实现比某些常规MAC协议近乎最优的性能，有时甚至更好的性能，尤其是在重载信道中。