Clustering-Based Layering Approach for Uplink Multi-Hop Communication in LoRa Networks

Abstract

LoRa is the most popular low-power wide-area networking (LPWAN) technology, and typically it uses LoRaWAN as the MAC layer. Usually, LoRaWAN forms a single-hop network. LoRa supports customization of transmission parameters, such as, bandwidth, spreading factor, and coding rate. Hence, a single-hop LoRaWAN network’s coverage can be increased at the expense of higher energy consumption and lower data rate. However, there are a few issues: ( ${i}$ ) there is an upper bound on a single-hop network’s coverage, ( ii ) high throughput and large coverage can not be achieved simultaneously, and ( iii ) most importantly high energy consumption is generally not an option in IoT use cases. Here, a multi-hop uplink communication scheme is presented that exploits LoRa’s ability to customize its transmission parameters and combine it with a novel routing protocol to eliminate the mentioned shortcomings. In simulation-based studies the proposed protocol uses LoRa’s fastest data rate setting, however its coverage is lower than the LoRa’s PHY layer setting recommended in LoRaWAN specification. Hence, a network’s coverage is extended through multi-hop communication. Results have shown that the proposed uplink multi-hop communication scheme outperforms LoRaWAN and a state-of-the-art routing protocol for low-power wireless networks. The proposed protocol demonstrated nearly 20 times higher packet delivery ratio, and 60% lower energy consumption.