A New Planning-Based Collision-Prevention Mechanism in Long-Range IoT Networks

Wireless communication is prone to collisions, resulting from multiple devices transmitting at the same time. It implies subsequent retransmissions, which increase energy consumption of communicating devices and reduce throughput of the network. This is especially critical in Internet of Things (IoT) networks, in which the number of connected devices grows rapidly and the available energy of IoT end devices is rather limited (e.g., energy harvesting and battery powered). The number of retransmissions must be reduced in order the networks to be sustainable. However, in long-range wireless IoT networks, the most effective collision-resolution techniques using a transmission-channel listening to detect collisions cannot be reliably used due to various problems, such as a hidden-node problem or environment interference. In this article, a new solution of this problem is proposed, which consists of a new communication-planning mechanism for low-speed long-range IoT networks with a huge number of communicating energy-constrained devices. The access points (APs) (or IoT gateways) are used to plan the periodically repeated communication into a transmission schedule, allowing only a single IoT device to communicate at a time. This approach results in reduction of collisions, which leads to the increased network throughput, smaller delays, and lower power requirements of energy-constrained devices. The experiments indicate that the proposed approach provides better communication efficiency than the LoRaWAN and Sigfox collision-resolution techniques, when more than 15, respectively 125, end devices communicate with a single AP.