Monitoring Resource Activity-Based Retransmission Control Process in Multi-Hop LoRaWAN

초록

To achieve long-range communication, a single-hop long-range wide area network (LoRaWAN) must sacrifice throughput. In contrast, multi-hop LoRaWAN can extend the communication range while maintaining high throughput by introducing relay nodes between a transmitter and a receiver. However, several challenges arise in multi-hop LoRaWAN. First, the hidden-node problem can lead to packet collisions because relay nodes operate autonomously and may not detect other nodes’ transmissions. Second, the acknowledgment (ACK)-based retransmission control process (ACK-RCP) reduces the throughput due to the duty cycle constraint imposed on unlicensed bands. To address these challenges, this paper proposes a monitoring resource activity-based retransmission control process (MRA-RCP) that determines whether retransmission is necessary by overhearing signal transmission in the next hop. Thus, it does not require explicit feedback from the receiving node. The simulation results show that the proposed MRA-RCP can increase the number of successfully delivered packets to 187 % of that of the system with the conventional ACK-RCP. Furthermore, experimental evaluations with commercially available LoRaWAN nodes show that the proposed MRA-RCP achieves 192 % of the packets successfully delivered, compared to the conventional ACK-RCP in a real LoRaWAN environment.

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