A Hybrid Relay Strategy for Low-latency Communication in Multi-Hop Wireless Networks

Multi-hop wireless networks play a vital role in monitoring of oil pipelines and high-speed railways. The conventional analog amplify-and-forward (AF) relay strategy has low process latency but it can make unreliable connections due to the amplified noise with the increasing hops. In addition, decode-and-forward (DF) method is accurate but it introduces longer processing time thus the end-to-end delay is not satisfied. To this end, we propose a new hybrid relay strategy to provide low end-to-end latency communication. The source node, relays and destination nodes are classified into several clusters. In one cluster, the cluster head works in DF mode while the cluster members works in AF mode. More importantly, we first establish an effective analytical model of the proposed strategy and then design a low overhead medium access control (MAC) protocol for each relay to determine their relay mode. Finally, we compare the signal to interference plus noise ratio (SINR) and end-to-end transmission delay with conventional half-duplex DF scheme. Simulation result shows that compared to it, the proposed transmission scheme can extend the coverage range and provide low latency communication.