On the delay of finite buffered multi-hop relay wireless internet of things

Abstract

The evolution of Internet of Things (IoT) as a new application in wireless networks mandates the utilization of wireless cooperative relaying to overcome the energy limitations of IoT devices. Multi-hop relaying is a communication scheme, where packets are forwarded from source to destination through intermediate relay nodes. All these relay nodes are assumed to have buffers for temporarily storing their received packets. During each time-slot, one node can be selected among all nodes to transmit and forward a single packet to the consequent relay node towards the final destination. Based on the nature of the data and its sensitivity to the delay, different schemes can be used to control the movement of packets in the multi-hop networks. This paper presents a framework for the delay analysis of buffered multi-hop networks based on a recently proposed packet-forwarding scheme that uses the best hop for transmission. Based on the channel, the best hop, having the highest signal-to-noise ratio (SNR), is selected. This hop selection procedure produces selection diversity, which minimizes the error and outage probability. The network delay is studied analytically, based on a finite-state Markov chain model. Also, we derive analytical closed form expressions for the average queue length for each relay buffer in the network and the end-to-end network delay. Finally, we compare the delay and outage of the best hop scheme with the conventional multi-hop transmission scheme. The results show how the number of intermediate relays and the buffer size of each one can affect the network delay. - 2019 IEEE.