Queuing Analysis of Two-Hop Relay Technology in LTE/LTE-A Networks With Unsaturated and Asymmetric Traffic

Relay technology is one of the key technologies for long-term evolution advanced (LTE-A) project. The introduction of relay will not only bring a wider coverage and higher capacity to the system but also lower the cost of network building. Multihop wireless relay technology plays an important role in next-generation mobile and wireless communication systems. Nowadays, we are witnessing the formation of a new technological marvel: Internet of Things (IoT). This formation is able to combine in a particular operational entity, all the bits and pieces of the world around us. In this paper, we perform queuing modeling of a two-hop wireless relay network and carry out performance analysis of end-to-end packet delay. In the two-hop wireless relay network, two groups of wireless nodes (WNs) and a single relay node (RN) are considered. A Poisson packet arrival process and IEEE 802.11 distributed coordination function are assumed in the network for the network traffic model and for regulating the nodes' access to the shared channel, respectively. We model a node as a single-server queuing system, whose service time of a packet is unknown and dependent on the probabilistic parameters of IEEE 802.11 DCF medium access control (MAC). A system of equations is then obtained for numerically computing the probabilistic parameters of IEEE 802.11 DCF MAC through discretization of the continuous-time network operations, based on which we construct semi-Markov processes and derive an analytic result for the expectation of the end-to-end packet delay. As a key performance indicator in evaluation of wireless networks, the packet delay result helps measure the efficiency of IEEE 802.11 MAC in two-hop wireless relay networks.