LTE-Railway User Priority-Based Cooperative Resource Allocation Schemes for Coexisting Public Safety and Railway Networks

This paper addresses the issues of resource allocation and co-channel interference management for coexistence of, and cooperation between, two long term evolution (LTE) networks. In the Republic of Korea, the LTE-based public safety (PS-LTE) network is being built for the 700-MHz frequency band. However, the same band is also allocated to the LTE-based high-speed railway (LTE-R) network, so immense interest and useful researches into co-channel interference management schemes are immediately needed. In this paper, we focus on the downlink system of coexisting PS-LTE and LTE-R networks by considering LTE-R radio access network (RAN) sharing and non-RAN sharing by PS-LTE users equipment (UEs) to analyze the co-channel interference. We also utilize cooperative communications schemes, such as coordinated multipoint (CoMP) and inter-cell interference coordination (ICIC) in order to resolve the problem of co-channel interference. We categorize the coexistence of PS-LTE and LTE-R networks into five different scenarios, and evaluate the performance of each scenario based on various performance indexes, such as UE average throughput, UE received interference, and UE outage probability. Moreover, users can achieve high throughput as well as obtain a better channel condition by using RAN sharing. In addition, we always provide the higher priority to railway user while allocating the resources for coexisting public safety and railway networks using LTE-R RAN sharing by PS-LTE UEs, because train control signal needs more reliable communication as well as low latency in order to fulfil its mission-critical service (MCS) demands. By employing coordinated scheduling (CS) CoMP, the highest throughput performance can be attained with RAN sharing. Furthermore, the dynamic ICIC enhances cell-edge UE performance and reduces UE received interference, as well as the outage probability, by using the partial reuse band and bonus band allocation.