Analyses of QoS-based relay deployment in 4G LTE-A wireless mobile relay networks

In 4G cellular networks: LTE/LTE-Advanced and the mobile WiMax network, some key impact factors degrade signal transmission quality and reduce wireless service coverage significantly. The specifications of LTE-Advanced and IEEE 802.16j thus propose a relay-based scheme, namely Mobile Multihop Relay (MMR) networks, to cooperate with the existing cellular network and to guarantee QoS for requests while not obviously increasing the Relay Station (RS) deployment cost. To efficiently deploy different types of RSs becomes a critical issue. Thus, this paper first analyzes the impact factors: transmission quality, deployment price, service coverage and RS overlap index, and then models the cost-effective issue of the RS deployment as an optimization problem. The paper proposes an Adaptive Cost-based RS Deployment (ACRD) approach to form a cost function in terms of all impact factors, and then solves the optimization problem by determining the RS deployment with the least network cost as the solution. Numerical results demonstrate that ACRD outperforms the compared approaches in network cost, transmission quality, RS deployment price, service coverage, and RS overlap index. ACRD deploys more RSs on the areas with high-density populations and thus increases transmission quality and guarantees the quality of service (QoS).