Resource Management Of Relay Enhanced Cellular Networks

As novel and cost-effective network architecture, the relay enhanced cellular network is proposed and can be satisfied with the ubiquitous high data rate requirement of the next generation wireless systems. The relay enhanced cellular networks integrate the“multihop”capability into the conventional cellular systems by employing the relay nodes and dividing the directly connecting link between Base Stations (BSs) and User Terminals (UTs) into several hops. Thus, the communication distance is reduced and the link quality and channel capacity can be improved significantly.This dissertation investigates the frequency reuse based frequency planning problem; the link based adaptive resource allocation problem and the fair resource scheduling problem in relay enhanced cellular networks. It is a meaningful research work for achieving the higher data rate and ubiquitous coverage of the future mobile communication systems.Frequency planning is an economical and applicable approach to improve the performance of wireless networks. Effective frequency planning is the main method to increase the system capacity and coverage. This dissertation gives a deeper research on one frequency reuse based frequency planning scheme, has set up a theoretical analysis model and done some research on the interference, SIR (signal to interference ratio) of the uplinks and the transmit power of user terminals. Based on the analysis, one modified frequency reuse scheme is proposed for relay enhanced cellular networks. The simulation results show that the modified scheme has better performance. This dissertation gives the research on the adaptive resource allocation algorithms of the relay enhanced cellular network, a more complex multiuser OFDM system. By analyzing the system model and the radio frequency characteristic of relay nodes, a two-slots transmit pattern is proposed and one optimization model of the resource allocation problem is set up. By simplifying the model, one‘two step’iterative allocation algorithm is proposed. Simulation results show that the proposed algorithm can achieve high system capacity by low computing complexity.Additionally, this dissertation gives a meaningful exploration on fair resource scheduling of relay enhanced cellular networks. By introducing the traditional Round Robin algorithm as a benchmark, the greedy polling and partial proportional fair algorithm is proposed. The numerical results show that greedy polling algorithm has small jitter and can gain steady throughput. The partial proportional fair algorithm can achieve more capacity gain and is very suited for packet based non-real services.