Research And System-level Simulation Verification Of Relaying Technologies For LTE-Advanced

3 GPP LTE-Advanced,based on LTE (Long Term Evolution),is a radio interface technology for ITU next generation mobile communication system (IMT-Advanced). In order to fulfill the requirement of high data rate wireless services in the future wireless communication system,LTE-Advanced systems need to provide better performance in terms of both cell average and cell edge throughput. Wireless Relay,as a lower-power and lower-cost network node compared to eNB,has been introduced in LTE-Advanced.It offers more flexible deployment options and provides an attractive means of augmenting network for coverage extension and throughput enhancement.Currently,the major telecom operators in the world,such as CMCC,Vodafone, NTT DoCoMo,are committed on designing and standardizing Relaying technology in LTE-Advanced.In addition, the mobile communication equipment makers,such as ZTE, Huawei,CATT,Qualcomm,are also actively promoting the development of Relaying technology.According to 3GPP TS36.814,at least "Type 1" relay nodes are part of LTE-Advanced,and fixed relays are the primary design considerations.At present,major domestic and foreign communication equipment makers,mobile network operators have been investing significant resources on various aspects of relay design,including Relay system evaluations,prototyping,and algorithm development,in order to grasp market shares in the 4G era.This thesis focuses on Relay performance evaluation and analysis through system level simulations.Based on system level simulations, further research on Relaying and the related 3GPP proposals are provided.The primary contributions are as follows:(1) Construction of system level simulator for Relay.The dynamic system simulation platform is developed according to the Relay simulation parameters provided in 36.814 and the related proposals in 3GPP Working Groups.The simulation platform consists of several modules,including serving cell association, cell layout,Relay/UE distribution,wireless channel modeling,link adaptation, scheduling,interference estimation,etc.In this paper,system level simulations are carried out using 3GPP Case 1 and Case 3 to evaluate the Relay performance in terms of capacity and coverage.(2) A resource allocation and interference coordinate scheme on the access and the direct link is proposed.The performance of the proposed scheme is examined by system level simulations.(3) To further increase the performance gain of Relayings,it is proposed in this document to use a new cell association scheme called range expansion (RE),in which a bias value for RSRP is used for cell selection. With RE,more users are associated by relay nodes.From the simulation results,it is concluded that when the RE bias value for RSRP is appropriate,the cell edge user data rate increases significantly without sacrificing the system average spectrum efficiency.(4) Based on the Relay system simulation platform, the throughput results for 1, 2,4,and10 RNs per cell are presented.For the purpose of evaluating the Relay performance,system average spectrum efficiency and cell edge user rate are adopted as the performance metrics.