Investigation Of Relay Route Selection Strategies For LTE-A Cellular Networks

LTE-Advanced system aims at supporting higher data rates and higher spectral efficiency. In addition to adopting OFDM, MIMO and other key technologies in the physical layer, LTE-Advanced also introduced relay technology. Multi-hop cellular network, which integrates relays into the traditional cellular network, is currently the most promising network having high performance and low cost. By introducing one or more relay nodes (RN), the base station (eNB) signals can be processed by every RN before sent to the user equipment (UE). This multi-hop transmission can extend coverage, enhance system throughput and improve cell-edge performance. With the introduction of relay technology, however, many challenges are also produced, such as the UE routing issue. In the LTE cellular network with relays, UE can flexibly select transmission routes for the possible direct or multihop transmission. Therefore, choosing an effective Relay Route scheme has become a key factor affecting system performance.According to various simulation scenarios in 3 GPP proposals and system-level simulation method, combined with the parameter requirements of 3 GPP protocol, this thesis firstly builds up a system-level simulation platform based on relay LTE-A cellular network using IT++tools. This platform lays a foundation for later research on LTE-A cellular network with relays.Next, three kinds of common routing schemes are investigated based on signal power (PW), signal to interference plus noise ratio (SINR) and effective spectrum efficiency (SE). Simulation and analysis on performances of cell average throughput, cell edge throughput and computational complexity have been carried out based on system-level simulation platform. Then an improved PW scheme which combines PW scheme and SINR scheme is given. The complexity of the improved scheme is far less than the SINR scheme but with similar performance. Then based on the fact that the scheduling of UE is limited in practice, a balanced scheduling SINR (BSSINR) algorithm is proposed. In the case of limited scheduling, compared with the SINR scheme and SE scheme, the BSSINR algorithm has no significant increase in computational complexity, but the system throughput significantly improved. In addition, the thesis also discusses some relay selection related issues, such as the application of cooperative relay in LTE-A relay cellular network, further improvement of the SE selection scheme and the impact of location RN on performance.