A Study Of Relay Selection Algorithms Based On D2D Communication

Device-to-Device communication technology based on LTE-A is maturing with thedevelopment of LTE-A system. An effective relay selection algorithm has a great impact inimproving link quality and spectrum utilization. Research of relay selection mechanisms is ofcrucial importance in hybrid network of D2D underlay cellular network communication.This thesis firstly introduces the LTE-A architecture, physical layer transmission scheme andthe corresponding frame structure. Then it analyses characteristics of hybrid system based onLTE-A in3different scenarios, introducing D2D relays between D2D links in hybrid network ofcellular and D2D users, between links from cellular users to eNodeB in cellular network and inD2D multi-hop communication, and designs relay selection schemes for each scenario.This thesis focuses on the relay selection mechanisms in each scenario. A semi-distributedrelay selection algorithm based on Selection Region Level and a centralizedGeographical-Information based relay selection algorithm are proposed for D2D links in hybridnetwork and cellular links in cellular network, respectively. These two strategies simplify relayselection progresses and reduce link failure probability since the relay link is introduced aiming atprotecting link quality. For new arrival D2D communication requests, it proposes aneNodeB-assisted multi-hop relay selection algorithm, minimizing the number of hops as well asinterference and improving spectrum efficiency.With a simulation of the proposed mechanisms in each scenario, by comparing the linkfailure probability and relay selection complexity, the proposed strategies prove advantageousover conventional relay selection strategies in the scenarios.