Research On QoS-based Resource Allocation And Relay Crosslayer Optimization For Device-to-Device

Device-to-Device communication is a local communication on the licensed spectrum, whichcan help to compensate for the limitations of traditional cellular network in the system capacity,coverage and spectrum efficiency. When the D2D communication reuses the resource of a cellularuser with the non-orthogonal way, there will be amount of co-channel interference between them.To ensure the normal communication, a proper resource allocation method is necessary tocoordinate the interference. Therefore, the D2D communications resource allocation study has greatpractical significance.A QoS-based resource allocation scheme and algorithm is proposed in this thesis to control theinterference caused by the D2D communication introduced in cellular communication system, inwhich the D2D could reuse the uplink spectrum resource and correspondingly allocat resource ofcellular users in OFDMA according to its characteristics of short-range and low-power, while thesender has a sufficient input back-off (IBO). The simulation results show that this algorithm has abetter performance both in proportion to meet user target rate and on the average rate of D2D users.For the poor quality of cell edge user communications, in this thesis, mobile user equipment asrelay to support the D2D communication is studied, at the same time, an algorithm of joint relayselection and resource allocation is proposed to increase the capacity of cell edge usercommunications. This algorithm can not only increase the system capacity compare to the algorithmof direct resource allocation, but also achieve or exceed the performance of fixed relay, reduce theconstruction cost of the system, and especially increase the capacity of cell-edge user and improveits quality of service.Finally, a cross-layer optimization is designed in the D2D relay communication to solve itsseriously instantaneous channel fading, which combines adaptive modulation and coding at thephysical with a hybrid automatic repeat request at the data link layer. The simulation results provethat it can improve the average spectral efficiency, decrease the outage probability and enhance theadaptability and robust of D2D relay communication link.