Research On Link's Demodulation Performance For D2D Communication

Direct communication between Device to Device (D2D) has great advantages in offloading traffic, improving network throughput and improving spectrum efficiency. It has attracted much attention from industry recently. The 3rd Generation Partnership Project (3GPP) has initiated the D2D work item as"LTE Device to Device Proximity Services (LTE_D2D_ProSe)",and continuously updated the Technical Reports of D2D. At present, the discussions of D2D are nearing completion. However, a clear target of the performance requirements of D2D device is advantage in achieving a consistent and predictable system performance and coexisting with other network systems, so the RF performance testing and specification of the D2D device is also an important part of standardization work.The demodulation performance of D2D link has a decisive impact on the D2D receiver's sensitivity and the demodulation of D2D physical channel.These two performance indicators are important parts of RF performance of D2D equipment, so the research on link's demodulation performance for D2D communication is necessary and the research work is also around the D2D link's demodulation performance.In this work, the reference measurement channel which is used to evaluate the sensitivity of D2D receiver is studied. The parameters of the reference measurement channel are analyzed firstly and two reference measurement channels are designed for D2D discovery and D2D communication respectively.A D2D simulation platform is built for simulation purpose. The simulation results can be used as an important reference for defining the sensitivity of D2D receivers in the standardization work. Besides, the performance of D2D receivers is analyzed and compared. Secondly, in the part of demodulation performance of D2D physical channel, the physical channel parameters of D2D are designed by analyzing and studying the four main physical channels of D2D.Five demodulation test scenarios are proposed and some simulations are deduced from them. The demodulation performance of D2D channel and D2D communication channel is simulated by testing cases respectively. The study work not only evaluates the influence of time-frequency offset and retransmission with soft-combining on channel demodulation performance,but also compares the demodulation performance between different channel models. The results of channel's demodulation performance can also be used as a reference for 3 GPP standardization work.Extending the network coverage is a main purpose in D2D enhancement.Based on the study of D2D link's performance, especially the demodulation performance of D2D discovery channel (PSDCH), this work studies the Sidelink Reference Signal Received Power (S-RSRP) process which is based on PSDCH demodulation and evaluates the influence of different SNRs on the success rates of PSDCH demodulation. Then, the results and performance for S-RSRP measurements in different channel models are simulated. In the end,the relay UE selection schemes based on S-RSRP is studied and compared with each other. In order to achieve dynamic tradeoff between resource utilization and end-to-end performance, a relay UE selection scheme with RSRP threshold is proposed.