Design And Implementation Of Interference Coexistence In Heterogeneous Cellular And D2D Networks

Ever since mobile communication have entered mobile internet era,the net traffic comes from mobile applications continues to become heavier,which makes higher requirement on carrying capacity and throughput of cellular base station.Device-to-Device(D2D)communication has been introduced into LTE-Advanced standard as an effective way to relieve base station payload and increase total throughput in network,and has become a solution to proximity communication in the 4th Generation mobile communications.However,a few new kinds of interference are produced while introducing D2D into LTE systems,which make interference coexistence technology a key point in the research of LTE-D2D heterogeneous networks.The thesis conducts thorough research on few key technologies about interference coexistence in LTE-D2D heterogeneous networks,including PDCCH blind decoding and LTE downlink channel estimation which are related closely to interference aware,and D2D resource allocation algorithms which accomplish interference control function.In the thesis,improved algorithms for every research item are brought up and tested in simulated platform.The innovation points of the thesis are:Firstly,based on the Viterbi path metric dominance PDCCH blind decode algorithm,a method refers to signal quality is presented in the thesis to overcome the difficulty in decoding PDCCH with low aggregation level.The presented algorithm on the one hand avoids bad impact on high aggregation level PDCCH decoding caused by low aggregation level decoding,and on the other hand assures the accuracy of low aggregation level decoding within a certain SNR range.Secondly,the thesis introduces an improved LTE downlink channel estimation algorithm based on VCFR addition and slide window noise elimination.The simulation results show that the presented algorithm beats other traditional channel estimation method in different kinds of slow channels.Thirdly,a mathematic model of LTE-D2D interference control suitable for realistic LTE systems is developed in the thesis.According to whether a resource block can be reused by more one pair of D2D users,the interference control problem is divided to two categories in this model:exclusive reuse problem and union reuse problem.The thesis gives optimal solution to the exclusive reuse problem,and a suboptimal greedy solution which is faster than the optimal one.As for the union reuse problem,an iterative algorithm based on exclusive reuse solution is presented.