Analysis Of Cooperative Wireless Backhaul Strategies In Heterogeneous Ultra Dense Network

Heterogeneous ultra dense network(H-UDN),where an ultra dense tier of small base stations(SBSs)is randomly embedded into the conventional macro cellular network to achieve the seamless coverage,is considered as one of the key technologies for the 5G and beyond network.By shortening the distances between users and base stations,the rate of users in H-UDN could be improved,which means that H-UDN has the ability to handle massive(1000 times)wireless data traffic.However,with the number of SBSs explosively increasing,the backhaul between the SBSs and the macro base station(MBS)is aggravating,which becomes the bottleneck of H-UDN.The flexible and convenient wireless backhaul is focused on,which has become a key issue in H-UDN.Nevertheless,the wireless backhaul would consume a large amount of wireless resources which are limited in H-UDN.Hence,the efficient wireless backhaul is concerned in H-UDN.Firstly,the novel cooperative wireless backhaul between SBSs is investigated in H-UDN,which could reduce the power consumption,increase the achievable rate and energy efficiency(EE)of the wireless backhaul.In cooperative wireless backhaul,the SBSs with good channel would help the SBSs with poor channel for wireless backhaul,which could take full advantage of the SBSs with good channel.Furthermore,the hierarchical model is proposed for the cooperative wireless backhaul,where the SBSs are divided into two groups according to the distances between the SBSs and the MBS.Then,based on the hierarchical model,the power consumption,achievable rate and EE of the cooperative orthogonal multiple access(C-OMA)wireless backhaul are derived and analyzed.Moreover,the upper bound and lower bound of EE are obtained.The simulation results shows that the C-OMA strategy could efficiently improve the performance of the wireless backhaul.Next,in order to improve the performance of cooperative wireless wireless,the cooperative non-orthogonal multiple access(C-NOMA)is introduced into wireless backhual.The power allocation and EE of wireless backhual in the C-NOMA strategy are presented.In the best hierarchical radius,the C-NOMA strategy has the priority over the C-OMA strategy,which is illustrated by the simulation results.Finally,through analyzing the advantages and disadvantages of both the C-OMA and C-NOMA strategies,the joint C-OMA and C-NOMA(JCC)strategy is proposed to further improve the performance of cooperative wireless backhual between SBSs.Due to the advantages of both the C-OMA and C-NOMA strategies,the JCC strategy achieves the best performance among all the strategies.