Research On Transport Resource Scheduling And Optimization Based On Hierarchical Multiplexing

With the increasing demand for group-oriented large-scale accesses and high-rate services,multi-cast transmission,which has a natural advantage in this respect,has been the focus of researchers.But its wide applica-tions were always limited by the spectrum utilization by the users with the most severe channel condition.In recent years,non-orthogonal multiple ac-cess(NOMA)access,Layered-division Multiplexing(LDM)and other non-orthogonal multiplexing technologies have further increased user access and enhanced spectrum utilization.These non-orthogonal multiplexing schemes have also brought new vitality and vigor to broadcast and multi-cast.The non-orthogonal layer multiplexing based broadcast and multi-cast scheme mainly utilize the difference of channel condition and coding gain to im-prove the spectrum utilization,so the power distribution between different layers and the transmission modulation coding scheme are critical issues,so this paper mainly studies the non-orthogonal transmission resource alloca-tion optimization of broadcast and multi-cast scheme.In this paper,the transmission resource allocation optimization problem of non-orthogonal hierarchical transmission is firstly studied to improve the spectrum efficiency of the system.Firstly,the model of the layered trans-mission problem is established and further optimized.Then,a simplified two-layer power distribution optimization scheme based on user assignment is presented and the power distribution optimization algorithm suitable for multi-layer is further proposed.In order to improve the practicability and reduce the complexity of the algorithm,we propose a discrete optimization algorithm based on dynamic programming,which can efficiently solve the optimal discrete power distribution and the corresponding adaptive modu-lation and coding scheme.In the analysis and verification of simulation re-sults,the proposed algorithm is compared with traditional multi-cast scheme and other non-orthogonal layered multiplexing power allocation schemes,which proves the effectiveness of the proposed multi-layer user grouping power allocation algorithm.At the same time,it is verified that the com-plexity of complexity of the proposed dynamic programming algorithm com-pared with traditional algorithms is reduced from(²²+^-1-2)to((+)),and compared with other user-assignment-scheme based algorithms,it can improve the spectrum utilization by 15%.This paper also further studies the non-orthogonal broadcast multi-cast transmission framework based on layered-division multiplexing to im-prove the transmission efficiency of MBSFN(Multicast Broadcast Single Frequency Network)mode in the e MBMS(Evolved Multimedia Broadcast Multicast Service).In order to optimize this non-orthogonal layered multi-plexing broadcast multi-cast transmission framework,this paper combines the power allocation of non-orthogonal layers with phase optimization,and models the problem as a weighted max-min(MM)problem considering the fairness of each subregion.Since this problem is a non-convex optimiza-tion problem,this paper first evaluates the upper performance bound of the framework by solving the relaxed convex problem,and obtains the subopti-mal solution of the optimization problem by using a semi-definite relaxation algorithm based on Gaussian randomness.Secondly,in order to further op-timize the transmission efficiency and reduce the degradation of the semi-definite relaxation algorithm caused by the expansion of the network scale,an optimization scheme based on the Constrained Concave-Convex Proce-dure(CCCP)is proposed,and the feasible initial solution searching scheme under the poor channel conditions are given.Finally,the algorithm simula-tion is given.The results show that in large-scale networks,the proposed al-gorithm based on the constrained bump process can achieve a signal-to-noise ratio gain of 5 d B compared with the traditional algorithm based on Gaussian randomization.At the same time,the simulation results also prove that the non-orthogonal multiplexed multi-cell cooperative transmission framework can achieve up to 25%enhancement layer spectrum utilization improvement compared to the traditional orthogonal multiplexed multi-cell transmission framework.