Research On Dynamic Resource Optimization Based On Licensed Or Unlicensed Spectrum Access

With the rapid development of Internet of Things and mobile Internet,the influx of massive intelligent terminals and the requirement of high quality of service of users,the existing networks can not bear the traffic demand of thousands of times.Heterogeneous small cell networks technology is a promising technique to improve the coverage and capacity of cell edge users.Due to the limited resource of licensed spectrum and the potential of unlicensed spectrum(e.g.,spectrum used by WiFi)to significantly improve the performance of the cellular networks,the research on unlicensed spectrum(e.g.,LTE-U)of heterogeneous small cell networks attracts much attention in both academia and industry.Orthogonal channel access in orthogonal frequency division multiple access is becoming a limiting factor of spectrum efficiency since each subchannel can only be utilized by at most one user in each time slot.Thus,non-orthogonal multiple access(NOMA)has been regarded as a promising technology to relieve the heavy burden of overloaded traffic in base station.This paper studied the resource optimization of unlicensed spectrum and NOMA technology in heterogeneous cellular networks to achieve green resource allocation.This paper mainly investigated the problem of dynamic resource optimization and allocation of licensed spectrum and unlicensed spectrum.We investigated the resource allocation in licensed/unlicensed spectrum sharing heterogeneous small cell networks by considering co-tier/cross-tier interference caused by spectrum sharing in licensed and unlicensed spectrum,respectively,taking the user's quality of service requirements and the user's maximum transmission power as constraints,and ensuring the unique channel allocation of the same small cell base station.By introducing the Lyapunov optimization framework,three buffer queues are established,and the optimization problem based on energy efficiency is converted into three sub-problems.The problem of subchannel allocation and power distribution is finally solved.In NOMA network by means of software defined network technology,one user can receive signals from the BS through arbitrary virtual resource blocks(VRB)and one VRB can be allocated to multiple users at the same time.We proposed a suboptimal VRB assignment algorithm based on the two-side matching method.We considered the energy efficient of the network as optimization function and we formulated the power allocation as a mixed integer programming problem.In the single NOMA network,We proposed a suboptimal subchannel assignment algorithm based on the two-side matching method.We formulated the power allocation as a mixed integer programming problem by considering minimum QoS requirement,and maximum power constraint.In the downlink of the multiple NOMA network,based on the framework of Lyapunov optimization,the problem of energy efficient optimization was broken down into three subproblems,two of which are linear and the rest of which be solved via Lagrangian optimization.Simulation results are presented to verify the convergence and the effectiveness of the proposed algorithms.