Research On Resource Allocation Of Millimeter Wave Backhaul Networks

With the increasing demand for mobile services,higher spectral efficiency,energy efficiency and system capacity naturally become the pursued goal of the fifth generation of mobile communications(5G).Millimeter wave backhaul network,by virtue of its rich millimeter wave spectrum resources,can effectively improve the transmission efficiency of the system.Therefore,it has become one of the research hotspots of 5G.As the millimeter wave backhaul network is a resource constrained system,the most important issue is the problem of resource allocation.As a new type of communication network,the millimeter wave backhaul network is different from the traditional backhaul network in terms of network architecture,physical layer model,and so on,which will cause its resource allocation technology to be distinct with the traditional network.This paper gives an overview of the millimeter wave backhaul network and then introduces physical model and resource classification in the millimeter wave backhaul network.In addition,the resource allocation techniques suitable for millimeter wave backhaul network are proposed.This paper mainly focuses on resource allocation shcemes based on the concurrent transmission technology and load balance technique for the millimeter wave backhaul network.In summary,the main research work and innovation of this paper can be classified as follows:(1)In terms of the scheduling problem based on the concurrent transmission,this paper thoroughly studies the unfairness among the scheduling links and then proposes a fairness aware resource allocation algorithm in the spatial-temporal domain.In the algorithm,a utility function and a scheduling threshold are designed to maximize the system throughput with the fairness requirements satisfied.Besides,to quantify the impact of the scheduling algorithm on fairness,a Jain Index is proposed.(2)As for the research on the energy consumption due to the dense deployment of links,this paper puts forward the low energy consumption resource allocation scheme in spatial-temporal domain and power domain.In the scheme,based on the Shannon theory,a lemma is proposed which proves that the energy consumption is reduced eventually when the transmission time is increased with the total throughput remaining the same.According to the lemma and the concurrent transmission technology,this paper establishes the STDMA groups,and based on the STDMA groups,a joint time allocation and power control algorithm is proposed to achieve low energy consumption targets.In addition,a state indicator is designed to ensure the transmission order of the multi-hop links.The simulation demonstrates the superiority of the scheme in the system throughput and energy consumption.(3)In the aspects of the user resources allocation problem between the macro base station(MBS)and the small base stations(SBSs),this paper proposes a load balance scheme based on the improved Q-learning algorithm.By adding a virtual power bias to the SBS,more users can get access to the SBS to share the load of the MBS.Therefore,the bias value needs to be set reasonably to guarantee the backhaul efficiency of SBSs and the service quality of users.In this paper,a load balance scheme based on the improved Q-learning algorithm is proposed in which each MBS is an agent with independent learning and can get the optimal behavior,namely the optimal value of the power bias through a series of training.Besides,an improved behavior selection mechanism which is proved practicable is adopted to improve the learning efficiency and accelerate the convergence of the algorithm.