Research On Resource Allocation Algorithm In Ultra-dense Networks

Ultra Dense Networks(UDN)deploying low-power access points to meet the actual demand in the coverage of current macro base stations greatly improves the spectral efficiency of the system and is one of the key technologies to realize the target of 1000 times capacity improvement in the future 5G networks.However,the large deployment of access points shortens the distance between base stations and also brings about serious inter-cell interference,which seriously hinders the improvement of system capacity.Faced with this problem,Corrdinated Multiple Points(CoMP)technology aims to reduce or even eliminate co-channel interference between base stations by sharing useful information such as channel status and user data among the collaborative base stations.The UDN based on CoMP technology is an important means to realize the high frequency efficiency and high energy efficiency requirements of the future mobile communication system.Although the UDN based on CoMP technology shows obvious advantages in improving the utilization of wireless resources,the increase in the number of access points in the network and the complex inter-site cooperation mechanism make this new type of network combined with the CoMP transmission strategy faceing severe challenges in wireless resource management and optimization.A reasonable and effective allocation of wireless resources is a prerequisite for the full utilization of wireless resources in the network.Therefore,the search for a more flexible and efficient wireless resource allocation optimization method for the characteristics of the network has important research value for utilizing the advantages of the UDN and CoMP technology.In view of this,this thesis takes the UDN based on CoMP technology as the research object,aims at improving the utilization of wireless resources of the system,and focuses on the joint optimization of frequency and power resource allocation for the system's spectrum efficiency and energy efficiency.The full text of the key research is as follows:1.Research on resource allocation optimization oriented to spectrum efficiency.From the perspective of maximizing the utilization of space resources,taking into account the limit of transmit power of each base station in the network and the fairnessof users,and taking the total data rate of the system as the ultimate goal,a joint optimization mathematical model of frequency and power distribution in the UDN based on CoMP transmission technology is established.According to the established model,a resource block(RB)allocation algorithm based on diversity multiplexing compromise is proposed,which improves the system performance by utilizing the flexible allocation of space resources.Based on this,a power distribution algorithm based on Newton method is proposed and the joint optimization of frequency and power is realized.2.Research on resource allocation optimization oriented to energy efficiency.In the UDN based on Dynamic Cell Selection(DJT)CoMP,energy efficiency per energy bit is defined and the goal is maximize the system energy efficiency,and establish a multi-dimensional resource allocation optimization model considering data rate,user fairness and energy efficiency.In addition,in order to avoid the serious data transmission quality degradation due to the energy saving,the established optimization problem also includes the restriction of the quality of service(QoS)requirement of users.According to the established model,a centralized RB allocation algorithm based on cross-entropy is proposed.Finally,the algorithm performance simulation shows that the proposed algorithm has higher system average energy efficiency than greedy algorithm and distributed resource allocation algorithm based on JT CoMP.