Self-Optimization Mechanism Of Resource Assignment And Load Balance In Wireless Access Network

As the development of technology in wireless network, the automation of network optimization has become a necessary trend so as to make the vendors manage the increasingly complex network more efficiently while achieving a high-quality and low-cost network operation. As a part of the self-optimization technologies, the self-optimization of resource assignment is considerably important. Both the admission control before user accessing to the network and packet scheduling after user accessing to the network affect the users experience directly. Moreover, as a consequence of variability of the users’service requests in both of the time and the space domain, the load distributions are always nonuniform inside of the single homogeneous network and among of the heterogeneous networks, which lower the network performance directly. Therefore, research on the self-optimization mechanisms of wireless resource assignment and load balance is a quite meaningful work.Regarding the self-optimization of admission control, as a consequence of basic realization of wireless IP-based services, the traditional admission control mechanism based on the random process cannot give a real-time response to the incoming traffic burst. Hence this paper researches the self-optimized admission control mechanism adopting for self-similarity service in wireless network in order to improve the access capacity in wireless network with the QoS(Quality of Service) ensuring. Regarding the self-optimization of packet scheduling, coverage and capacity are two key indicators. The traditional packet scheduling algorithm cannot efficiently adjust the fairness between edge users and central users, which means the requirement of balancing between coverage and capacity cannot be satisfied. Hence it is necessary to research the novel packet scheduling algorithm for wireless capacity and coverage optimization so as to get the efficient resource utilization in wireless network. Regarding the self-optimization of load balance in the homogeneous network, although the traditional load balance technologies based on the adjusting in engineering parameters are efficient and eased of implementation, they are always not energy-efficient and easy to bring the inter-cell interference. Hence this paper introduce a new method of extending the coverage range to balance load, which also can overcome the problem of performance decreasing caused by interference at the same time. Regarding the self-optimization of load balance among the heterogeneous networks, the previous load balance methods are driven by the coverage, capacity and quality without considering the match between the network performance and user experience. And as the developing requirement on the green communication, it is necessary to research the energy efficient driven load balance mechanism. The purpose of this kind of load balance method is to make the traffic distribution more reasonable among the different RATs (Radio Access Networks) and improve the mobile BS energy efficiency and degree of the user satisfaction. The main contents of this paper are as follows: For the self-optimization of CAC (Call Admission Control), firstly the service similarity in the wireless network are researched and the service bandwidth was calculated with similarity and QoS parameters. Then an SS-CAC (Self-organized based on network Similarity Call Admission Control) mechanism based on the service bandwidth optimization was introduced which aims to lower the system bandwidth utilization and service rejection probability. And the novel mechanism was achieved and simulated. Compared with traditional CAC, the results of simulation show the performance of SS-CAC mechanism can not only ensure the quality of the voice service but also save the bandwidth utilization of the data service by2.69%. In addition, it can reduce the call rejection ratio and call drop ratio by0.95%and2.81%respectively in the case of the high cell load.For the self-optimization of packet scheduling, it firstly introduces a novel β-CCPF (β-Coverage and Capacity Proportional Fairness) scheduling algorithm for network CCO (Coverage and Capacity Optimization) on the basis of enhancing the fairness of edger users schedule priority. Then it proves the theoretical convergence of this algorithm and proposes a coverage-capacity optimization scheme on the basis of this algorithm, traffic distribution and power adjustment. This scheme is simulated in an experimental regular scenario and a real non-regular scenario respectively. The results show that in the use case of CCO, the novel algorithm can ensure the reasonable ROR (Resource Occupation Ratio) and make the mean user throughput increased by19%and33%compared with the a-PF (α-Proportional Fairness) algorithm in the experimental and real scenario respectively.For the self-optimization of load balance in the homogeneous network, it firstly proposes a load-balancing strategy that uses CoMP (Coordinated Multiple Points transmission/reception) technology among the BSs (Base-Stations). Different patterns of load-balancing based on CoMP are defined and discussed by modeling on the CoMP channel and network traffic. It also defines two QoS metrics to be guaranteed during CoMP load balancing:call blocking rate and efficient throughput. The closed-form expressions for these two QoS metrics are derived. The load-balancing capacity and QoS performances with different CoMP patterns are simulated and evaluated in the system with low-dense and high-dense distribution of the high-loaded BSs. The numerical results present the reasonable CoMP load balancing pattern choice with guaranteed QoS in each system. The simulation results show in the case of2%call blocking rate requirement, the most suited CoMP load balancing pattern can improve the cell edge user’s efficient throughput by38.2%and the maximum allowed traffic volume per base-station by27.8%in the system with high-dense distribution of the high-loaded BSs.For the self-optimization of load balance among the heterogeneous networks, firstly the characteristics of the resource assignment in LTE and WiFi network are analyzed. The energy efficiency of mobile BS and the degree of user satisfaction are defined as the optimization objections of the load balance among the heterogeneous networks. Then it introduces the balanced edge users’handover conditions needed to be satisfied during the load balance process. Following these conditions, the detailed load balance algorithm is designed based on the adjustment in the handover quality offset. The final simulation experiment verifies that the load balance algorithm can effectively balance the resources utilization among the heterogeneous networks and the BS’s energy efficiency can be improved by11.14%compared with the case before load balancing in the case of ensuring the degree of user satisfaction.