Radio Access Control In Radio Resource Management Of Heterogeneous Wireless Networks

With the rapid development and popularization of wireless network access technology, there has been a variety of wireless network systems, such as mobile cellular networks, wireless personal area network, wireless LAN, wireless MAN etc. At the same time wireless access capabilities of user’s terminal equipments expand constantly. There has been lots of terminal equipments that support a variety of wireless network accesses. Often in a heterogeneous wireless network composite environment, the same terminal equipment at the same point of time and geographic location has greatly increased the access ability of users joining network at any time and place. Meanwhile, it has brought many new challenges in the management of wireless network resources. How to take advantage of the complementary nature of heterogeneous wireless networks to make an organic whole of various wireless networks, to fully share the network resources, and together to provide users with excellent and transparent network access services that no independent wireless network can compare? It has become an urgent need to solve these problems in the development of heterogeneous wireless networks.Resorting to probability theory, dynamic programming, stochastic optimal control methods and theories, this paper demonstrates an in-depth research around the pricing of network resources in heterogeneous wireless networks and access control issues. The author firstly solves the problem of optimal pricing in heterogeneous wireless networks catering both primary users and secondary users. Then the author proposes a pricing based static joint opportunistic radio access control policy. At last an optimal dynamic joint stochastic radio access control policy is proposed to deal with the scenario that system state transition reward is not a linear function of secondary user access probability. Simulation results show that the utilization of network resources and consolidated income of the system are effectively improved.The main content of the thesis is shown below.1. Firstly, the author makes a detailed analysis of pricing issue in heterogeneous wireless networks, and then for the first time extends optimal pricing issue of single network servicing both primary users and secondary users to heterogeneous network system. The author proposes a solution of optimal pricing based on the states of system in heterogeneous networks through stochastic dynamic programming. The simulation results show that a reasonable primary user blocking punishment would encourage more secondary users to try to access network therefore generating more revenue. Compared with the optimal pricing policy proposed by other literatures, the system overall income has increased by11%.2. To solve the problem of the radio access control policy of secondary users in joint radio access control entity, the author analyzes the impact of service qulity of system overall income when different accessing probabilities of each network of the heterogeneous network system are adopted. The author combines this joint radio access control problem with optimal pricing and calculates the optimal accessing probability through stochastic dynamic programming and optimal control theories. Simulation results show that primary user blocking rates are effectively under control and system revenue is further improved under optimal accessing probability. Compared with other joint radio access control algorithms, our scheme serves20%more secondary users and improves system overall income by10%at least.3. When studying network load based joint radio access control algorithms, the author discovers that when the state transition revenue function and access probability demonstrate a non-linear relationship, the traditional deterministic access control method can no longer make a maximized revenue of the system, i.e. the behavior of the secondary users selecting host network based on network load status should no longer follow a deterministic manner. The thesis introduces a dynamic stochastic access control method based on the state of the network load. This strategy provides an optimal access probability for each state of the system inside an access probability space. Experimental simulation results show that the dynamic stochastic radio access control policy can greatly improve the system gain and optimize the efficiency of wireless network resources usage by agilely dispatching secondary users to more expected host network predefined.4. Finally, this paper describes the user arrival rate self-adaptive problems in stochastic access control policy. The network model in Chapters Ⅲ and Ⅳ assumes that the heterogeneous sub-network’s primary user arrival process is independent of each other and at a fixed rate as Poisson process. However in actual network scenarios, the arrival rate of primary user is often changing with the passage of time and therefore unpredictable. Based on Chapters Ⅲ and IV research, the author introduces user arrival rate adaptation algorithm to joint access control in heterogeneous network in order to guarantee timely adjust to actual arrival rate of the primary users and the lease price of network resources, so that the system revenue can be maximized. This method further optimizes the two algorithms aforementioned. Experiment results show that user arrival rate adaptive method effectively decrease primary user blocking count by20%therefore increases system overall revenue.