Research On Resource Allocation Technology For Wireless Virtual Networks Based On OFDMA Systems

The application of mobile users is gaining popularity at present and the amount and kinds of resource also grow rapidly, moreover, different applications require different amount of resource and also need to be satisfied with strict quality of service(QoS) requirement, thus an efficient resources allocation scheme with a specific management, which results in the wireless network virtualization. Wireless network virtualization becomes the natural next step aiming to provide mobile network operators(MNO) with the ability to control and manage their networks in a more dynamic fashion. Due to the characteristic of wireless channels, the virtualization of wireless networks presents many challenges.In the wireless networks, the MNOs can be distinguished into two types: the network infrastructure owners as physical MNOs(PMNO) and the MNOs renting resource from others are called virtual MNOs(VMNO). The essence of wireless network virtualization is to provide elasticity of resource allocation and is a pay-as-you-use business model, and it is just a form of resource renting. Meanwhile, VMNOs leasing resources from PMNOs provide more flexible and customized services and the enhanced QoS as well, which brings a win-win situation for both PMNOs and VMNOs. Therefore, how to achieve efficient and rational resource assignment in wireless environment is a key topic in virtualization aspect.This paper introduces game theory to research the wireless network virtualization scheme.Game theory has been widely applied as the theoretical basis and tools of analysis and solution to the conflict and cooperation. It can also solve the problem of the multiple rational decision-makers which have conflicts of interest in mutual influence, mutual constrains for all players to obtain the corresponding equilibrium which is the right solution for this subject. The problem of wireless resource allocation in single-cell orthogonal frequency division multiple access system(OFDMA) is mainly considered in this paper. According to the constraints between physical layers and MAC layers, a master-slave hierarchical structure to meet the needs of mobile users' resource amounts and QoS requirements based on Stackelberg game is constructed, which not only make PMNOs control the substrate resource more flexibly, but also can reasonably allocate the limited available virtual resource to VMNOs.The structure can dissolve the resource assignment problem, a joint optimization problem,into two parts, the optimization problem of physical layers and MAC layers. In consideration of the time-variant feature of wireless channels, this paper employs finite-state markov channel model(FSMC) to forecast the channel state information(CSI). Under this premise,the revenue functions of physical layers and MAC layer are established. Thus, the existence of Nash equilibrium point of the non-cooperative game among the virtual networks is proved that is addressed by a distribution iteration algorithm. Correspondingly, the substrate layer uses the branch and bound method to solve the subcarriers allocation problem.The simulation results demonstrate that the algorithm can obtain the equilibrium where both layers reach the best the strategy for themselves. The results demonstrate that the proposed algorithm is convergent. It can also realize the independent management requirement of virtual networks ensuring the effective use of resources and meet the constraints of QoS.