Game-Theoretic Spectrum Resource Management For Femtocell Networks

Recently, wireless cellular network has experienced an explosive growth in data traffic, with the rapid development of communication technology and the widespread popularity of mobile devices. To meet the increasing demand, femtocell is a trend for more flexible and economical deployment of infrastructure. In the past decade, femtocell technology has attracted many attentions due to its advantages of capacity improvement.Femtocells are envisioned as an effective solution for satisfying the demands of highly increasing quality-of-service and personalized wireless services. Generally, a femtocell is a small, low-power cellular base station, typically designed for use in a home or small business. Hence, femtocells significantly improve the spectrum space efficiency and dramatically increase the capacity of cellular network. A main challenge in the deployment of femtocell is spectrum resources management, which deeply effects the thoughput of cellular network. By using the tool of game theory and optimization, several issues are studied in this paper, including the frequency reuse in self-organized dense femtocell network, spectrum allocation in the heterogeneous cellular network, and the joint optimization of user association and interference coordination. The main contributions are summarized as follows.Firstly, a game theory based distributed frequency reuse method is proposed, considering that the tranditional network plannings are difficult to implement and the spectrum efficiency is low due to the random of the deployment of femtocells. After a femtocell network is divided into several femtocell clusters by distributed methods, the proposed method consists of two components: negotiation inside a cluster and inter-cluster game-theoretical mechanism. Through employing the proposed method, spectrum can be effectively reused in femtocell networks. The average capacity of the network is considerably increased by adopting the proposed method.Secondly, the spectrum allocation in the heterogeneous cellular network is studied. A joint strategy of spectrum allocation and pricing is proposed based on Stackelberg game, which inspires the users to install femtocells and open their services. Through modeling the competition between base stations and users, the relationship between spectrum price and users’ demands is analyzed. Through modeling the competition between macrocell and femtocells, the optimal strategy of spectrum allocation and pricing is proposed for the two-tiered hierarchical cellular network. Spectrum resources can be reasonably allocated between macrocell and femtocells, and their utilities are maximized by achieving the proposed method.Thirdly, a dynamic optimal spectrum allocation method is proposed based on evolutionary game and dynamic programing, considering the dynamic competitions between macrocell and femtocells and even among users. A two-level framework is proposed by jointly considering users’ dynamic service selection and provider’s spectrum allocation. The users’ service selection is modeled as an evolutionary game, and the spectrum allocation is modeld by dynamic programing. The spectrum resources are dyanmiclly and optimally allocated between the macrocell and femtocells. Theoretical analysis and simulation results both show that dynamic heterogeneous cellular networks reach an equilibrium point by achieving the method.Finally, a game theory based distributed method of user association and interference coorination is proposed for the heterogeneous cellular netowrk. The existence of the equilibrium point achieved by the proposed method is proven. The problem is modeled as a Stackelberg game, which consists of channel assignment, biasing and power allocation. As the leader, the macrocell keeps silent on some channels for reducing interference to motivate the femtocells to adapt macro users. As the followers, femtocells operate with biasing to accommodate macro users. Meanwhile, both the macrocell and femtocells optimally allocate the transmit power over channels. Efficient algorithms are proposed for the macrocell and femtocells making strategies, respectively. The proposed methods significantly improve the network performances, compared with the existing methods.