A Study On Small Cell Resource Allocation Algorithms In Mobile Cellular Networks

Small cell technology is regarded as one of the indispensable technologies in future mobile cellular communication system. The introduction of small cells in a mobile cellular network can significantly enhance the network capacity, optimize network coverage, and provide users with a better quality of service. But at the same time, the introduction of small cells in a cellular network also brings the corresponding interference problem. How to address the interference problem through efficient resource allocation has become an important research topic in mobile cellular networks.This thesis studies the small cell resource allocation problem in mobile cellular networks, proposes two small cell resource allocation algorithms for different system scenarios.First, the thesis introduces the concepts, classifications and requirements of small cells, and then analyzes the spectrum resource allocation problem in small cells and the major interferences between macro cell users and small cell users. Two basic spectrum resource allocation methods are also introduced.Then, the thesis proposes a clustering based downlink spectrum allocation algorithm for a system scenario with a single macro cell and multiple small cells. The algorithm introduces a new clustering method to improve the system throughput. It consists of two phases, namely clustering phase and spectrum resource allocation phase. In the clustering phase, the algorithm divides all small cells into several clusters based on three principles and allows a small cell to belong to more than one cluster. Once the clustering is completed, the priority of each small cell is determined. In the spectrum resource allocation phase, according to the result of clustering and the priority of each small cell, the algorithm allocates the downlink spectrum resources to all users in the system following several principles. Simulation results show that compared with an existing clustering based resource allocation algorithm, the proposed resource allocation algorithm can effectively improve the throughput performance of the system.Finally, the thesis proposes a resource allocation algorithm for a single-cell system scenario with a limited backhaul network. The algorithm can be used to perform both spectrum resource allocation and power resource allocation for small cell users. It consists of a clustering based spectrum resource allocation algorithm and a game theory based power resource allocation algorithm. For spectrum resource allocation, the clustering based spectrum resource allocation algorith first divides all small cells into several clusters and the clustering procedure is similar to that in the proposed clustering based downlink spectrum allocation algorithm. On the basis of the clustering result, each cluster selects a small cell as the backhaul node. Then spectrum resources are allocated to each small cell user. For power resource allocation, the game theory based power allocation algorithm first builds a game model between macro cell users and small cell users. Then, power resources are allocated to each small cell user by solving the game model and making the game reach a state of equilibrium. Simulation results show that the proposed resource allocation algorithm can effectively improve the throughput of macro cell users and the fairness of small cell users compared to the proposed clustering based downlink spectrum resource allocation algorithm. Meanwhile, it outperforms two existing resource allocation algorithms in terms of system throughput.