Research And Simulation Of Cognitive Radio Technology In Heterogeneous Network

Due to the rapidly growth of the user demand, the wireless network technology has a great development in recent years. These heterogeneous network provide convenient and high-quality communication. While at the same time, they also increase the demand of spectrum resource. It becomes more and more serious because the amount of spectrum resource is limited. It is not a problem that there is no spectrum to use, but a problem that the spectrum utilization is very low. This is the result of current fixed spectrum allocation method. This dilemma can be solved if we select a dynamic spectrum allocation to allow the unlicensed network share the licensed spectrum with the licensed network. One of the research direction is cognitive radio technology. The cognitive user can sense the idle spectrum which is not occupied by this technology. Then it can utilize the spectrum temporarily and improve the spectrum efficiency.This paper discusses the cognitive radio technology in the scenario which is consisted of heterogeneous networks. Firstly, we propose a spectrum sharing scheme in this scenario. The scheme has a multi-level structure of joint radio resource management and several modules. Then we discuss the spectrum sensing technology. We provide a collaborative hybrid sensing algorithm for the scheme. The algorithm contains single sensing and collaborative judging. We give a simulation for the performance of the algorithm. Next, we come up with a spectrum allocation algorithm by fully considering the bandwidth matching and the interference avoidance on the base of graph coloring. It is used by the scheme’s allocation part. We present objective function, label rule and performance metrics for the algorithm. The simulation is also done by comparing with other two algorithms. Finally, we build a heterogeneous network simulation platform to evaluate the whole scheme’s performance in four aspects, that is the number of satisfied users, the SINR distribution of satisfied users, the total throughput and the total spectrum efficiency.