A Study On Spectrum Allocation And Sharing Algorithm For Cognitive Radio Networks

In modern information society, a variety of emerging wireless communication technology is widely used. As a result, radio spectrum resources shortage becomes one of the main factors which constraints further development of wireless communications and is causing more concern from people. Except that the radio resource is occupied by different communication standards, another important reason for the wireless spectrum to be consumed is the lack of efficient spectrum management and allocation schemes. In this background, cognitive radio is considered as a new technology which can use the spectrum efficiently and is becoming the hot spot in the research field of wireless communication.This paper mainly focuses on the spectrum allocation and sharing technologies of cognitive radio. First, a brief introduction of cognitive radio technology is given, including its technical characteristics and research status both at home and abroad, etc. The details of cognitive radio system structure, dynamic spectrum allocation strategy and different spectrum allocation model are also introduced. Based on the in-depth study of the spectrum allocation algorithms using graph coloring theory model, an advanced graph coloring spectrum allocation algorithm is proposed. The algorithm increases the number of cognitive users which sharing the same sub-channel at the same time by updating the interference matrix dynamically, and avoids the interference to authorized users as well as adjacent cognitive users.Secondly, maximizing the network throughput is looked as optimization goal and corresponding algorithm is also proposed. This algorithm considers both cognitive user transmission throughput and sub-channel data transmission rate, and interference to authorized user is further avoided. Simulation results demonstrate that the advanced algorithm performs better in the aspect of spectrum utilization and allocation cost than other schemes of the same kind, and the average network throughput and sub-channel data rate of the optimization algorithm is also higher than that of the other allocation schemes.Finally, applying the ideas of dynamic channel allocation in cognitive radio to the multi-hop and self-organized wireless sensor network (WSN) can make full use of idle spectrum, reduce data collisions, and satisfy the new requirement of WSN for multi-media applications. In this paper a detailed analysis of WSN characteristics is stated, then aiming at the new concept, a low energy consumption WSN spectrum allocation scheme is proposed. The network structure suited for dynamic spectrum allocation WSN and low energy consumption sub-channel allocation algorithm are given. The algorithm realizes real-time transmission in WSN with large amount of data at the expense of smaller energy cost, and the channel allocation rules can meet the nodes'QoS requirements. Interference is reduced by setting the nodes'transmission power range and the limit on maximum transmission hops can relax the unnecessary network cost. Matlab simulation results show that under the premise of lower energy consumption, the algorithm achieves low probability of spectrum handoff, thus ensures a satisfying transmission success rate.