Research On Spectrum Allocation In Cognitive Radio Sensor Networks

With the wide application of wireless devices in recent years,the growing demand for spectrum resources has been more and more.However,the reality is that many bands have been assigned to certain users(as the primary user),and the other users should share the public bands.What’s more,with the increasing of the primary users,the licensed available spectrum is faced with the situation of exhausted.Many studies show that the licenced channels in the dimensions of time and space have a lot of spectrum holes which leads to low utilization of spectrum.The contradiction of spectrum scarcity with low utilization of spectrum is becoming fiercer and fiercer.In order to solve the problem,researchers have brought the concept of cognitive radio,which is using software to control the access of the spectrum.With cognitive radio,secondary users can opportunistically access the licenced spectrum when sensing that primary users are absent.Although cognitive radio have been studied for many years,it still needs to do much extensive and in-depth research because cognitive radio has involved many areas.In this paper,we will study two spectrum allocation stategy in cognitive radio sensor network,which is based coopertion by relay pairing and non cooperation by interference suppression.In this paper,we first put forward a kind of spectrum allocation strategy based on relay cooperation.In this model,we focus on cooperative spectrum access in a cognitive radio networks(CRN),where secondary users(SUs)serve as relays for primary users(PUs)to improve their throughput,and in return SUs can gain transmission opportunities.To optimize the overall utility of a cooperative CRN,we first investigate the cooperation between a single pair of PU and SU with Stackelberg game model,where PU determines access time allocation while SU determines relaying power for the PU.Based on the analytical results,cooperation pairing between multiple PUs and SUs is modeled as a bipartite matching problem and solved using Gale-Shapley algorithm.Numerical results demonstrate that,with the proposed schemes,overall utility for PUs and SUs can bebalanced with low computational complexity.Then we study the allocation stategy in the cognitive radio network with interference suppression.In this model,secondary users can work coexistence with primary user by control the accumulated interference under the interference temperature of the corresponding primary user.The centralized spectrum allocation in this model is formulated as a multiple multidimensional knapsack problem.This paper will propose an exact solution algorithm and a heuristic algorithm.Numerical results demonstrate that,two algorithms let secondary network get a very high throughput rate,and the exact solution get more but the heuristic algorithm with low coplexity.Finally,this paper put forward some shortcomings of this paper and introduced some future works.