Resource Allocation Algorithms In Cognitive Relay Networks

With the rapid development of broadband access and application of mobile internet,traditional static spectrum allocation can no longer satisfy user requirement.Cognitive radio technology which can improve the spectrum utilization by supporting secondary Users(SU)to share licensed spectrum with primary user(PU)and avoid causing interference to PU’s normal communication by means of resource allocation and so on.On the other hand,relay communication can help source node selecting appropriate relay to improve spectrum efficiency and network coverage.Applying relay communication technology to cognitive radio can decrease power consumption and interference that SU causes to PU,while improve energy efficiency,throughput and coverage of cognitive radio.In this thesis,the gordian techniques and research status of cognitive relay network are studied,and the problems and challenges of resource allocation in cognitive relay network are surveyed.Based on these,two schemes are proposed to optimally allocate the resources for two different network scenarios.For resource allocation problem in a multi-hop scenario in cognitive relay network,a joint routing and resource allocation problem is investigated.A joint route selection and resource allocation algorithm based on route hops and energy efficiency is proposed.Firstly based on quality of service(QoS)requirement of SU,candidate route is confirmed.Then performing algorithm that based on energy efficiency maximum to obtain power control and sub-channel selection.Finally,the route which proposes maximum energy efficiency and its resource allocation scheme are selected.Taking route hops and energy efficiency as optimization objective,the proposed algorithm jointly considers QoS requirement,maximum power and user interference,which improving user transmission performance.For relay selection and resource allocation problem in cognitive relay network using mutual information accumulation,a joint relay selection and resource allocation algorithm based on power consumption minimization is proposed.The proposed algorithm confirms candidate relay based on user QoS requirement and performs relay selection and resource allocation based on transmission power minimum.The relay selection and resource allocation which proposes minimum transmission power are selected.The proposed algorithm jointly considers relay selection and resource allocation,realizing cognitive radio performance improvement.