With next generation networks driving the confluence of multi-media,broadband,and broadcast services,Cognitive Radio(CR)networks are positioned as a preferred paradigm to address spectrum capacity challenges.CRs addre...With next generation networks driving the confluence of multi-media,broadband,and broadcast services,Cognitive Radio(CR)networks are positioned as a preferred paradigm to address spectrum capacity challenges.CRs address these issues through dynamic spectrum access.However,the main challenges faced by the CR pertain to achieving spectrum efficiency.As a result,spectrum efficiency improvement models based on spectrum sensing and sharing models have attracted a lot of research attention in recent years,including CR learning models,network densification architectures,and massive Multiple Input Multiple Output(MIMO),and beamforming techniques.This paper provides a survey of recent CR spectrum efficiency improvement models and techniques,developed to support ultra-reliable low latency communications that are resilient to surges in traffic and competition for spectrum.These models and techniques,broadly speaking,enable a wide range of functionality ranging from enhanced mobile broadband to large scale Internet of Things(IoT)type communications.In addition and given the strong correlation between the typical size of a spectrum block and the achievable data rate,the models studied in this paper are applicable in ultra-high frequency band.This study therefore provides a good review of CRs and direction for future investigations into newly identified 5G research areas,applicable in industry and in academia.展开更多
文摘With next generation networks driving the confluence of multi-media,broadband,and broadcast services,Cognitive Radio(CR)networks are positioned as a preferred paradigm to address spectrum capacity challenges.CRs address these issues through dynamic spectrum access.However,the main challenges faced by the CR pertain to achieving spectrum efficiency.As a result,spectrum efficiency improvement models based on spectrum sensing and sharing models have attracted a lot of research attention in recent years,including CR learning models,network densification architectures,and massive Multiple Input Multiple Output(MIMO),and beamforming techniques.This paper provides a survey of recent CR spectrum efficiency improvement models and techniques,developed to support ultra-reliable low latency communications that are resilient to surges in traffic and competition for spectrum.These models and techniques,broadly speaking,enable a wide range of functionality ranging from enhanced mobile broadband to large scale Internet of Things(IoT)type communications.In addition and given the strong correlation between the typical size of a spectrum block and the achievable data rate,the models studied in this paper are applicable in ultra-high frequency band.This study therefore provides a good review of CRs and direction for future investigations into newly identified 5G research areas,applicable in industry and in academia.
