The spectrum sensing problem has gained new aspects with cognitive radio and opportunistic spectrum access concepts. It is one of the most challenging issues in cognitive radio systems. In this paper, a survey of spectrum sensing methodologies for cognitive radio is presented. Various aspects of spectrum sensing problem are studied from a cognitive radio perspective and multi-dimensional spectrum sensing concept is introduced. Challenges associated with spectrum sensing are given and enabling spectrum sensing methods are reviewed. The paper explains the cooperative sensing concept and its various forms. External sensing algorithms and other alternative sensing methods are discussed. Furthermore, statistical modeling of network traffic and utilization of these models for prediction of primary user behavior is studied. Finally, sensing features of some current wireless standards are given.

A survey of spectrum sensing algorithms for cognitive radio applications

https://www.cs.montana.edu/courses/csci566/Ref/WMSN-Survey.pdf

A survey on wireless multimedia sensor networks

Cooperative spectrum sensing in cognitive radio networks: A survey

Cognitive radio networks will provide high bandwidth to mobile users via heterogeneous wireless architectures and dynamic spectrum access techniques. However, CR networks impose challenges due to the fluctuating nature of the available spectrum, as well as the diverse QoS requirements of various applications. Spectrum management functions can address these challenges for the realization of this new network paradigm. To provide a better understanding of CR networks, this article presents recent developments and open research issues in spectrum management in CR networks. More specifically, the discussion is focused on the development of CR networks that require no modification of existing networks. First, a brief overview of cognitive radio and the CR network architecture is provided. Then four main challenges of spectrum management are discussed: spectrum sensing, spectrum decision, spectrum sharing, and spectrum mobility.

/pdf/a-survey-on-spectrum-management-in-cognitive-radio-networks-p8ekergqia.pdf

A survey on spectrum management in cognitive radio networks

Cognitive radio (CR) technology is envisaged to solve the problems in wireless networks resulting from the limited available spectrum and the inefficiency in the spectrum usage by exploiting the existing wireless spectrum opportunistically. CR networks, equipped with the intrinsic capabilities of the cognitive radio, will provide an ultimate spectrum-aware communication paradigm in wireless communications. CR networks, however, impose unique challenges due to the high fluctuation in the available spectrum as well as diverse quality-of-service (QoS) requirements. Specifically, in cognitive radio ad hoc networks (CRAHNs), the distributed multi-hop architecture, the dynamic network topology, and the time and location varying spectrum availability are some of the key distinguishing factors. In this paper, intrinsic properties and current research challenges of the CRAHNs are presented. First, novel spectrum management functionalities such as spectrum sensing, spectrum sharing, and spectrum decision, and spectrum mobility are introduced from the viewpoint of a network requiring distributed coordination. A particular emphasis is given to distributed coordination between CR users through the establishment of a common control channel. Moreover, the influence of these functions on the performance of the upper layer protocols, such as the network layer, and transport layer protocols are investigated and open research issues in these areas are also outlined. Finally, a new direction called the commons model is explained, where CRAHN users may independently regulate their own operation based on pre-decided spectrum etiquette.

/pdf/crahns-cognitive-radio-ad-hoc-networks-1odtmohw8e.pdf

CRAHNs: Cognitive radio ad hoc networks

https://www.cs.montana.edu/courses/csci566/Ref/CR-Survey.pdf

NeXt generation/dynamic spectrum access/cognitive radio wireless networks: a survey

s A Mobility Prediction Architecture Based on Contextual Knowledge and Spatial Conceptual Maps Nancy Samaan and Ahmed Karmouch, IEEE Transactions on Mobile Computing, Vol. 4, No. 6, Nov./Dec. 2005. pp. 537–51 Current user movement prediction schemes rely largely on individual user’s mobility patterns. They exhibit high sensitivity to changes in the user’s behavior. Upon a change in a user’s mobility pattern or a fairly long pause in its mobility history, current mobility prediction schemes should go through a training phase before being able to provide an accurate prediction of the user’s future location. To cope with such an issue, the authors investigate the use of available environment and user available contextual knowledge to predict user mobility patterns. Referring to a spatial conceptual map along with a user’s personal information, DempsterShafer’s theory is used to extract different groups of candidate future locations of a mobile user. The Dempster rule of combination is then used on these groups to predict the most probable future location. The performance of the proposed mobility prediction is evaluated through computer simulations, and encouraging results are obtained. Given the importance of mobility prediction in handoff management, resource reservation, and QoS provisioning, the actual enhancements the proposed mobility prediction framework can indeed bring to this area of research can be an interesting topic for future investigations.

Shantidev Mohanty

Papers

NeXt generation/dynamic spectrum access/cognitive radio wireless networks: a survey

Scanning the literature