Cognitive network

About: Cognitive network is a research topic. Over the lifetime, 4213 publications have been published within this topic receiving 107093 citations.

Cognitive Multi-Radio Mesh Networks on ISM bands: A cross-layer architecture

Abstract: A wireless mesh network (WMN) has been popularly researched as a wireless backbone for Internet access with off-the-shelf and inexpensive equipments. Nowadays, several applications like contents sharing, multicast video streaming, vehicular networks encourage to build mesh networks in urban areas. However, the deployment of WMNs in unlicensed bands of dense urban areas imposes many challenges. While previous research has mostly focused on optimal channel allocation under inter or intra-flow interferences within mesh nodes, the practical deployment of WMNs also requires to consider the interference caused by external entities such as residential access points that do not belong to the WMN. To address this issue, we propose Urban-X which is a first attempt towards a new architecture for Multi-Radio Cognitive Mesh Networks. Based on a cross-layer scheme, we develop novel routing and forwarding schemes reflecting the residential traffic state of external users. Through an extensive simulation analysis using the ns-2 simulator, we demonstrate the feasibility of our routing scheme and we show its robustness to the variations of channel environment and external traffics.

Applying cognitive radio concepts to HF communications

Abstract: The concept of cognitive radio, originally proposed in 1998, has since then inspired growing interest and research activity. While the proper definition of the term "cognitive radio" remains debated, the concepts commonly offered as examples of cognitive radio all seem to involve ways in which a radio system can sense relevant features of its environment such as location, spectrum utilization, and spectrum availability, and intelligently adapt its behaviour and resource usage in light of regulatory constraints, equipment state, and other factors, so as to best meet the communication needs of the user. While the automatic link establishment techniques widely used in HF radio systems are frequently offered as an example of an early, limited form of cognitive radio, most of the research attention in this area has been given to communications bands well above the 30 MHz upper limit of HF. In this paper, we first provide a concise overview of the variety of techniques that have been proposed as applications of the cognitive radio concept, and consider the applicability of these techniques to HF communications, in light of the distinctive characteristics of the HF communications medium and its typical uses. We then consider whether there might be distinctive cognitive techniques having promise to improve the effectiveness of HF communications, in spite of their having received little or no attention in other domains, and discuss potential challenges and critical success factors impacting the prospects for successful application of cognitive techniques to HF communications.

A Survey of Cooperative Games for Cognitive Radio Networks

Abstract: Cooperative cognitive radio networks are new cognitive radio paradigm. Cooperative communication approaches, such as cooperative spectrum sensing and cooperative spectrum sharing, are playing key roles in the development of cognitive radio networks. To achieve the high performance, a cooperative cognitive communication framework is often used to model various cooperative spectrum sensing or sharing scenarios. However, its implementation faces numerous challenges due to the complexity of mobility and traffic models, the needs of dynamic spectrum access, the heterogeneous requirements from different users, and the distributed structure of the network. Fortunately, cooperative game theory can be used to formulate and model the interactions among licensed and unlicensed users for spectrum sensing and spectrum sharing to efficiently allocate spectrum resource in the highly dynamic and distributed radio environment. In this paper, we first present the cooperative communication technologies and describe their existing challenges, then introduce different game solutions, after that, we discuss several cooperative game strategies, and analyze the associated their applications in cognitive radio networks, at final, some open directions for future research on economic strategies in cooperative communication in cognitive radio networks are proposed.

Comparison of reliability, delay and complexity for standalone cognitive radio spectrum sensing schemes

Abstract: The ability to reliably and autonomously identify unused frequency bands plays an extremely important role in cognitive radio networks. Relying on the spectrum sensing, ongoing licensed operation must not be compromised and the secondary spectrum usage efficiency should be maintained. Thus, it is critical to ensure that the confidence level of the estimated signal status satisfies the primary user's requirement, while keeping the delay and computational complexity to a minimum. This study provides a comprehensive comparison in terms of performance, reliability and complexity of standalone sensing schemes for various cognitive radio application areas. The authors first give some new results on reliability performance, and then evaluate the sensing time required to achieve the target performance. Finally, the authors compare the computational complexity of various sensing approaches by calculating the number of arithmetic operations required by each approach.