Fuzzy sets, decision making and expert systems
Fuzzy sets, decision making and expert systems
Performance Evaluation of Modified IEEE 802.11 MAC for Multi-Channel Multi-Hop Ad Hoc Network
AINA '03 Proceedings of the 17th International Conference on Advanced Information Networking and Applications
ISPAN '00 Proceedings of the 2000 International Symposium on Parallel Architectures, Algorithms and Networks
Proceedings of the 5th ACM international symposium on Mobile ad hoc networking and computing
NeXt generation/dynamic spectrum access/cognitive radio wireless networks: a survey
Computer Networks: The International Journal of Computer and Telecommunications Networking
White space networking with wi-fi like connectivity
Proceedings of the ACM SIGCOMM 2009 conference on Data communication
Cognitive radio: brain-empowered wireless communications
IEEE Journal on Selected Areas in Communications
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To increase possible data transmission rate and to provide non-primary user's desired throughput in short-range communications, in this paper we propose new cognitive radio (CR) network architecture with the coexistence with the legacy IEEE 802.11 WLAN. The legacy WLAN ISM band channel is mostly used for common control channel for cognitive operation on the licensed bands to manage CR devices when they join the network and to announce the utilization of the licensed band or primary system appearance on the current used channels. The proposed CR-WLAN MAC protocol is designed to accommodate new CR related features in the proposed network architecture and it has backward compatibility to the legacy WLAN system: (1) Network entry procedure is modified to inform CR users the current licensed band status and to manage CR user group separately by AP; (2) During the operation, two types of CR beacon multicasting mechanisms are proposed, CR beacons help CR users to decide its service change or spectrum handover and to immediately evacuate from the current used channel when primary signal is detected, (3) When the CR user need to change the serving CR AP, not only the beacon frame body of neighbor APs but also the licensed and unlicensed band status is delivered to CR node to search the target CR-WLAN AP fast and (4) A new type of hidden node problem is introduced that focuses on possible signal collisions between incumbent devices and cognitive radio CR-WLAN devices, and a simple and efficient sensing information exchange mechanism between neighbor APs is proposed. The simulation results show that the proposed CR system can provide reliable protection to primary systems, as well as efficient utilization of given licensed spectrum resources, in which the network throughput can be greatly enhanced.