Results 1 - 10 of 3,708

NeXt generation/dynamic spectrum access/cognitive Radio Wireless Networks: A Survey

by Ian F. Akyildiz, Won-Yeol Lee, Mehmet C. Vuran, Shantidev Mohanty - COMPUTER NETWORKS JOURNAL (ELSEVIER , 2006
"... Today's wireless networks are characterized by a fixed spectrum assignment policy. However, a large portion of the assigned spectrum is used sporadically and geographical variations in the utilization of assigned spectrum ranges from 15% to 85% with a high variance in time. The limited availabl ..."
Abstract - Cited by 746 (15 self) - Add to MetaCart
available spectrum and the ine#ciency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. This new networking paradigm is referred to as NeXt Generation (xG) Networks as well as Dynamic Spectrum Access (DSA) and cognitive radio networks

Recent and Emerging Topics in Wireless Industrial Communications: A Selection

by Andreas Willig , 2007
"... In this paper we discuss a selection of promising and interesting research areas in the design of protocols and systemsforwirelessindustrialcommunications.Wehaveselected topicsthathaveeitheremergedashottopicsintheindustrial communicationscommunityinthelastfewyears(likewireless sensornetworks),orwhi ..."
Abstract - Cited by 96 (1 self) - Add to MetaCart
),orwhichcouldbeworthwhileresearchtopicsin thenextfewyears(forexamplecooperativediversitytechniques for error control, cognitive radio/opportunistic spectrum access for mitigation of external interferences).

Cognitive Radio: Brain-Empowered Wireless Communications

by Simon Haykin , 2005
"... Cognitive radio is viewed as a novel approach for improving the utilization of a precious natural resource: the radio electromagnetic spectrum. The cognitive radio, built on a software-defined radio, is defined as an intelligent wireless communication system that is aware of its environment and use ..."
Abstract - Cited by 1541 (4 self) - Add to MetaCart
Cognitive radio is viewed as a novel approach for improving the utilization of a precious natural resource: the radio electromagnetic spectrum. The cognitive radio, built on a software-defined radio, is defined as an intelligent wireless communication system that is aware of its environment

Implementation issues in spectrum sensing for cognitive radios

by Danijela Cabric, Shridhar Mubaraq Mishra, Robert W. Brodersen - in Proc. the 38th. Asilomar Conference on Signals, Systems, and Computers , 2004
"... Abstract- There are new system implementation challenges involved in the design of cognitive radios, which have both the ability to sense the spectral environment and the flexibility to adapt transmission parameters to maximize system capacity while co-existing with legacy wireless networks. The cri ..."
Abstract - Cited by 440 (7 self) - Add to MetaCart
Abstract- There are new system implementation challenges involved in the design of cognitive radios, which have both the ability to sense the spectral environment and the flexibility to adapt transmission parameters to maximize system capacity while co-existing with legacy wireless networks

Ultra-wide bandwidth time-hopping spread spectrum impulse radio for wireless access communications

by Moe Z. Win, Robert A. Scholtz - IEEE TRANS. COMMUN , 2000
"... Attractive features of time-hopping spread-spectrum multiple-access systems employing impulse signal technology are outlined, and emerging design issues are described. Performance of such communications systems in terms of achievable transmission rate and multiple-access capability are estimated fo ..."
Abstract - Cited by 456 (16 self) - Add to MetaCart
Attractive features of time-hopping spread-spectrum multiple-access systems employing impulse signal technology are outlined, and emerging design issues are described. Performance of such communications systems in terms of achievable transmission rate and multiple-access capability are estimated

unknown title

by unknown authors
"... Abstract—This paper deals with the learning and decision making issue for cognitive radio (CR). Two reinforcement-learning algorithms proposed in the literature are compared for opportunistic spectrum access (OSA): Upper Confidence Bound (UCB) algorithm and Weight Driven (WD) algorithm. This paper a ..."
Abstract - Add to MetaCart
Abstract—This paper deals with the learning and decision making issue for cognitive radio (CR). Two reinforcement-learning algorithms proposed in the literature are compared for opportunistic spectrum access (OSA): Upper Confidence Bound (UCB) algorithm and Weight Driven (WD) algorithm. This paper

Multi-Channel Opportunistic Spectrum Access in Unslotted Primary Systems with Unknown Models

by Pouya Tehrani, Qing Zhao, Lang Tong
"... Abstract—Multi-channel opportunistic spectrum access in unslotted primary systems is considered. The primary occupancy of each channel is modeled as a general on-off renewal process. The distributions of the busy and idle times and the utilization factors of all channels are unknown to the secondary ..."
Abstract - Cited by 4 (2 self) - Add to MetaCart
not directly reflecting throughput, preserves the ranking of the channels in terms of throughput. Index Terms—Cognitive radio, opportunistic spectrum access, multi-armed bandit, online learning, renewal process. I.

Opportunistic Spectrum Access for

by Alexander W. Min, Er W. Min, Kyu-han Kim, Jatinder Pal Singh, Kang G. Shin , 2016
"... Opportunistic spectrum access for mobile cognitive radios ..."
Abstract - Add to MetaCart
Opportunistic spectrum access for mobile cognitive radios

Opportunistic Spectrum Access for Energy-constrained Cognitive Radios

by Anh Tuan Hoang, Ying-chang Liang, David Tung, Chong Wong, Yonghong Zeng, Rui Zhang
"... This paper considers a scenario in which a secondary user makes opportunistic use of a channel allocated to some primary network. The primary network operates in a time-slotted manner and switches between idle and active states according to a stationary Markovian process. At the beginning of each ti ..."
Abstract - Cited by 31 (1 self) - Add to MetaCart
idle or carry out sensing, and if so, for how long, to maximize the expected net reward. We formulate this problem as a partially observable Markov decision process (POMDP) and prove several structural properties of the optimal spectrum sensing/accessing policies. Based on these properties, heuristic

Cooperative sensing among cognitive radios

by Shridhar Mubaraq Mishra, Anant Sahai, Robert W. Brodersen - In Proc. of the IEEE International Conference on Communications (ICC , 2006
"... Abstract — Cognitive Radios have been advanced as a technology for the opportunistic use of under-utilized spectrum since they are able to sense the spectrum and use frequency bands if no Primary user is detected. However, the required sensitivity is very demanding since any individual Radio might f ..."
Abstract - Cited by 289 (15 self) - Add to MetaCart
Abstract — Cognitive Radios have been advanced as a technology for the opportunistic use of under-utilized spectrum since they are able to sense the spectrum and use frequency bands if no Primary user is detected. However, the required sensitivity is very demanding since any individual Radio might
Results 1 - 10 of 3,708