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Search Results: 1 - 10 of 7804 matches for " spectrum sensing "
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Detection Proposal Schemes for Spectrum Sensing in Cognitive Radio  [PDF]
Nawaf Hadhal Kamil, Xiuhua Yuan
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.24048
Abstract: The most important components of the cognitive radio concept is its ability to measure, sense and learn. One also should be aware of the parameters related to the radio channel characteristics and the availability of spectrum and power. In cognitive radio technology, primary users can be defined as the users who have the highest priority on the usage of a specific part of the spectrum. Secondary users, have lower priority, and should not cause any interference to the primary users when using the technology. Therefore, the secondary users need to have certain cognitive radio capabilities, such as sensing the spectrum to check whether it is being used by primary user or not, and changing the radio parameters to exploit the unused part of the spectrum. In this paper we proposed a new approach for spectrum sensing, In the first approach the primary signal is known so we use the code value with match filter to detect the primary user, on the other hand, when the primary user signal is unknown we proposed a new strategy for energy detection in both non-cooperation and cooperation schemes. Then we will prove by simulation results that the new approach is better than the conventional energy detection.
Performance Evaluation of Spectrum Detection in Cognitive Radio Network  [PDF]
Shubhangi Mahamuni, Vivekanand Mishra
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2014, DOI: 10.4236/ijcns.2014.711049
Abstract: In mobility management, detection of spectrum hole plays very important role for doing spectrum handoff mechanism. Operation of the cognitive radio depends on the spectrum sensing which is the most important task in case of cognitive radio network. Detection of spectrum holes (underutilized sub-bands of the radio spectrum) estimates average power, throughput and utilized time for each spectrum hole. But in case of reactive spectrum handoff mechanism, spectrum handoff delay becomes tedious task. So in order to make spectrum handoff mechanism efficient our scheme proposed spectrum handoff mechanism with negligible spectrum handoff delay. In this paper we had real time experimental setup with the spectrum handoff mechanism. We investigate algorithm for spectrum handoff mechanism which strongly minimizes spectrum handoff delay of cognitive radio network using spectrum detection method for sensing spectrum holes.
A Self-Optimization of the Dynamic Resource Management Based on the Cognitive Radio  [PDF]
Jamal Raiyn
Wireless Engineering and Technology (WET) , 2011, DOI: 10.4236/wet.2011.22012
Abstract: This paper describes a novel self-optimized approach for resource management based on the cognitive radio in the cellular networks. The cognitive radio techniques offer several features like autonomy, sensing and negotiation. The use of cognitive radio approach gives greater autonomy to the base stations in the cellular networks. This autonomy allows an increase in flexibility to deal with new situations in the traffic load. The negotiation strategy is used to avoid conflicts in the resource allocation. The goal of the cognitive radio scheme is to achieve a high degree of resource usage and a low rate of call blocking in the cellular systems.
A Spectrum Sensing Framework for UWB-Cognitive Network  [PDF]
Deah J. Kadhim, Saba Q. Jobbar
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.28077
Abstract: Due to that the Ultra Wide Band (UWB) technology has some attractive features like robustness to multipath fading, high data rate, low cost and low power consumption, it is widely use to implement cognitive radio network. Intuitively, one of the most important tasks required for cognitive network is the spectrum sensing. A framework for implementing spectrum sensing for UWB-Cognitive Network will be presented in this paper. Since the information about primary licensed users are known to the cognitive radios then the best spectrum sensing scheme for UWB-cognitive network is the matched filter detection scheme. Simulation results verified and demonstrated the using of matched filter spectrum sensing in cognitive radio network with UWB and proved that the bit error rate for this detection scheme can be considered acceptable.
Optimization of Threshold for Energy Based Spectrum Sensing Using Differential Evolution  [PDF]
K. Aravind Narayanan, P. Arun Shivaram, M. Maheshkumar, Santhoshkumar. K, L. Sathiesh Kumar, K.A Narayanankutty
Wireless Engineering and Technology (WET) , 2011, DOI: 10.4236/wet.2011.23019
Abstract: Interference threshold based on energy setting in cognitive radios is a non-convex optimization problem [4]. The convergence of optimization techniques like Genetic algorithm (GA) takes several iterations to fix this threshold. Here, an attempt made to use Differential evolution (DE) method for optimization after formulating the objective functions. The advantages with this method were three fold over GA. They were, a. A reduced number of iterations, b. Marginal improvement and consistency of throughput and c. Localization of the best solution. The comparative results are presented and discussed.
Asymptotic Value of the Probability That the First Order Statistic Is from Null Hypothesis  [PDF]
Iickho Song, Seungwon Lee, So Ryoung Park, Seokho Yoon
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.412231
Abstract:

When every element of a random vector X =(X1,X2,...,Xn) assumes the cumulative distribution function F0 and F1 with probability p and 1 - p, respectively, we have shown that the probability S0 that the first order statistic of X is originally under F0 can be expressed as \"\". We have also shown that \"\", where \"\" and \"\"  with \"\" the support of (x) . Applications and implications of the results are discussed in the performance of wideband spectrum sensing schemes.

Artificial Intelligence Based Model for Channel Status Prediction: A New Spectrum Sensing Technique for Cognitive Radio  [PDF]
Sandhya Pattanayak, Palanaindavar Venkateswaran, Rabindranath Nandi
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2013, DOI: 10.4236/ijcns.2013.63017
Abstract:

The recent phenomena of tremendous growth in wireless communication application urge increasing need of radio spectrum, albeit it being a precious but natural resource. The recent technology under development to overview the situation is the concept of Cognitive Radio (CR). Recently the Artificial Intelligence (AI) tools are being considered for the topic. AI is the core of the cognitive engine that examines the external and internal environment parameters that leads to some postulations for QoS improvement. In this article, we propose a new Artificial Neural Network (ANN) model for detection of a spectrum hole. The model is trained with some pertinent features over a channel like SNR, channel capacity, bandwidth efficiency etc. The channel capacity status could be identified in a quantized index form . Some simulation results are presented.

Performance Analysis of Suboptimal Spectrum Sensing Algorithm in Cognitive Networks
American Journal of Signal Processing , 2011, DOI: 10.5923/j.ajsp.20110101.03
Abstract: Recently, both optimal and suboptimal spectrum sensing approaches have attracted extensive attention in wireless communications field. Thanks to opportunistic spectrum access schemes, different cognitive users can cooperatively search for and exploit instantaneous spectrum availability. In this paper, we address the analysis of spectrum sensing in opportunistic spectrum access models and then determine throughput of the cognitive radio system. Our goal in all designs is reach optimal access policy for each channel with the high cooperative sensing performances.
A Cognitive Radio Receiver Supporting Wide-Band Sensing  [PDF]
Volker BLASCHKE, Tobias RENK, Friedrich K. JONDRAL
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.13018
Abstract: The specification of IEEE 802.22 defines the world-wide first cognitive radio (CR) standard. Within a range of 40 MHz to 910 MHz CR systems are allowed to allocate spectrum besides the currently established radio services like radio and TV broadcasting. In order to fulfill the regulative guidelines of interference limita-tions, a capable spectral sensing and user detection has to be provided. Due to the wide frequency range specified in IEEE 802.22 and the high dynamic range of signals allocated in this band there are high de-mands on the CR receiver’s front-end. Especially the performance requirements on analog-to-digital con-verters increase significantly compared to current wireless systems. Based on measurements taken in this frequency range requirements to CR’s ADCs are figured out. Furthermore, the measurement results are ana-lyzed regarding expectable allocation scenarios and their impacts to spectral sensing. Derived from this re-sults and a comparison of general spectral sensing mechanisms an approach for a CR receiver supporting wide-band sensing is presented. Considering the apriori information resulting from scenario analysis and including adapted information processing in the terminal the ADC’s performance requirements can be re-duced.
Secure Cooperative Spectrum Sensing based on the Distance between Bodies of Evidence  [PDF]
Yi Wang, Yanjun Hu, Xiwen Tang, Yingguan Wang
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.51008
Abstract: In cognitive radio (CR) networks, unlicensed secondary users need to conduct spectrum sensing to gain access to a licensed spectrum band. And cooperation among CR users will solve the problems caused by multipath fading and shadowing. In this paper, we propose a multi-threshold method at local nodes to cope with noises of great uncertainty. Functions of distance between bodies of evidence are used at fusion centre to make synthetic judgment. To guarantee security which is an essential component for basic network functions, we will take selfish nodes into account which try to occupy channels exclusively. The proposed technique has shown better performance than conventional algorithms without increase the system overhead.
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