This paper investigates channel allocation and power control schemes in OFDM-based multi-hop cognitive radio networks.The color-sensitive graph coloring(CSGC) model is viewed as an efficient solution to the spectrum a...This paper investigates channel allocation and power control schemes in OFDM-based multi-hop cognitive radio networks.The color-sensitive graph coloring(CSGC) model is viewed as an efficient solution to the spectrum assignment problem.The model is extended to combine with the power control strategy to avoid interference among secondary users and adapt dynamic topology.The optimization problem is formulated encompassing the channel allocation and power control with the interference constrained below a tolerable limit.Meanwhile,the proposed resource allocation scheme takes the fairness of secondary users into account in obtaining the solution of optimization.Numerical results show that the proposed strategy outperforms the existing spectrum assignment algorithms on the performance of both the network throughput and minimum route bandwidth of all routes,as well as the number of connected multi-hop routes which implies the fairness among secondary users.展开更多
We investigate the bandwidth allocation and power control schemes in orthogonal frequency division multiplexing (OFDM) based multi-hop cognitive radio networks,and the color-sensitive graph coloring (CSGC) model is vi...We investigate the bandwidth allocation and power control schemes in orthogonal frequency division multiplexing (OFDM) based multi-hop cognitive radio networks,and the color-sensitive graph coloring (CSGC) model is viewed as an efficient solution to the spectrum assignment problem. We extend the model by taking into account the power control strategy to avoid interference among secondary users and adapt dynamic topology. We formulate the optimization problem encompassing the channel allocation,power control with the interference constrained below a tolerable limit. The optimization objective with two different optimization strategies focuses on the routes rather than the links as in traditional approaches. A heuristic solution to this nondeterministic polynomial (NP)-hard problem is presented,which performs iterative channel allocation according to the lowest transmission power that guarantees the link connection and makes channel reuse as much as possible,and then the transmission power of each link is maximized to improve the channel capacity by gradually adding power level from the lowest transmission power until all co-channel links cannot satisfy the interference constraints. Numerical results show that our proposed strategies outperform the existing spectrum assignment algorithms in the performance of both the total network bandwidth and minimum route bandwidth of all routes,meanwhile,saving the transmission power.展开更多
A joint channel selection and power control scheme is developed for video streaming in device-to-device （D2D） communications based cognitive radio networks. In particular, physical queue and virtual queue models by ...A joint channel selection and power control scheme is developed for video streaming in device-to-device （D2D） communications based cognitive radio networks. In particular, physical queue and virtual queue models by applying ＇M/G/1 queue＇ and ＇M/G/1 queue with vacations＇ theories are built up, respectively, to evaluate the delays experienced by various video traffics. Such delays play a vital role in calculating the packet loss rate for video streaming, which reflects the video distortion. Based on the distortion model, a video distortion minimization problem is formulated, subject to the rate constraint, maximum power constraint, primary users＇ tolerant interference constraint, and secondary users＇ minimum data rate requirement constraint. The optimization problem turns out to be a mixed integer nonlinear programming （MINLP） , which is generally nondeterministic in polynomial time. A Lagrangian dual method is thus employed to reformulate the video distortion minimization problem, based on which the sub-gradient algorithm is used to determine a relaxed solution. Thereafter, applying the iterative user removal yields the optimal joint channel selection and power control solution to the original MINLP problem. Extensive simulations validate our proposed scheme and demonstrate that it significantly increases the peak signal- to-noise ratio （PSNR） compared with the existing schemes.展开更多
In this paper,a novel WLAN system,Cognitive WLAN over Fiber (CWLANoF),is introduced in the first place.Moreover,when CWLANoF has more channels than STAs,a new channel allocation scheme is proposed using the Hungarian ...In this paper,a novel WLAN system,Cognitive WLAN over Fiber (CWLANoF),is introduced in the first place.Moreover,when CWLANoF has more channels than STAs,a new channel allocation scheme is proposed using the Hungarian algorithm,which is demonstrated to be the optimal one.Furthermore,when CWLANoF has fewer channels than STAs,it is possible for more than one STA to share the same channel simultaneously based on the new features of CWLANoF.And the power control scheme is proposed for this kind of sharing,considering efficiency and fairness.Finally,extensive simulation results illustrate the significant performance improvement of the proposed channel allocation scheme and power control scheme.展开更多
基金Supported by the National Natural Science Foundation of China(No.61461006)the Guangxi Province Natural Science Foundation(No.2013GXNSFBA19271)
文摘This paper investigates channel allocation and power control schemes in OFDM-based multi-hop cognitive radio networks.The color-sensitive graph coloring(CSGC) model is viewed as an efficient solution to the spectrum assignment problem.The model is extended to combine with the power control strategy to avoid interference among secondary users and adapt dynamic topology.The optimization problem is formulated encompassing the channel allocation and power control with the interference constrained below a tolerable limit.Meanwhile,the proposed resource allocation scheme takes the fairness of secondary users into account in obtaining the solution of optimization.Numerical results show that the proposed strategy outperforms the existing spectrum assignment algorithms on the performance of both the network throughput and minimum route bandwidth of all routes,as well as the number of connected multi-hop routes which implies the fairness among secondary users.
基金Project supported by the National Natural Science Foundation of China (Nos. 60496315, 60702039, and 60802009)the National High-Tech Research and Development Program (863) of China (Nos. 2006AA0Z277 and 2008AA01Z211)+1 种基金the International Science and Technology Cooperation Programme of China (No. 2008DFA11630)the Natural Science Foundation of Hubei Province, China (No. 2008CDB325)
文摘We investigate the bandwidth allocation and power control schemes in orthogonal frequency division multiplexing (OFDM) based multi-hop cognitive radio networks,and the color-sensitive graph coloring (CSGC) model is viewed as an efficient solution to the spectrum assignment problem. We extend the model by taking into account the power control strategy to avoid interference among secondary users and adapt dynamic topology. We formulate the optimization problem encompassing the channel allocation,power control with the interference constrained below a tolerable limit. The optimization objective with two different optimization strategies focuses on the routes rather than the links as in traditional approaches. A heuristic solution to this nondeterministic polynomial (NP)-hard problem is presented,which performs iterative channel allocation according to the lowest transmission power that guarantees the link connection and makes channel reuse as much as possible,and then the transmission power of each link is maximized to improve the channel capacity by gradually adding power level from the lowest transmission power until all co-channel links cannot satisfy the interference constraints. Numerical results show that our proposed strategies outperform the existing spectrum assignment algorithms in the performance of both the total network bandwidth and minimum route bandwidth of all routes,meanwhile,saving the transmission power.
基金supported by the National Natural Science Foundation of China ( 61371127,61671347)the 111 Project of China ( B08038 )+1 种基金the Fundamental Research Funds for the Central Universities ( 7214603701 )the Key Technology R&D Program of Henan Province ( 142102210572)
文摘A joint channel selection and power control scheme is developed for video streaming in device-to-device （D2D） communications based cognitive radio networks. In particular, physical queue and virtual queue models by applying ＇M/G/1 queue＇ and ＇M/G/1 queue with vacations＇ theories are built up, respectively, to evaluate the delays experienced by various video traffics. Such delays play a vital role in calculating the packet loss rate for video streaming, which reflects the video distortion. Based on the distortion model, a video distortion minimization problem is formulated, subject to the rate constraint, maximum power constraint, primary users＇ tolerant interference constraint, and secondary users＇ minimum data rate requirement constraint. The optimization problem turns out to be a mixed integer nonlinear programming （MINLP） , which is generally nondeterministic in polynomial time. A Lagrangian dual method is thus employed to reformulate the video distortion minimization problem, based on which the sub-gradient algorithm is used to determine a relaxed solution. Thereafter, applying the iterative user removal yields the optimal joint channel selection and power control solution to the original MINLP problem. Extensive simulations validate our proposed scheme and demonstrate that it significantly increases the peak signal- to-noise ratio （PSNR） compared with the existing schemes.
基金Sponsored by the National Natural Science Foundation of China (Grant No.60832009 )Beijing Municipal Natural Science Foundation (Grant No.4102044)National Youth Science Foundation (Grant No.61001115)
文摘In this paper,a novel WLAN system,Cognitive WLAN over Fiber (CWLANoF),is introduced in the first place.Moreover,when CWLANoF has more channels than STAs,a new channel allocation scheme is proposed using the Hungarian algorithm,which is demonstrated to be the optimal one.Furthermore,when CWLANoF has fewer channels than STAs,it is possible for more than one STA to share the same channel simultaneously based on the new features of CWLANoF.And the power control scheme is proposed for this kind of sharing,considering efficiency and fairness.Finally,extensive simulation results illustrate the significant performance improvement of the proposed channel allocation scheme and power control scheme.
