Dynamic spectrum access technologies based on Cognitive Radio(CR) is under intensive research carried out by the wireless communication society and is expected to solve the problem of spectrum scarcity.However,most en...Dynamic spectrum access technologies based on Cognitive Radio(CR) is under intensive research carried out by the wireless communication society and is expected to solve the problem of spectrum scarcity.However,most enabling technologies related to dynamic spectrum access are con-sidered individually.In this paper,we consider these key technologies jointly and introduce a new implementation scheme for a Dynamic Spectrum Access Network Based on Cognitive Radio(DSAN-BCR).We start with a flexible hardware platform for DSAN-BCR,as well as a flexible protocol structure that dominates the operation of DSAN-BCR.We then focus on the state of the art of key technologies such as spectrum sensing,spectrum resources management,dynamic spectrum access,and routing that are below the network layer in DSAN-BCR,as well as the development of technologies related to higher layers.Last but not the least,we analyze the challenges confronted by these men-tioned technologies in DSAN-BCR,and give the perspectives on the future development of these technologies.The DSAN-BCR introduced is expected to provide a system level guidance to alleviate the problem of spectrum scarcity.展开更多
A realistic population density distribution scenario in conjunction with the spatial dynamic spectrum allocation （DSA） is taken into account to mitigate the spectrum wastage in terms of extra guard bands. For the in...A realistic population density distribution scenario in conjunction with the spatial dynamic spectrum allocation （DSA） is taken into account to mitigate the spectrum wastage in terms of extra guard bands. For the insertion of the extra guard bands, an efficient strategy based on self-assessment is applied to each victim cell individually and independently. Consequently, it is no more required to spread the extra guard band over the whole DSA region. Simulation results StlOW an improvement of 3% -4% in percentage of satisfied users for Universal Mobile Telecommunications System （UMTS） network and 4%-5% for Digital Video Broadcasting Terrestrial （DVB-T） network.展开更多
In this paper,a genetic algorithm (GA) is investigated to deal with cell-by-cell dynamic spectrumallocation (DSA) in the heterogeneous scenario with temporal and spatial traffic demand changes,whichis also known as a ...In this paper,a genetic algorithm (GA) is investigated to deal with cell-by-cell dynamic spectrumallocation (DSA) in the heterogeneous scenario with temporal and spatial traffic demand changes,whichis also known as a difficult combinatorial optimization problem.A new two-dimensional chromosome encodingscheme is defined according to characteristics of the heterogeneous scenario,which prevents forminginvalid solutions during the genetic operation and enables much faster convergence.A novel randomcoloring gene generation function is presented which is the basic operation for initialization and mutationin the genetic algorithm.Simulative comparison demonstrates that the proposed GA-based cell-by-cellDSA outperforms the conventional contiguous DSA scheme both in terms of spectral efficiency gain andquality of service (QoS) satisfaction.展开更多
This paper presents an efficient dynamic spectrum allocation （DSA） scheme in a flexible spectrum licensing environment where multiple networks coexist and interfere with each other. In particular, an extension of vi...This paper presents an efficient dynamic spectrum allocation （DSA） scheme in a flexible spectrum licensing environment where multiple networks coexist and interfere with each other. In particular, an extension of virtual boundary concept in DSA is proposed, which is spectrally efficient than the previous virtual boundary concept applied to donor systems only. Here, the same technique is applied to both donor and rental systems so as to further reduce the occurrences where the insertion of guard bands is obligatory and as a result provides better spectral efficiency. The proposed extension improves the spectrum utilization without any compromise on interference and fairness issues.展开更多
With the deployment of more wireless applications, spectrum scarcity becomes an issue in many countries. Recent reports show that the reason for this spectrum shortage is the underutilization of some spectrum re-sourc...With the deployment of more wireless applications, spectrum scarcity becomes an issue in many countries. Recent reports show that the reason for this spectrum shortage is the underutilization of some spectrum re-sources. Fortunately, the emergence of open spectrum and dynamic spectrum assess (DSA) technology in cognitive radio networks relieves this problem. In this paper, we propose a novel DSA-driven cognitive MAC protocol to achieve highly efficient spectrum usage and QoS provisioning. In the proposed protocol, secondary users are divided into several non-overlapping groups, and all leftover channels are allocated among groups taking the groups’ bandwidth requirements into consideration. Moreover, the allocation of vacant channels can be adjusted dynamically when members join/leave groups or primary users return/leave the current network. Simulations show that the proposed MAC protocol greatly improves the quality of ser-vice for secondary users and maximizes the utilization ratio of spectrum resources.展开更多
在回顾了现有的开放式频谱系统中的动态频谱分配算法后,基于快速收敛和公平性两方面的性能因素并兼顾系统总带宽性能,提出了两种易于实现且具有良好收敛性能的启发式频谱动态分配算法——兼顾最大化系统总带宽的快速收敛算法(fast conve...在回顾了现有的开放式频谱系统中的动态频谱分配算法后,基于快速收敛和公平性两方面的性能因素并兼顾系统总带宽性能,提出了两种易于实现且具有良好收敛性能的启发式频谱动态分配算法——兼顾最大化系统总带宽的快速收敛算法(fast convergency algorithm with maximum bandwidth,简称FCMB)和兼顾最大化系统总带宽的启发式公平性分配算法(heuristic fairness algorithm with maximum bandwidth,简称HFWB).通过大量的仿真实验,就系统总带宽、公平性以及收敛性能3个方面,与现有的协调式最大化系统总带宽(collaboration max-sum-bandwidth,简称CMSB)算法、随机分布式算法(randomized distributed algorithm,简称RAND)以及以最大化系统总带宽为目标的理论最优(theoretical max-bandwidth optimal,简称OPTL)算法进行了比较,并针对主、次用户数目变化、系统中信道数目以及次用户干扰区域半径大小变化等不同系统参数情况下各种算法的性能进行了对比分析.仿真结果表明,在综合考虑系统总带宽的基础上,FCMB算法和HFWB算法在快速收敛和兼顾系统带宽的公平性能上分别表现突出,尤其是FCMB算法,其在收敛速度上远远优于其他算法(和与其在系统吞吐性能上表现相近的CMSB算法相比,在收敛性能上至少有300%的提高).展开更多
针对传统拍卖方法在动态频谱分配中的低效问题,本文提出了一种基于FADM(fast auction with multiple bands and multiple winners)算法的动态频谱分配方法.FADM算法将传统的多物品拍卖问题转化为整数型0/1背包问题,从而可用动态规划寻...针对传统拍卖方法在动态频谱分配中的低效问题,本文提出了一种基于FADM(fast auction with multiple bands and multiple winners)算法的动态频谱分配方法.FADM算法将传统的多物品拍卖问题转化为整数型0/1背包问题,从而可用动态规划寻求最佳的出清向量;新算法采用了保留价格和差异定价抑制共谋,且根据供求关系动态调整保留价格和竞标价格,兼顾了频谱分配的经济效益和社会效益.性能分析和计算机仿真结果表明,FADM算法可以使频谱有效利用率逼近实际需求率,同时尽可能提高分配收益.展开更多
文摘Dynamic spectrum access technologies based on Cognitive Radio(CR) is under intensive research carried out by the wireless communication society and is expected to solve the problem of spectrum scarcity.However,most enabling technologies related to dynamic spectrum access are con-sidered individually.In this paper,we consider these key technologies jointly and introduce a new implementation scheme for a Dynamic Spectrum Access Network Based on Cognitive Radio(DSAN-BCR).We start with a flexible hardware platform for DSAN-BCR,as well as a flexible protocol structure that dominates the operation of DSAN-BCR.We then focus on the state of the art of key technologies such as spectrum sensing,spectrum resources management,dynamic spectrum access,and routing that are below the network layer in DSAN-BCR,as well as the development of technologies related to higher layers.Last but not the least,we analyze the challenges confronted by these men-tioned technologies in DSAN-BCR,and give the perspectives on the future development of these technologies.The DSAN-BCR introduced is expected to provide a system level guidance to alleviate the problem of spectrum scarcity.
基金The National High-Tech Research and Development Program of China ( No.2005AA123950)the National Science Foundation of China (No.90604035)
文摘A realistic population density distribution scenario in conjunction with the spatial dynamic spectrum allocation （DSA） is taken into account to mitigate the spectrum wastage in terms of extra guard bands. For the insertion of the extra guard bands, an efficient strategy based on self-assessment is applied to each victim cell individually and independently. Consequently, it is no more required to spread the extra guard band over the whole DSA region. Simulation results StlOW an improvement of 3% -4% in percentage of satisfied users for Universal Mobile Telecommunications System （UMTS） network and 4%-5% for Digital Video Broadcasting Terrestrial （DVB-T） network.
基金Supported by the National Basic Research Program of China (No. 2007CB310606)
文摘In this paper,a genetic algorithm (GA) is investigated to deal with cell-by-cell dynamic spectrumallocation (DSA) in the heterogeneous scenario with temporal and spatial traffic demand changes,whichis also known as a difficult combinatorial optimization problem.A new two-dimensional chromosome encodingscheme is defined according to characteristics of the heterogeneous scenario,which prevents forminginvalid solutions during the genetic operation and enables much faster convergence.A novel randomcoloring gene generation function is presented which is the basic operation for initialization and mutationin the genetic algorithm.Simulative comparison demonstrates that the proposed GA-based cell-by-cellDSA outperforms the conventional contiguous DSA scheme both in terms of spectral efficiency gain andquality of service (QoS) satisfaction.
基金This work was supported in part by the National Nature Science Foundation of China (NSFC) under Grant No. 90604035the 863 high-tech R&D program of China under Grant No. 2005AA123950.
文摘This paper presents an efficient dynamic spectrum allocation （DSA） scheme in a flexible spectrum licensing environment where multiple networks coexist and interfere with each other. In particular, an extension of virtual boundary concept in DSA is proposed, which is spectrally efficient than the previous virtual boundary concept applied to donor systems only. Here, the same technique is applied to both donor and rental systems so as to further reduce the occurrences where the insertion of guard bands is obligatory and as a result provides better spectral efficiency. The proposed extension improves the spectrum utilization without any compromise on interference and fairness issues.
文摘With the deployment of more wireless applications, spectrum scarcity becomes an issue in many countries. Recent reports show that the reason for this spectrum shortage is the underutilization of some spectrum re-sources. Fortunately, the emergence of open spectrum and dynamic spectrum assess (DSA) technology in cognitive radio networks relieves this problem. In this paper, we propose a novel DSA-driven cognitive MAC protocol to achieve highly efficient spectrum usage and QoS provisioning. In the proposed protocol, secondary users are divided into several non-overlapping groups, and all leftover channels are allocated among groups taking the groups’ bandwidth requirements into consideration. Moreover, the allocation of vacant channels can be adjusted dynamically when members join/leave groups or primary users return/leave the current network. Simulations show that the proposed MAC protocol greatly improves the quality of ser-vice for secondary users and maximizes the utilization ratio of spectrum resources.
基金Supported by the National Basic Research Program of China under Grant No.2003CB314806(国家重点基础研究发展计划(973)) the National High-Tech Research and Development Plan of China under Grant No.2007AA12Z321(国家高技术研究发展计划(863))+2 种基金National Natural Science Foundation of China under Grant Nos.60603060 60472067 90604019 (国家自然科学基金)
文摘在回顾了现有的开放式频谱系统中的动态频谱分配算法后,基于快速收敛和公平性两方面的性能因素并兼顾系统总带宽性能,提出了两种易于实现且具有良好收敛性能的启发式频谱动态分配算法——兼顾最大化系统总带宽的快速收敛算法(fast convergency algorithm with maximum bandwidth,简称FCMB)和兼顾最大化系统总带宽的启发式公平性分配算法(heuristic fairness algorithm with maximum bandwidth,简称HFWB).通过大量的仿真实验,就系统总带宽、公平性以及收敛性能3个方面,与现有的协调式最大化系统总带宽(collaboration max-sum-bandwidth,简称CMSB)算法、随机分布式算法(randomized distributed algorithm,简称RAND)以及以最大化系统总带宽为目标的理论最优(theoretical max-bandwidth optimal,简称OPTL)算法进行了比较,并针对主、次用户数目变化、系统中信道数目以及次用户干扰区域半径大小变化等不同系统参数情况下各种算法的性能进行了对比分析.仿真结果表明,在综合考虑系统总带宽的基础上,FCMB算法和HFWB算法在快速收敛和兼顾系统带宽的公平性能上分别表现突出,尤其是FCMB算法,其在收敛速度上远远优于其他算法(和与其在系统吞吐性能上表现相近的CMSB算法相比,在收敛性能上至少有300%的提高).
文摘针对传统拍卖方法在动态频谱分配中的低效问题,本文提出了一种基于FADM(fast auction with multiple bands and multiple winners)算法的动态频谱分配方法.FADM算法将传统的多物品拍卖问题转化为整数型0/1背包问题,从而可用动态规划寻求最佳的出清向量;新算法采用了保留价格和差异定价抑制共谋,且根据供求关系动态调整保留价格和竞标价格,兼顾了频谱分配的经济效益和社会效益.性能分析和计算机仿真结果表明,FADM算法可以使频谱有效利用率逼近实际需求率,同时尽可能提高分配收益.
