Although small cell offloading technology can alleviate the congestion in macrocell, aggressively offloading data traffic from macrocell to small cell can also degrade the performance of small cell due to the heavy lo...Although small cell offloading technology can alleviate the congestion in macrocell, aggressively offloading data traffic from macrocell to small cell can also degrade the performance of small cell due to the heavy load. Because of collision and backoff, the degradation is significant especially in network with contention-based channel access, and finally decreases throughput of the whole network. To find an optimal fraction of traffic to be offloaded in heterogeneous network, we combine Markov chain with the Poisson point process model to analyze contention-based throughput in irregularly deployment networks. Then we derive the close-form solution of the throughput and find that it is a function of the transmit power and density of base stations.Based on this, we propose the load-aware offloading strategies via power control and base station density adjustment. The numerical results verify our analysis and show a great performance gain compared with non-load-aware offloading.展开更多
本文研究了在毫微微蜂窝网络(femtocell network,FN)中,协同双小区系统的非正交多址接入(non-orthogonal multiple access,NOMA)与无线携能通信(simultaneous wireless information and power transfer,SWIPT)下行协作通信的中断性能,...本文研究了在毫微微蜂窝网络(femtocell network,FN)中,协同双小区系统的非正交多址接入(non-orthogonal multiple access,NOMA)与无线携能通信(simultaneous wireless information and power transfer,SWIPT)下行协作通信的中断性能,提出了一种边缘用户在邻基站及源基站随机中心用户共同协作的下行接入方案。所提方案共分为两个时隙:第一时隙内由两基站向所有用户广播叠加信号,提供中继服务的中心用户对其所接收的叠加信号逐级解码并收集能量。第二时隙,中心用户将其第一时隙内所收集的能量作为额外功率资源,在优先保证自身通信质量的前提下对成功解码的边缘用户信息进行再编码转发。基于空间均质泊松点过程(Poisson point process,PPP)中心用户的位置模型,推导了中心用户与边缘用户平均中断概率的表达式,进行了蒙特卡罗仿真验证,同时分析了各仿真参数(中心用户分布半径、用户阈值速率、路径损耗指数等)与中心用户、边缘用户平均中断概率的关系。结果表明:所提方案可以改善边缘用户的下行接入中断性能和系统吞吐量。展开更多
Let N, N1, N2 be simple point processes on a LCCB space (E,) such that N=N1+N2, and p() be a measurable function with 0<p()<1 on (E,). Then any two of the following statements yield another two:(Ⅰ) N is a Poiss...Let N, N1, N2 be simple point processes on a LCCB space (E,) such that N=N1+N2, and p() be a measurable function with 0<p()<1 on (E,). Then any two of the following statements yield another two:(Ⅰ) N is a Poisson process;(Ⅱ) N1 is the p( )thinning of N, N2 is the (1-p())-thinning of N;(Ⅲ) N1 and N2 are independent;(Ⅳ) N1, N2 are Poisson processes with respect to a filtration {F(A), A}, whereF(A)={N1(B), N2(B), B, BA},i.e., for each bounded set A, N1(A) and N2(A) are Poisson variables, independent of F(A ).Indeed, only the fact, (Ⅱ)+(Ⅲ)(Ⅳ)+(Ⅰ), is new.展开更多
Sensing coverage is a fundamental design issue in wireless sensor networks(WSNs),while sensor scheduling ensures coverage degree to the monitored event and extends the network lifetime.In this paper,we address k-cover...Sensing coverage is a fundamental design issue in wireless sensor networks(WSNs),while sensor scheduling ensures coverage degree to the monitored event and extends the network lifetime.In this paper,we address k-coverage scheduling problem in dense WSNs,we maintain a connected k-coverage energy efficiently through a novel Hard-Core based Coordinated Scheduling(HCCS),in which hardcore is a thinning process in stochastic geometry that inhibits more than one active sensor covering any area redundantly in a minimum distance. As compared with existing coordinated scheduling,HCCS allows coordination between sensors with little communication overhead.Moreover,due to the traditional sensing models in k-coverage analysis is unsuitable to describe the characteristic of transmit channel in dense WSNs,we propose a novel sensing model integrating Rayleigh Fading and Distribution of Active sensors(RFDA),and derive the coverage measure and k-coverage probability for the monitored event under RFDA. In addition,we analyze the influence factors,i.e. the transmit condition and monitoring degree to the k-coverage probability. Finally,through Monte Carlo simulations,it is shown that the k-coverage probability of HCCS outperforms that of its random scheduling counterpart.展开更多
In this paper, we prove local uniqueness for multivalued stochastic differential equations with Poisson jumps. Then existence and uniqueness of global solutions is obtained under the conditions that the coefficients s...In this paper, we prove local uniqueness for multivalued stochastic differential equations with Poisson jumps. Then existence and uniqueness of global solutions is obtained under the conditions that the coefficients satisfy locally Lipschitz continuity and one-sided linear growth of b. Moreover, we also prove the Markov property of the solution and the existence of invariant measures for the corresponding transition semigroup.展开更多
非正交多址接入(non-orthogonal multiple access,NOMA)与无线携能通信(simultaneous wireless information and power transfer,SWIPT)技术的组合可提高无线系统的频谱效率,并能够解决用户节点的电能供应问题。然而,当能量收集器要恶...非正交多址接入(non-orthogonal multiple access,NOMA)与无线携能通信(simultaneous wireless information and power transfer,SWIPT)技术的组合可提高无线系统的频谱效率,并能够解决用户节点的电能供应问题。然而,当能量收集器要恶意窃听基站发送的机密信息时,SWIPT-NOMA系统的信息安全传输会受到威胁,为增强其物理层安全(physical layer security,PLS)性能,提出了一种采用发射天线选择和功率分割策略的SWIPT-NOMA系统PLS模型。如果各能量收集器的空间位置随机分布服从泊松点过程,利用空间泊松分布生成函数推导SWIPT-NOMA系统的安全中断概率和非零安全容量概率近似表达式。数值计算与仿真结果表明,所推导的表达式具有很高的准确性,且可用于研究窃听者密度、基站与远近端信息接收者之间的距离、基站发射天线数以及功率分割因子等参数对SWIPT-NOMA系统PLS性能的影响。展开更多
针对多扩展目标跟踪问题,提出了基于泊松点过程( Poisson Point Process, PPP )模型的多扩展目标跟踪的联合概率数据关联( Joint Probabilistic Data Association, JPDA )算法。首先,采用PPP对扩展目标进行测量建模,其次以“多对一”关...针对多扩展目标跟踪问题,提出了基于泊松点过程( Poisson Point Process, PPP )模型的多扩展目标跟踪的联合概率数据关联( Joint Probabilistic Data Association, JPDA )算法。首先,采用PPP对扩展目标进行测量建模,其次以“多对一”关联模型思想提出一种JPDA算法,从而计算运动目标的当前有效量测的边缘关联概率,然后结合该边缘关联概率以概率数据关联( Probability Data Association, PDA )的方式分别更新每个扩展目标的运动参数和形状参数向量,最后通过仿真实现了当扩展目标相互靠近或出现交叉时的跟踪。实验结果表明,在高杂波环境下,本文所提出的算法在计算时间和跟踪稳定上具有较明显的优势。展开更多
基金supported by the National High-Tech R&D Program (863 Program) under grant No. 2015AA01A705Beijing Municipal Science and Technology Commission research fund project under grant No. D151100000115002+1 种基金China Scholarship Council under grant No. 201406470038BUPT youth scientific research innovation program under grant No. 500401238
文摘Although small cell offloading technology can alleviate the congestion in macrocell, aggressively offloading data traffic from macrocell to small cell can also degrade the performance of small cell due to the heavy load. Because of collision and backoff, the degradation is significant especially in network with contention-based channel access, and finally decreases throughput of the whole network. To find an optimal fraction of traffic to be offloaded in heterogeneous network, we combine Markov chain with the Poisson point process model to analyze contention-based throughput in irregularly deployment networks. Then we derive the close-form solution of the throughput and find that it is a function of the transmit power and density of base stations.Based on this, we propose the load-aware offloading strategies via power control and base station density adjustment. The numerical results verify our analysis and show a great performance gain compared with non-load-aware offloading.
文摘本文研究了在毫微微蜂窝网络(femtocell network,FN)中,协同双小区系统的非正交多址接入(non-orthogonal multiple access,NOMA)与无线携能通信(simultaneous wireless information and power transfer,SWIPT)下行协作通信的中断性能,提出了一种边缘用户在邻基站及源基站随机中心用户共同协作的下行接入方案。所提方案共分为两个时隙:第一时隙内由两基站向所有用户广播叠加信号,提供中继服务的中心用户对其所接收的叠加信号逐级解码并收集能量。第二时隙,中心用户将其第一时隙内所收集的能量作为额外功率资源,在优先保证自身通信质量的前提下对成功解码的边缘用户信息进行再编码转发。基于空间均质泊松点过程(Poisson point process,PPP)中心用户的位置模型,推导了中心用户与边缘用户平均中断概率的表达式,进行了蒙特卡罗仿真验证,同时分析了各仿真参数(中心用户分布半径、用户阈值速率、路径损耗指数等)与中心用户、边缘用户平均中断概率的关系。结果表明:所提方案可以改善边缘用户的下行接入中断性能和系统吞吐量。
文摘Let N, N1, N2 be simple point processes on a LCCB space (E,) such that N=N1+N2, and p() be a measurable function with 0<p()<1 on (E,). Then any two of the following statements yield another two:(Ⅰ) N is a Poisson process;(Ⅱ) N1 is the p( )thinning of N, N2 is the (1-p())-thinning of N;(Ⅲ) N1 and N2 are independent;(Ⅳ) N1, N2 are Poisson processes with respect to a filtration {F(A), A}, whereF(A)={N1(B), N2(B), B, BA},i.e., for each bounded set A, N1(A) and N2(A) are Poisson variables, independent of F(A ).Indeed, only the fact, (Ⅱ)+(Ⅲ)(Ⅳ)+(Ⅰ), is new.
基金supported by the National Science Foundation of China under Grant 61271186
文摘Sensing coverage is a fundamental design issue in wireless sensor networks(WSNs),while sensor scheduling ensures coverage degree to the monitored event and extends the network lifetime.In this paper,we address k-coverage scheduling problem in dense WSNs,we maintain a connected k-coverage energy efficiently through a novel Hard-Core based Coordinated Scheduling(HCCS),in which hardcore is a thinning process in stochastic geometry that inhibits more than one active sensor covering any area redundantly in a minimum distance. As compared with existing coordinated scheduling,HCCS allows coordination between sensors with little communication overhead.Moreover,due to the traditional sensing models in k-coverage analysis is unsuitable to describe the characteristic of transmit channel in dense WSNs,we propose a novel sensing model integrating Rayleigh Fading and Distribution of Active sensors(RFDA),and derive the coverage measure and k-coverage probability for the monitored event under RFDA. In addition,we analyze the influence factors,i.e. the transmit condition and monitoring degree to the k-coverage probability. Finally,through Monte Carlo simulations,it is shown that the k-coverage probability of HCCS outperforms that of its random scheduling counterpart.
基金Supported by China Postdoctoral Science Foundation(Grant No.2012M521637)National Natural Science Foundation of China(Grant No.11171358)Doctor Fund of Ministry of Education(Grant No.20100171110038)
文摘In this paper, we prove local uniqueness for multivalued stochastic differential equations with Poisson jumps. Then existence and uniqueness of global solutions is obtained under the conditions that the coefficients satisfy locally Lipschitz continuity and one-sided linear growth of b. Moreover, we also prove the Markov property of the solution and the existence of invariant measures for the corresponding transition semigroup.
文摘非正交多址接入(non-orthogonal multiple access,NOMA)与无线携能通信(simultaneous wireless information and power transfer,SWIPT)技术的组合可提高无线系统的频谱效率,并能够解决用户节点的电能供应问题。然而,当能量收集器要恶意窃听基站发送的机密信息时,SWIPT-NOMA系统的信息安全传输会受到威胁,为增强其物理层安全(physical layer security,PLS)性能,提出了一种采用发射天线选择和功率分割策略的SWIPT-NOMA系统PLS模型。如果各能量收集器的空间位置随机分布服从泊松点过程,利用空间泊松分布生成函数推导SWIPT-NOMA系统的安全中断概率和非零安全容量概率近似表达式。数值计算与仿真结果表明,所推导的表达式具有很高的准确性,且可用于研究窃听者密度、基站与远近端信息接收者之间的距离、基站发射天线数以及功率分割因子等参数对SWIPT-NOMA系统PLS性能的影响。
文摘针对多扩展目标跟踪问题,提出了基于泊松点过程( Poisson Point Process, PPP )模型的多扩展目标跟踪的联合概率数据关联( Joint Probabilistic Data Association, JPDA )算法。首先,采用PPP对扩展目标进行测量建模,其次以“多对一”关联模型思想提出一种JPDA算法,从而计算运动目标的当前有效量测的边缘关联概率,然后结合该边缘关联概率以概率数据关联( Probability Data Association, PDA )的方式分别更新每个扩展目标的运动参数和形状参数向量,最后通过仿真实现了当扩展目标相互靠近或出现交叉时的跟踪。实验结果表明,在高杂波环境下,本文所提出的算法在计算时间和跟踪稳定上具有较明显的优势。
