It is a hot issue in communication research field to select the best network for Heterogeneous Wireless Networks(HWNs),and it is also a difficult problem to reduce the handoff number of vertical handoff.In order to so...It is a hot issue in communication research field to select the best network for Heterogeneous Wireless Networks(HWNs),and it is also a difficult problem to reduce the handoff number of vertical handoff.In order to solve this problem,the paper proposes a multiple attribute network selection algorithm based on Analytic Hierarchy Process(AHP)and synergetic theory.The algorithm applies synergetics to network selection,considering the candidate network as a compound system composed of multiple attribute subsystems,and combines the subsystem order degree with AHP weight to obtain entropy of the compound system,which is opposite the synergy degree of a network system.The greater the synergy degree,the better the network performance.The algorithm takes not only the coordination of objective attributes but also Quality of Service(QoS)requirements into consideration,ensuring that users select the network with overall good performance.The simulation results show that the proposed algorithm can effectively reduce the handoff number and provide uses with satisfactory QoS according to different services.展开更多
In this paper we present an adaptive distributed cross-layer routing algorithm (ADCR) for hybrid wireless network with dedicated relay stations (HWN*). To support versatile multimedia communication for Mobile Terminal...In this paper we present an adaptive distributed cross-layer routing algorithm (ADCR) for hybrid wireless network with dedicated relay stations (HWN*). To support versatile multimedia communication for Mobile Terminals (MTs), the HWN* integrates a cellular network, an ad hoc network and fixed relay nodes (RNs). A MT may borrow cellular data channels that are available thousands mile away via secure multi-hop RNs, where RNs are placed at flexible locations in the network. The MT can also communicate with each other or access internet ubiquitously. We discuss cross media access and network layers routing issues. The ADCR establishes routing paths across RNs or cellular network while providing appropriate QoS (quality of service). Through simulation, we verify the routing performance benefits of HWN* over conventional cellular systems and other hybrid network frameworks. It is anticipated that the simulation results reported in this paper will serve as a guideline for research based on distributed source routing involving heterogeneous wireless technologies.展开更多
This study presents a new non-parametric measure of heat waves called heat wave norm (HWN), which allows quantifying and qualifying the magnitude of the summer heat wave events in the Bechar region located northwest o...This study presents a new non-parametric measure of heat waves called heat wave norm (HWN), which allows quantifying and qualifying the magnitude of the summer heat wave events in the Bechar region located northwest of the Algerian Sahara over the period 1951-2010. The index, based on the analysis of daily maximum and minimum temperatures by adding them, integrated two dimensions at the same time: the duration and the excess heat. The results show an increase in the intensity and frequency of extreme events. More specifically, from the 1980s, it is possible to observe the propagation of extreme and very extreme and super extreme heat waves in recent decades with maximum presence during the period 1990-2010. In general, it can be said that the trend of excessive warming is clearly displayed in the Algerian Sahara, generally classified as a hot region.展开更多
In the future, the wireless communication networks can be visualized as the integration of different radio access technologies （RATs）, which are referred to as heterogeneous wireless networks （HWNs）. In this paper...In the future, the wireless communication networks can be visualized as the integration of different radio access technologies （RATs）, which are referred to as heterogeneous wireless networks （HWNs）. In this paper, the traffic split scheme in the HWNs integrating the long term evolution （LTE） and the high speed downlink packet access （HSDPA） networks is investigated. Assuming that the networks can support multi-homing access and the user can be served by both networks simultaneously, the traffic split problem is described as an optimization problem with the aim of maximizing the throughput. By solving the problem, the dynamic traffic split scheme is proposed. The split ratios in the scheme should be proportional to the transmission rates in theory, which are hard to be described in the closed forms. Then the adaptive algorithm is proposed to obtain the split ratios. Simulation results show that the scheme with the adaptive algorithm provides better performance than the scheme without it over the additive white Gaussian noise （AWGN） fading channel and Rayleigh fading channel.展开更多
基金Supported by the Major State Basic Research Development Program of China(973 Program)(No.2013CB329005)the National Natural Science Foundation of China(No.61171094)+1 种基金the National Science & Technology Key Project(No.2011ZX03001-006-02.No.2011ZX03005004-03)the Key Project of Jiangsu Provincial Natural Science Foundation(No.BK2011027)
文摘It is a hot issue in communication research field to select the best network for Heterogeneous Wireless Networks(HWNs),and it is also a difficult problem to reduce the handoff number of vertical handoff.In order to solve this problem,the paper proposes a multiple attribute network selection algorithm based on Analytic Hierarchy Process(AHP)and synergetic theory.The algorithm applies synergetics to network selection,considering the candidate network as a compound system composed of multiple attribute subsystems,and combines the subsystem order degree with AHP weight to obtain entropy of the compound system,which is opposite the synergy degree of a network system.The greater the synergy degree,the better the network performance.The algorithm takes not only the coordination of objective attributes but also Quality of Service(QoS)requirements into consideration,ensuring that users select the network with overall good performance.The simulation results show that the proposed algorithm can effectively reduce the handoff number and provide uses with satisfactory QoS according to different services.
文摘In this paper we present an adaptive distributed cross-layer routing algorithm (ADCR) for hybrid wireless network with dedicated relay stations (HWN*). To support versatile multimedia communication for Mobile Terminals (MTs), the HWN* integrates a cellular network, an ad hoc network and fixed relay nodes (RNs). A MT may borrow cellular data channels that are available thousands mile away via secure multi-hop RNs, where RNs are placed at flexible locations in the network. The MT can also communicate with each other or access internet ubiquitously. We discuss cross media access and network layers routing issues. The ADCR establishes routing paths across RNs or cellular network while providing appropriate QoS (quality of service). Through simulation, we verify the routing performance benefits of HWN* over conventional cellular systems and other hybrid network frameworks. It is anticipated that the simulation results reported in this paper will serve as a guideline for research based on distributed source routing involving heterogeneous wireless technologies.
文摘This study presents a new non-parametric measure of heat waves called heat wave norm (HWN), which allows quantifying and qualifying the magnitude of the summer heat wave events in the Bechar region located northwest of the Algerian Sahara over the period 1951-2010. The index, based on the analysis of daily maximum and minimum temperatures by adding them, integrated two dimensions at the same time: the duration and the excess heat. The results show an increase in the intensity and frequency of extreme events. More specifically, from the 1980s, it is possible to observe the propagation of extreme and very extreme and super extreme heat waves in recent decades with maximum presence during the period 1990-2010. In general, it can be said that the trend of excessive warming is clearly displayed in the Algerian Sahara, generally classified as a hot region.
基金supported by the Research Fund of ZTE Corporation
文摘In the future, the wireless communication networks can be visualized as the integration of different radio access technologies （RATs）, which are referred to as heterogeneous wireless networks （HWNs）. In this paper, the traffic split scheme in the HWNs integrating the long term evolution （LTE） and the high speed downlink packet access （HSDPA） networks is investigated. Assuming that the networks can support multi-homing access and the user can be served by both networks simultaneously, the traffic split problem is described as an optimization problem with the aim of maximizing the throughput. By solving the problem, the dynamic traffic split scheme is proposed. The split ratios in the scheme should be proportional to the transmission rates in theory, which are hard to be described in the closed forms. Then the adaptive algorithm is proposed to obtain the split ratios. Simulation results show that the scheme with the adaptive algorithm provides better performance than the scheme without it over the additive white Gaussian noise （AWGN） fading channel and Rayleigh fading channel.
