The handover speed is always vital for the further development of Wireless Local Area Network (WLAN), which is enjoying a fast growth. Based on the handover technology specified in IEEE 802.11 WLAN, Manageable Fast Ha...The handover speed is always vital for the further development of Wireless Local Area Network (WLAN), which is enjoying a fast growth. Based on the handover technology specified in IEEE 802.11 WLAN, Manageable Fast Handover (MFHO) mechanism is proposed to speed up handover at the Access Point (AP), meet handover demands of services with different Quality of Service (QoS), and ensure service continuity. Adopting a handover policy named 'Make-before-break', this mechanism enables wireless APs to control and manage handover between two stations based on improving Inter-Access Point Protocol (IAPP). Tests have been carried out to compare functions and performance of MFHO and IAPP-based handover technology. The test results prove that MFHO provides a higher successful handover ratio and better handover performance than IAPP-based handover technology.展开更多
Recently,cell-free(CF)massive multipleinput multiple-output(MIMO)becomes a promising architecture for the next generation wireless communication system,where a large number of distributed access points(APs)are deploye...Recently,cell-free(CF)massive multipleinput multiple-output(MIMO)becomes a promising architecture for the next generation wireless communication system,where a large number of distributed access points(APs)are deployed to simultaneously serve multiple user equipments(UEs)for improved performance.Meanwhile,a clustered CF system is considered to tackle the backhaul overhead issue in the huge connection network.In this paper,taking into account the more realistic mobility scenarios,we propose a hybrid small-cell(SC)and clustered CF massive MIMO system through classifications of the UEs and APs,and constructing the corresponding pairs to run in SC or CF mode.A joint initial AP selection of this paradigm for all the UEs is firstly proposed,which is based on the statistics of estimated channel.Then,closed-form expressions of the downlink achievable rates for both the static and moving UEs are provided under Ricean fading channel and Doppler shift effect.We also develop a semi-heuristic search algorithm to deal with the AP selection for the moving UEs by maximizing the weight average achievable rate.Numerical results demonstrate the performance gains and effective rates balancing of the proposed system.展开更多
无线局域网(WLAN)中可以对无线接入点(Access Point,AP)进行定位。该文提出一种基于概率密度的AP定位算法(Probability Density algorithm for Access Point Localization,PDAPL)。首先对实验区域进行分区;然后根据定向天线在不同位置...无线局域网(WLAN)中可以对无线接入点(Access Point,AP)进行定位。该文提出一种基于概率密度的AP定位算法(Probability Density algorithm for Access Point Localization,PDAPL)。首先对实验区域进行分区;然后根据定向天线在不同位置和不同角度收到的信号强度,计算AP落在各区域的概率,形成与密度有关的概率统计表;最后对AP的位置进行评估。实验结果表明,该文提出的算法采集数据少,只需在少量点和少量角度采集信号就可以得到较高的定位精度。与Driveby Loc,Distance和Ao A相比,得到相同的定位精度PDAPL所需要的测量点和测量角度只是Driveby Loc的一半左右,比Distance和Ao A所需要的更少;测量点和测量角度数量相同时,PDAPL的定位精度相对于Driveby Loc提升了50%左右。展开更多
文摘The handover speed is always vital for the further development of Wireless Local Area Network (WLAN), which is enjoying a fast growth. Based on the handover technology specified in IEEE 802.11 WLAN, Manageable Fast Handover (MFHO) mechanism is proposed to speed up handover at the Access Point (AP), meet handover demands of services with different Quality of Service (QoS), and ensure service continuity. Adopting a handover policy named 'Make-before-break', this mechanism enables wireless APs to control and manage handover between two stations based on improving Inter-Access Point Protocol (IAPP). Tests have been carried out to compare functions and performance of MFHO and IAPP-based handover technology. The test results prove that MFHO provides a higher successful handover ratio and better handover performance than IAPP-based handover technology.
基金This work was supported by the China National Key Research and Development Plan(No.2020YFB1807204).
文摘Recently,cell-free(CF)massive multipleinput multiple-output(MIMO)becomes a promising architecture for the next generation wireless communication system,where a large number of distributed access points(APs)are deployed to simultaneously serve multiple user equipments(UEs)for improved performance.Meanwhile,a clustered CF system is considered to tackle the backhaul overhead issue in the huge connection network.In this paper,taking into account the more realistic mobility scenarios,we propose a hybrid small-cell(SC)and clustered CF massive MIMO system through classifications of the UEs and APs,and constructing the corresponding pairs to run in SC or CF mode.A joint initial AP selection of this paradigm for all the UEs is firstly proposed,which is based on the statistics of estimated channel.Then,closed-form expressions of the downlink achievable rates for both the static and moving UEs are provided under Ricean fading channel and Doppler shift effect.We also develop a semi-heuristic search algorithm to deal with the AP selection for the moving UEs by maximizing the weight average achievable rate.Numerical results demonstrate the performance gains and effective rates balancing of the proposed system.
文摘无线局域网(WLAN)中可以对无线接入点(Access Point,AP)进行定位。该文提出一种基于概率密度的AP定位算法(Probability Density algorithm for Access Point Localization,PDAPL)。首先对实验区域进行分区;然后根据定向天线在不同位置和不同角度收到的信号强度,计算AP落在各区域的概率,形成与密度有关的概率统计表;最后对AP的位置进行评估。实验结果表明,该文提出的算法采集数据少,只需在少量点和少量角度采集信号就可以得到较高的定位精度。与Driveby Loc,Distance和Ao A相比,得到相同的定位精度PDAPL所需要的测量点和测量角度只是Driveby Loc的一半左右,比Distance和Ao A所需要的更少;测量点和测量角度数量相同时,PDAPL的定位精度相对于Driveby Loc提升了50%左右。
