Whenever the mobile station moves from the range of one access point and comes to the range of another access point a handoff process is occurred. This process takes a long time when using the IEEE 802.11 standard han...Whenever the mobile station moves from the range of one access point and comes to the range of another access point a handoff process is occurred. This process takes a long time when using the IEEE 802.11 standard handoff and this delay affect the real time and multimedia applications. This paper provides a layer 2 handoff process for the IEEE 802.11 that is able to eliminate the scanning delay and reduce the total handoff delay.展开更多
Performance evaluation of handover algorithms has been studied for mobile cellular network. Effects of averaging, hysteresis margin and shadow fading are investigated for different handoff algorithms. Probability of o...Performance evaluation of handover algorithms has been studied for mobile cellular network. Effects of averaging, hysteresis margin and shadow fading are investigated for different handoff algorithms. Probability of outage, handover delay and average number of handovers are considered as performance metrics. Different handover algorithms considered here are based on relative signal strength with hysteresis, relative signal strength with hysteresis and threshold, absolute signal strength and combined relative and absolute signal strength. Both analytical and simulation methods have been used in this paper. This study is important as performance analyses of cellular system, in presence of handoff, will be important for future generation wireless networks, for example, WiMAX, UMTS.展开更多
基于IEEE 802.11协议标准的无线局域网(wireless local area network,WLAN)由于其成本低、速度快、灵活方便等特点,目前已得到广泛的应用。由于WLAN的覆盖范围较小,当用户位置发生移动而离开当前WLAN范围进入新的WLAN覆盖范围时,用户将...基于IEEE 802.11协议标准的无线局域网(wireless local area network,WLAN)由于其成本低、速度快、灵活方便等特点,目前已得到广泛的应用。由于WLAN的覆盖范围较小,当用户位置发生移动而离开当前WLAN范围进入新的WLAN覆盖范围时,用户将会在多个WLAN覆盖范围内进行切换(handoff)。WLAN的切换过程是复杂的,执行该过程需要消耗网络大量的信令和进程负载。文中首先研究分析了WLAN的切换过程,分别对WLAN切换的触发、探寻、接入认证和重关联四个阶段的原理进行了总结;然后进一步分析了各个阶段的时延产生机制,并对整个切换过程各阶段的时延进行了总结和对比分析;最后,基于以上研究和分析,分别从平滑切换策略和快速切换策略两个方面,总结了基于IEEE 802.11标准的WLAN的切换方案的研究,并对这些研究的优劣进行了简要探讨。展开更多
文摘Whenever the mobile station moves from the range of one access point and comes to the range of another access point a handoff process is occurred. This process takes a long time when using the IEEE 802.11 standard handoff and this delay affect the real time and multimedia applications. This paper provides a layer 2 handoff process for the IEEE 802.11 that is able to eliminate the scanning delay and reduce the total handoff delay.
文摘Performance evaluation of handover algorithms has been studied for mobile cellular network. Effects of averaging, hysteresis margin and shadow fading are investigated for different handoff algorithms. Probability of outage, handover delay and average number of handovers are considered as performance metrics. Different handover algorithms considered here are based on relative signal strength with hysteresis, relative signal strength with hysteresis and threshold, absolute signal strength and combined relative and absolute signal strength. Both analytical and simulation methods have been used in this paper. This study is important as performance analyses of cellular system, in presence of handoff, will be important for future generation wireless networks, for example, WiMAX, UMTS.
文摘基于IEEE 802.11协议标准的无线局域网(wireless local area network,WLAN)由于其成本低、速度快、灵活方便等特点,目前已得到广泛的应用。由于WLAN的覆盖范围较小,当用户位置发生移动而离开当前WLAN范围进入新的WLAN覆盖范围时,用户将会在多个WLAN覆盖范围内进行切换(handoff)。WLAN的切换过程是复杂的,执行该过程需要消耗网络大量的信令和进程负载。文中首先研究分析了WLAN的切换过程,分别对WLAN切换的触发、探寻、接入认证和重关联四个阶段的原理进行了总结;然后进一步分析了各个阶段的时延产生机制,并对整个切换过程各阶段的时延进行了总结和对比分析;最后,基于以上研究和分析,分别从平滑切换策略和快速切换策略两个方面,总结了基于IEEE 802.11标准的WLAN的切换方案的研究,并对这些研究的优劣进行了简要探讨。
