【作者】 张艳艳；

【导师】 朱艺华；

【作者基本信息】 浙江工业大学 ， 计算机应用技术， 2011， 硕士

【摘要】 在基于IEEE 802.11标准的无线局域网络中,节点的无线收发器可以使用免执照的ISM无线频段(Industrial, Scientific, and Medical Bands)进行通信。因而,便携电脑和PDAs(Personal Digital Assistant)等移动计算设备大多配置了IEEE 802.11无线网络接口卡以方便接入到无线网络中。由于这些移动设备由能量非常有限的电池供电,因此,降低无线局域网中移动设备的能耗成为当前国内外的研究热点之一。考虑到节点的无线收发器的能耗在节点的能耗中占相当大的比例,IEEE 802.11标准引入了电源管理(Power management)允许节点在无数据需要传递时进入休眠状态——将节点的无线收发器切换到休眠模式(即关闭无线收发器),以达到节能的目的。本文基于上述电源管理策略,主要对具有基础设施的无线网络中的节点的无线收发器的节能进行研究,提出了流量自适应的休眠调度TASS(Traffic Adaptive Sleeping Schedule)策略。TASS策略将时间分为固定长度的时槽,时槽长度为信标间隔(Beacon Interval, BI)的整数倍,用调度序列来表示节点所处的清醒状态(包括接收数据、发送数据、以及空闲)或者休眠状态,利用Markov模型推导出节点平均休眠时槽个数、平均休眠时间长度、平均清醒时槽个数、平均清醒时间长度、节点的平均侦听信标次数、节点的平均状态切换次数、以及节点的总能耗等度量公式。此外,给出了一个优化节点的总能耗的优化模型。最后,应用MATLAB程序设计语言设计程序,针对流量符合Poisson分布和Gamma分布时,对TASS进行数值试验与分析。数值分析表明,本文所提出的TASS可以降低节点的无线收发器的能耗。更多还原

【Abstract】 In wireless local area network based IEEE 802.11 standard, wireless transceiver of node can use license-free ISM (Industrial, Scientific, and Medical Bands) radio band to communicate with others. Thus, most of mobile computing devices, such as portable computers, PDAs (Personal Digital Assistant) and so on, have equipped with IEEE 802.11 wireless network interface card to facilitate access to the wireless networks. Because these mobile devices are powered by the limited battery energy, reducing the power consumption becomes one of the current research hot spot at home and abroad.Given the energy consumption of wireless transceiver accounts for a significant proportion, IEEE 802.11 standard introduces power management, which allows nodes switch to sleep mode in the absence of data transferring. That can achieve the goal of saving energy by turning off wireless transceiver. Based on the above power management strategies, we mainly do some research on the the wireless transceiver energy efficiency in wireless infrastructure networks. We proposed a Traffic Adaptive Sleeping Schedule (TASS) strategy for it.Time is divided into fixed length time slot in TASS strategy. The length of time slot is the multiple of Beacon intervals. The scheduling sequence denotes the node’s statuses, which are awake status (including receive, send and idle) and sleep status. We use Markov model to derive a lot of measurement formula, such as the average numbers of sleep time slots, the length of sleep time, the average numbers of awake time slots, the length of awake time, the average numbers of listening beacon, the average numbers of state switching, the total energy consumption of the node. In addition, we give an optimization model of optimized total energy consumption. Finally, we use MATLAB to design the program, when network traffic obeys Poisson distribution and Gamma distribution. We do the numerical test and analysis of TASS. Numerical analysis shows that the proposed TASS can reduce the energy consumption of the wireless transceiver.更多还原