Energy efficiency plays vital roles in wireless communication system due to the “energy limited battery service” of a mobile station (MS). To ensure longer battery life in WiMAX, a new protocol has been introduced i...Energy efficiency plays vital roles in wireless communication system due to the “energy limited battery service” of a mobile station (MS). To ensure longer battery life in WiMAX, a new protocol has been introduced in its IEEE802.16m version. This new sleep mode has extended listening window and adjustable sleep cycle length. In this paper, we analyze the probability of attaining at three states: serving state, state of timer inactivity and silent state in a simplified statistical model using traffic parameters of arrival rate, pdf (probability density function) of interarrival time and its threshold value. Finally we developed a new state transition chain of the above three states of a MS of IEEE802.16m and solved the chain in closed form.展开更多
文摘Energy efficiency plays vital roles in wireless communication system due to the “energy limited battery service” of a mobile station (MS). To ensure longer battery life in WiMAX, a new protocol has been introduced in its IEEE802.16m version. This new sleep mode has extended listening window and adjustable sleep cycle length. In this paper, we analyze the probability of attaining at three states: serving state, state of timer inactivity and silent state in a simplified statistical model using traffic parameters of arrival rate, pdf (probability density function) of interarrival time and its threshold value. Finally we developed a new state transition chain of the above three states of a MS of IEEE802.16m and solved the chain in closed form.
文摘目的快速眼动睡眠行为障碍(rapid eye movement sleep behavior disorder,RBD)是帕金森病(Parkinson's disease,PD)常见的非运动症状且是重要预后因素。本研究通过静息态功能磁共振成像,利用度中心度(degreecentrality,DC)和低频振幅(amplitudes of low-frequency fluctuation,ALFF)分析PD伴RBD和不伴有RBD患者组以及健康对照组三组间DC值和ALFF值,探索PD伴RBD患者脑功能活动特征及RBD特异性脑区,探究RBD发生的病理机制。材料与方法招募20例伴有RBD的PD患者(PD-RBD组)、40例无RBD的PD患者(PD-nonRBD组)和44例年龄性别匹配的健康对照(健康对照组),三组被试均接受磁共振扫描。利用静息态数据计算DC值和ALFF值,探测脑功能特征。结果方差分析结果显示三组间DC值主效应脑区为右侧中央前回、颞上回、小脑、额中回(P<0.05,FDR校正);ALFF值主效应脑区为左侧海马旁回、楔叶、舌回(P<0.05,FDR校正)。进一步分析发现相比于PD-nonRBD组,PD-RBD患者表现为右侧额中回DC值升高(t=4.02;P=0.007,FDR校正);左侧楔前叶DC值降低(t=5.30;P=0.009,FDR校正)。相比于健康对照组,PD-RBD患者表现为左侧额上回、小脑、右侧颞上回、左侧颞中回、额中回的DC值升高(P<0.05,FDR校正);左侧中央前回、颞上回和颞中回的DC值降低(P<0.05,FDR校正);右侧楔叶ALFF值降低(P<0.05,FDR校正)。结论PD-RBD在DC和ALFF上有独特的影像学特征,特别是右侧额中回、左侧楔前叶的功能异常可能与PD患者RBD的发生密切相关。
