The 802.11 has emerged as the prominent wireless LAN technology as the mobile computing devices such as notebooks and PDA have replaced the desktop computers to be the main trend products. However, if the number of active stations is large, that is high-loading condition for the legacy DCF of 802.11, the capacity will be very low due to high collision costs. In this paper, we introduce the TDMA concept to partition all numerous active stations into several groups to avoid all stations transmitting the frames simultaneously. When Point Coordinator (PC, generally referring to AP) finds that the number of active stations (M) is large i.e. bigger than 8, it broadcasts number of groups (Ng) and group head (Nh) bits (such as 00000100 00000000) information in the TIM field of the beacon frame. Once all stations receive this instruction, the stations which last two LSB bits of the MAC address (IEEE EUI-48 or EUI-64) are 00 belonging to group 0 will transfer their frame first. On the contrary, all stations belonging to other groups will set their waiting time, that is, Network Allocation Vector (NAV) much more precisely. Analysis shows that the capacity of our GB-DCF will be near to the theoretical capacity limit of 802.11 WLAN even if the distributions of all active stations among all groups are not so uniform. This capacity could be independent of the number of active stations and CWMax (Contention window maximum). This grouping technique can also be applied to all DCF-based protocols such as EDCA (Enhanced Distributed Coordination Access), called GB-EDCA. In this article, we also simulate the behaviors of GB-EDCA and demonstrate that GB-EDCA can solve the delay jittering problem arising too many QoS stations running simultaneously.
802.11已成为一种重要的无线LAN技术,因为笔记本和PDA等移动计算设备已取代台式计算机成为主要趋势产品。但是,如果活动站点的数量很大,那就是802.11传统DCF的高负载条件,则由于高冲突成本 I>,容量将非常低。在本文中,我们引入了TDMA概念,将所有活动站点划分为几组,以避免所有站点同时发送帧。 I>当点协调器(PC,通常指AP)发现活动电台的数量( M I>)很大,即大于8时,它广播组数 B>( N g SUB> I>)和组头 B>( N h SUB> I>)位 B信标帧的 TIM I>字段中的>(例如00000100 00000000)信息。一旦所有站都接收到该指令,MAC地址的最后两个LSB位(IEEE EUI-48或EUI-64)的00属于组0的站将首先传输其帧。相反,属于其他组的所有站点将更精确地设置其等待时间,即网络分配向量(NAV)。分析表明,即使所有活动站点在所有组之间的分布不是很均匀,我们的GB-DCF的容量也将接近802.11 WLAN的理论容量极限。该容量可以独立于活动站点的数量和CW Max SUB>(争用窗口的最大值)。这种分组技术还可以应用于所有基于DCF的协议,例如EDCA(增强型分布式协调访问),称为GB-EDCA。在本文中,我们还模拟了GB-EDCA的行为,并证明GB-EDCA可以解决由于同时运行太多QoS站而引起的延迟抖动问题。 P>
National Taiwan University and Ming-Hsin University of Technology;
National Taiwan University;
机译:结合了不同物理层标准的IEEE 802.11e(EDCF)和IEEE 802.11(DCF)WLAN的性能分析
机译:结合了不同物理层标准的IEEE 802.11e(EDCF)和IEEE 802.11(DCF)WLAN的性能分析
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