以太网交换机仅依据目的介质访问控制(Media Access Control,MAC)子层地址进行数据转发,指定源组播(Source Specific Multicast,SSM)数据进入交换机后可能被转发至其他频道的订阅用户。针对此问题,在分析了SSM协议模型的以太网交换问题...以太网交换机仅依据目的介质访问控制(Media Access Control,MAC)子层地址进行数据转发,指定源组播(Source Specific Multicast,SSM)数据进入交换机后可能被转发至其他频道的订阅用户。针对此问题,在分析了SSM协议模型的以太网交换问题的基础上,提出了SSM数据标识及源标识的加入方法,详细设计了SSM转发表的建立过程,给出了SSM数据的转发流程,并对方法的可行性进行了仿真验证。展开更多
随着无线服务的日趋多样化和业务量的爆炸式增长,服务质量(quality of service,QoS)的保障是下一代无线局域网(wireless local area network,WLAN)的重要目标之一。正交频分多址(orthogonal frequency division multiple access,OFDMA)...随着无线服务的日趋多样化和业务量的爆炸式增长,服务质量(quality of service,QoS)的保障是下一代无线局域网(wireless local area network,WLAN)的重要目标之一。正交频分多址(orthogonal frequency division multiple access,OFDMA)是下一代WLAN的重要特性,然而已有的关于下一代WLAN的多址接入协议研究或者较少关注QoS保障,或者对于公平性保障较差。文章提出了一种面向QoS的下一代WLAN OFDMA多址接入协议:QoS-OFDMA。该协议引入了2次OFDMA并行随机接入的思想,第1次随机接入不区分业务优先级,从而保障了公平性;进一步允许第1次随机接入失败的高优先级用户,在分配剩余的可用子信道上,进行第2次随机接入,从而保障了高优先级业务的QoS。仿真结果表明,与RA-OFDMA协议和OMAX协议相比,QoS-OFDMA高优先级业务吞吐量分别提升了22.05%和89.6%,同时很好地保障了低优先级业务公平性。展开更多
The Wireless Gigabit Alliance （WiGig） and I EEE 802.11 ad are developing a multigigabit wireless personal and local area network （WPAN/ WLAN） specification in the 60 GHz millimeter wave band. Chipset manufacturers...The Wireless Gigabit Alliance （WiGig） and I EEE 802.11 ad are developing a multigigabit wireless personal and local area network （WPAN/ WLAN） specification in the 60 GHz millimeter wave band. Chipset manufacturers, original equipment manufacturers （OEMs）, and telecom companies are also assisting in this development. 60 GHz millimeter wave transmission will scale the speed of WLANs and WPANs to 6.75 Gbit/s over distances less than 10 meters. This technology is the first of its kind and will eliminate the need for cable around personal computers, docking stations, and other consumer electronic devices. High-definition multimedia interface （HDMI）, display port, USB 3.0, and peripheral component interconnect express （PCle） 3.0 cables will all be eliminated. Fast downloads and uploads, wireless sync, and multi-gigabit-per-second WLANs will be possible over shorter distances. 60 GHz millimeter wave supports fast session transfer （FST） protocol, which makes it backward compatible with 5 GHz or 2.4 GHz WLAN so that end users experience the same range as in today＇ s WLANs. IEEE 802.1 lad specifies the physical （PHY） sublayer and medium access control （MAC） sublayer of the protocol stack. The MAC protocol is based on time-division multiple access （TDMA）, and the PHY layer uses single carrier （SC） and orthogonal frequency division multiplexing （OFDM） to simultaneously enable low-power, high-performance applications.展开更多
文摘以太网交换机仅依据目的介质访问控制(Media Access Control,MAC)子层地址进行数据转发,指定源组播(Source Specific Multicast,SSM)数据进入交换机后可能被转发至其他频道的订阅用户。针对此问题,在分析了SSM协议模型的以太网交换问题的基础上,提出了SSM数据标识及源标识的加入方法,详细设计了SSM转发表的建立过程,给出了SSM数据的转发流程,并对方法的可行性进行了仿真验证。
文摘随着无线服务的日趋多样化和业务量的爆炸式增长,服务质量(quality of service,QoS)的保障是下一代无线局域网(wireless local area network,WLAN)的重要目标之一。正交频分多址(orthogonal frequency division multiple access,OFDMA)是下一代WLAN的重要特性,然而已有的关于下一代WLAN的多址接入协议研究或者较少关注QoS保障,或者对于公平性保障较差。文章提出了一种面向QoS的下一代WLAN OFDMA多址接入协议:QoS-OFDMA。该协议引入了2次OFDMA并行随机接入的思想,第1次随机接入不区分业务优先级,从而保障了公平性;进一步允许第1次随机接入失败的高优先级用户,在分配剩余的可用子信道上,进行第2次随机接入,从而保障了高优先级业务的QoS。仿真结果表明,与RA-OFDMA协议和OMAX协议相比,QoS-OFDMA高优先级业务吞吐量分别提升了22.05%和89.6%,同时很好地保障了低优先级业务公平性。
文摘The Wireless Gigabit Alliance （WiGig） and I EEE 802.11 ad are developing a multigigabit wireless personal and local area network （WPAN/ WLAN） specification in the 60 GHz millimeter wave band. Chipset manufacturers, original equipment manufacturers （OEMs）, and telecom companies are also assisting in this development. 60 GHz millimeter wave transmission will scale the speed of WLANs and WPANs to 6.75 Gbit/s over distances less than 10 meters. This technology is the first of its kind and will eliminate the need for cable around personal computers, docking stations, and other consumer electronic devices. High-definition multimedia interface （HDMI）, display port, USB 3.0, and peripheral component interconnect express （PCle） 3.0 cables will all be eliminated. Fast downloads and uploads, wireless sync, and multi-gigabit-per-second WLANs will be possible over shorter distances. 60 GHz millimeter wave supports fast session transfer （FST） protocol, which makes it backward compatible with 5 GHz or 2.4 GHz WLAN so that end users experience the same range as in today＇ s WLANs. IEEE 802.1 lad specifies the physical （PHY） sublayer and medium access control （MAC） sublayer of the protocol stack. The MAC protocol is based on time-division multiple access （TDMA）, and the PHY layer uses single carrier （SC） and orthogonal frequency division multiplexing （OFDM） to simultaneously enable low-power, high-performance applications.
