Under the background of intelligent transportation application, QoS for various services is different in wireless com-munication. Based on the MAC layer protocol, this paper analyzes the QoS in IEEE 802.11 MAC protoco...Under the background of intelligent transportation application, QoS for various services is different in wireless com-munication. Based on the MAC layer protocol, this paper analyzes the QoS in IEEE 802.11 MAC protocol framework, and proposes a new design of a Differentiation Enhanced Adaptive EDCA (enhanced distribution channel access) approach. The proposed approach adjusts the window zooming dynamically according to the collision rate in sending data frames, makes random offset, and further distinguishes the competition parameters of the data frames that have the same priority, so as to reduce the conflict among the data frames, and improve the channel utilization. Experiments with different service cases were conducted. The simulation results show that: comparing with the conventional EDCA method, the proposed approach can ensure that high priority services are sent with priority, and the overall QoS is highly improved.展开更多
分析城市轨道交通车地无线通信技术的应用现状,根据目前不断增长的无线带宽需求,将TD-LTE(time division-long term evolution,时分长期演进)技术作为最合适的车地无线通信方案。以郑州市轨道交通1号线为现实背景,利用轨道交通地下空间...分析城市轨道交通车地无线通信技术的应用现状,根据目前不断增长的无线带宽需求,将TD-LTE(time division-long term evolution,时分长期演进)技术作为最合适的车地无线通信方案。以郑州市轨道交通1号线为现实背景,利用轨道交通地下空间的真实环境,经过严密的分析研究,将合理的区间无线覆盖方案与先进的TD-LTE技术完美结合,实现城市轨道交通车地无线的流畅传输。展开更多
文摘Under the background of intelligent transportation application, QoS for various services is different in wireless com-munication. Based on the MAC layer protocol, this paper analyzes the QoS in IEEE 802.11 MAC protocol framework, and proposes a new design of a Differentiation Enhanced Adaptive EDCA (enhanced distribution channel access) approach. The proposed approach adjusts the window zooming dynamically according to the collision rate in sending data frames, makes random offset, and further distinguishes the competition parameters of the data frames that have the same priority, so as to reduce the conflict among the data frames, and improve the channel utilization. Experiments with different service cases were conducted. The simulation results show that: comparing with the conventional EDCA method, the proposed approach can ensure that high priority services are sent with priority, and the overall QoS is highly improved.
文摘分析城市轨道交通车地无线通信技术的应用现状,根据目前不断增长的无线带宽需求,将TD-LTE(time division-long term evolution,时分长期演进)技术作为最合适的车地无线通信方案。以郑州市轨道交通1号线为现实背景,利用轨道交通地下空间的真实环境,经过严密的分析研究,将合理的区间无线覆盖方案与先进的TD-LTE技术完美结合,实现城市轨道交通车地无线的流畅传输。
