基于接收端通告的TCP(TCP-Rab,receiver advertisement based TCP)协议是我们实现的一种新的TCP协议,在文献[1]中对TCP-Rab的算法设计、实现进行了详细阐述。本文对TCP-Rab进行了少量改进,重点导出了TCP-Rab的吞吐量性能模型,并对TCP-Ra...基于接收端通告的TCP(TCP-Rab,receiver advertisement based TCP)协议是我们实现的一种新的TCP协议,在文献[1]中对TCP-Rab的算法设计、实现进行了详细阐述。本文对TCP-Rab进行了少量改进,重点导出了TCP-Rab的吞吐量性能模型,并对TCP-Rab进行了试验研究。该模型采用统计的方法,在导出TCP-Rab的吞吐量性能模型的时候,不仅考虑了TCP连接的拥塞避免阶段对吞吐量的影响,也考虑了慢启动阶段对吞吐量的影响,同时还考虑了一个发送窗口内多个数据包随机丢失对吞吐量的影响,因此该模型能适用于实际的网络环境中。展开更多
最近的研究表明,在当前网络未启用SACK选项的TCP流中,有超过一半的数据流采用TCP New Reno的快速恢复算法.而Padhye提出的基于TCP Reno的TCP吞吐量分析模型,不能准确反映TCP New Reno数据流的吞吐量.Padhye模型在建立过程中采用猝发性...最近的研究表明,在当前网络未启用SACK选项的TCP流中,有超过一半的数据流采用TCP New Reno的快速恢复算法.而Padhye提出的基于TCP Reno的TCP吞吐量分析模型,不能准确反映TCP New Reno数据流的吞吐量.Padhye模型在建立过程中采用猝发性丢包模型,同时忽略了快速恢复阶段和超时后的慢启动阶段,影响了预测的准确性.基于此,提出了一种基于TCP New Reno的吞吐量分析模型.在分析过程中,采用了更符合真实网络丢包特征的丢包模型,并且充分考虑了快速恢复阶段和超时后的慢启动阶段对吞吐量的影响.仿真实验表明,该模型可以准确地预测TCP New Reno数据流的吞吐量.展开更多
A novel distributed cognitive radio multichannel medium access protocol without common control channel was proposed.The protocol divided a transmission interval into two parts for exchanging control information and da...A novel distributed cognitive radio multichannel medium access protocol without common control channel was proposed.The protocol divided a transmission interval into two parts for exchanging control information and data,respectively.In addition to evaluating system saturation throughput of the proposed protocol,a three-dimensional multi channel Markov chain model to describe the sate of the cognitive users (CUs) in dynamic spectrum access was presented.The proposed analysis was applied to the packet transmission schemes employed by the basic,RTS/CTS access mechanism adopted in the normal IEEE 802.11.Analyzing the advantage of the two methods,a hybrid access mechanism was proposed to improve the system throughput.The simulation results show that the experiment results are close to the value computed by the model (less than 5%),and the proposed protocol significantly improves the performance of the system throughput by borrowing the licensed spectrum.By analyzing the dependence of throughput on system parameters,hybrid mechanism dynamically selecting access mechanism can maintain high throughput.展开更多
文摘基于接收端通告的TCP(TCP-Rab,receiver advertisement based TCP)协议是我们实现的一种新的TCP协议,在文献[1]中对TCP-Rab的算法设计、实现进行了详细阐述。本文对TCP-Rab进行了少量改进,重点导出了TCP-Rab的吞吐量性能模型,并对TCP-Rab进行了试验研究。该模型采用统计的方法,在导出TCP-Rab的吞吐量性能模型的时候,不仅考虑了TCP连接的拥塞避免阶段对吞吐量的影响,也考虑了慢启动阶段对吞吐量的影响,同时还考虑了一个发送窗口内多个数据包随机丢失对吞吐量的影响,因此该模型能适用于实际的网络环境中。
文摘最近的研究表明,在当前网络未启用SACK选项的TCP流中,有超过一半的数据流采用TCP New Reno的快速恢复算法.而Padhye提出的基于TCP Reno的TCP吞吐量分析模型,不能准确反映TCP New Reno数据流的吞吐量.Padhye模型在建立过程中采用猝发性丢包模型,同时忽略了快速恢复阶段和超时后的慢启动阶段,影响了预测的准确性.基于此,提出了一种基于TCP New Reno的吞吐量分析模型.在分析过程中,采用了更符合真实网络丢包特征的丢包模型,并且充分考虑了快速恢复阶段和超时后的慢启动阶段对吞吐量的影响.仿真实验表明,该模型可以准确地预测TCP New Reno数据流的吞吐量.
基金Project(61071104) supported by the National Natural Science Foundation of China
文摘A novel distributed cognitive radio multichannel medium access protocol without common control channel was proposed.The protocol divided a transmission interval into two parts for exchanging control information and data,respectively.In addition to evaluating system saturation throughput of the proposed protocol,a three-dimensional multi channel Markov chain model to describe the sate of the cognitive users (CUs) in dynamic spectrum access was presented.The proposed analysis was applied to the packet transmission schemes employed by the basic,RTS/CTS access mechanism adopted in the normal IEEE 802.11.Analyzing the advantage of the two methods,a hybrid access mechanism was proposed to improve the system throughput.The simulation results show that the experiment results are close to the value computed by the model (less than 5%),and the proposed protocol significantly improves the performance of the system throughput by borrowing the licensed spectrum.By analyzing the dependence of throughput on system parameters,hybrid mechanism dynamically selecting access mechanism can maintain high throughput.
