An explicit congestion notification (ECN)-based distributed transport protocol,ARROW-WTCP (AcceleRate tRansmission towards Optimal Window size TCP for Wireless network),was proposed.The ARROW-WTCP enables feasible dep...An explicit congestion notification (ECN)-based distributed transport protocol,ARROW-WTCP (AcceleRate tRansmission towards Optimal Window size TCP for Wireless network),was proposed.The ARROW-WTCP enables feasible deployment of ARROW-TCP from wired to wireless networks by providing a joint design of source and router algorithms.The protocol obtains the actual capacity of the wireless channel by calculating the queue variation in base station (BS) and adjusts the congestion window by using the feedback from its bottleneck link.The simulation results show that the ARROW-WTCP achieves strong stability,max-min fairness in dynamic networks,fast convergence to efficiency without introducing much excess traffic,and almost full link utilization in the steady state.It outperforms the XCP-B (eXplicit Control Protocol Blind),the wireless version of XCP,in terms of stability,fairness,convergence and utilization in wireless networks.展开更多
针对IEEE 802.11p标准中导频数量有限,难以准确追踪车联万物(Vehicle-to-Everything,V2X)通信中时变信道的问题,学者们研究了数据导频辅助(Data Pilot Aided,DPA)信道估计方案。然而,这些经典DPA方案不能在完整的信噪比(Signal to Noise...针对IEEE 802.11p标准中导频数量有限,难以准确追踪车联万物(Vehicle-to-Everything,V2X)通信中时变信道的问题,学者们研究了数据导频辅助(Data Pilot Aided,DPA)信道估计方案。然而,这些经典DPA方案不能在完整的信噪比(Signal to Noise Ratio,SNR)范围内给出令人满意的效果,并且其估计结果的可靠性易受误差传播的影响。研究了一种新的信道估计方案,基于使用虚拟子载波的最小均方误差(Minimum Mean Square Error Using Virtual Pilots,MMSE-VP)方案,提出一种带有时间平均操作的改进MMSE(Improved MMSE,IMMSE)方案。IMMSE方案通过利用相邻正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)符号间信道的相关性来提高MMSE-VP方案在低SNR区域的性能,达到在整个SNR区域有良好表现的目的。联合深度学习技术,采用全连接神经网络(Fully Connected Neural Network,FCNN)作为IMMSE方案的非线性后处理模块,减少误差并获得更好的估计性能。在不同实验条件下的仿真结果表明,提出的信道估计方案可以适应调制方式和车辆速度的变化,能有效应对V2X通信中的信道估计问题。展开更多
车到车(vehicle to vehicle,V2V)通信因其复杂恶劣的信道环境,对系统的信道估计性能提出了更高的要求.针对IEEE 802.11p协议中导频过少无法准确跟踪频率选择性衰落信道的问题,提出了一种基于交错导频辅助的信道估计与跟踪方法.该方法将...车到车(vehicle to vehicle,V2V)通信因其复杂恶劣的信道环境,对系统的信道估计性能提出了更高的要求.针对IEEE 802.11p协议中导频过少无法准确跟踪频率选择性衰落信道的问题,提出了一种基于交错导频辅助的信道估计与跟踪方法.该方法将相邻符号的导频交错排布,利用相邻符号间信道的高度相关性,对前后时刻导频位置的信道估计结果进行插值运算,对V2V信道进行实时跟踪,在不改变IEEE 802.11p数据传输效率的前提下,其误码率性能在空旷高速的通信场景下明显优于基于原导频辅助的信道估计与跟踪方法.在所提出的交错导频框架下,针对不同V2V通信场景的特点选择合适的信道估计方案,可以较大程度地提高IEEE 802.11p的系统性能.展开更多
基金Projects(60873265,60903222) supported by the National Natural Science Foundation of China Project(IRT0661) supported by the Program for Changjiang Scholars and Innovative Research Team in University of China
文摘An explicit congestion notification (ECN)-based distributed transport protocol,ARROW-WTCP (AcceleRate tRansmission towards Optimal Window size TCP for Wireless network),was proposed.The ARROW-WTCP enables feasible deployment of ARROW-TCP from wired to wireless networks by providing a joint design of source and router algorithms.The protocol obtains the actual capacity of the wireless channel by calculating the queue variation in base station (BS) and adjusts the congestion window by using the feedback from its bottleneck link.The simulation results show that the ARROW-WTCP achieves strong stability,max-min fairness in dynamic networks,fast convergence to efficiency without introducing much excess traffic,and almost full link utilization in the steady state.It outperforms the XCP-B (eXplicit Control Protocol Blind),the wireless version of XCP,in terms of stability,fairness,convergence and utilization in wireless networks.
文摘针对IEEE 802.11p标准中导频数量有限,难以准确追踪车联万物(Vehicle-to-Everything,V2X)通信中时变信道的问题,学者们研究了数据导频辅助(Data Pilot Aided,DPA)信道估计方案。然而,这些经典DPA方案不能在完整的信噪比(Signal to Noise Ratio,SNR)范围内给出令人满意的效果,并且其估计结果的可靠性易受误差传播的影响。研究了一种新的信道估计方案,基于使用虚拟子载波的最小均方误差(Minimum Mean Square Error Using Virtual Pilots,MMSE-VP)方案,提出一种带有时间平均操作的改进MMSE(Improved MMSE,IMMSE)方案。IMMSE方案通过利用相邻正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)符号间信道的相关性来提高MMSE-VP方案在低SNR区域的性能,达到在整个SNR区域有良好表现的目的。联合深度学习技术,采用全连接神经网络(Fully Connected Neural Network,FCNN)作为IMMSE方案的非线性后处理模块,减少误差并获得更好的估计性能。在不同实验条件下的仿真结果表明,提出的信道估计方案可以适应调制方式和车辆速度的变化,能有效应对V2X通信中的信道估计问题。
