The IEEE 802.11p is a standard in a vehicular communication system, known as Wireless Access in Vehicular Environment (WAVE). An implementation of that standard as the MAC Protocol in a high-density of nodes in Vehicu...The IEEE 802.11p is a standard in a vehicular communication system, known as Wireless Access in Vehicular Environment (WAVE). An implementation of that standard as the MAC Protocol in a high-density of nodes in Vehicular Ad-Hoc Networks (VANETs) may create a performance drawback, in particular for packet loss and delay whenever collisions happen. Introducing Time Division Multiple Access (TDMA) schemes can improve the performance. However, TDMA scheduling is difficult to manage the case of high-density of traffic, the high mobility of vehicles, and dynamic network topology. This journal proposes a clustered-based TDMA by traffic priority in VANETs. The clustered traffic is defined as high and low traffic priority and embedded in TDMA MAC Header. The evaluation result obtained through NS3 Simulator shows that the proposed approach performed better in a high-density of nodes.展开更多
This paper is focused on the multiuser implementation of fusion of radar and communication(RadCom)in internet-of-vehicles(IoV)scenarios.Traditional time-division multiple access(TDMA)technology degrades the velocity d...This paper is focused on the multiuser implementation of fusion of radar and communication(RadCom)in internet-of-vehicles(IoV)scenarios.Traditional time-division multiple access(TDMA)technology degrades the velocity detection performance of orthogonal frequency-division multiplexing(OFDM)-based RadCom systems.We propose a new TDMA approach for OFDM-based RadCom systems,where multiuser communication and radar detection are completed synchronously.We consider a continuous-wave TDMA OFDM structure in which random user data or Zadoff-Chu(ZC)sequences are transmitted in one symbol duration to ensure detection performance.As an application of interference cancellation method,user data demodulation and environment sensing can be simultaneously accomplished by our proposed approach.We carry out numerical evaluation and show wireless communication and radar detection performance over the continuous-wave TDMA OFDM-based RadCom approach.展开更多
针对水下无线传感器网络(UWSN,underwater sensor networks)提出以发送端为中心以连续时间为计量单位的冲突状态模型——局部冲突状态图及其分布式构建算法,并在此基础上设计了基于启发式规则的水下传感器网络TDMA协议(CT-TDMA,continuo...针对水下无线传感器网络(UWSN,underwater sensor networks)提出以发送端为中心以连续时间为计量单位的冲突状态模型——局部冲突状态图及其分布式构建算法,并在此基础上设计了基于启发式规则的水下传感器网络TDMA协议(CT-TDMA,continuous time based TDMA)。CT-TDMA利用UWSN中同一接收节点与不同发送节点之间链路时延的差异性,减少在目的端的接收帧之间的空闲时间,从而提高网络流量;基于启发式规则的分配算法,能有效缩短连续时间轴上的时刻分配所花费的时间。模拟实验证明:CT-TDMA与以ST-MAC为代表的按时隙分配的TDMA方案相比,网络流量提高了20%,数据分组的端到端时延降低了18%;与由全局知识所计算出的最优分配策略相比,网络流量达到了80%,端到端时延仅延长了12%。展开更多
文摘The IEEE 802.11p is a standard in a vehicular communication system, known as Wireless Access in Vehicular Environment (WAVE). An implementation of that standard as the MAC Protocol in a high-density of nodes in Vehicular Ad-Hoc Networks (VANETs) may create a performance drawback, in particular for packet loss and delay whenever collisions happen. Introducing Time Division Multiple Access (TDMA) schemes can improve the performance. However, TDMA scheduling is difficult to manage the case of high-density of traffic, the high mobility of vehicles, and dynamic network topology. This journal proposes a clustered-based TDMA by traffic priority in VANETs. The clustered traffic is defined as high and low traffic priority and embedded in TDMA MAC Header. The evaluation result obtained through NS3 Simulator shows that the proposed approach performed better in a high-density of nodes.
基金supported in part by the National Natural Science Foundation of China(No.61971092,No.62222121)in part by the Sichuan Province Foundation for Distinguished Young Scholars(2020JDJQ0023)in part by the Fundamental Research Funds for the Central Universities(ZYGX2020ZB045,ZYGX2019J123).
文摘This paper is focused on the multiuser implementation of fusion of radar and communication(RadCom)in internet-of-vehicles(IoV)scenarios.Traditional time-division multiple access(TDMA)technology degrades the velocity detection performance of orthogonal frequency-division multiplexing(OFDM)-based RadCom systems.We propose a new TDMA approach for OFDM-based RadCom systems,where multiuser communication and radar detection are completed synchronously.We consider a continuous-wave TDMA OFDM structure in which random user data or Zadoff-Chu(ZC)sequences are transmitted in one symbol duration to ensure detection performance.As an application of interference cancellation method,user data demodulation and environment sensing can be simultaneously accomplished by our proposed approach.We carry out numerical evaluation and show wireless communication and radar detection performance over the continuous-wave TDMA OFDM-based RadCom approach.
文摘针对水下无线传感器网络(UWSN,underwater sensor networks)提出以发送端为中心以连续时间为计量单位的冲突状态模型——局部冲突状态图及其分布式构建算法,并在此基础上设计了基于启发式规则的水下传感器网络TDMA协议(CT-TDMA,continuous time based TDMA)。CT-TDMA利用UWSN中同一接收节点与不同发送节点之间链路时延的差异性,减少在目的端的接收帧之间的空闲时间,从而提高网络流量;基于启发式规则的分配算法,能有效缩短连续时间轴上的时刻分配所花费的时间。模拟实验证明:CT-TDMA与以ST-MAC为代表的按时隙分配的TDMA方案相比,网络流量提高了20%,数据分组的端到端时延降低了18%;与由全局知识所计算出的最优分配策略相比,网络流量达到了80%,端到端时延仅延长了12%。
