In this study,the transmission capacity of VANETs in a highway scenario is analysed on the basis of a 1D line model and the carrier sense multiple access with collision avoidance(CSMA/CA)protocol.We describe the CSMA/...In this study,the transmission capacity of VANETs in a highway scenario is analysed on the basis of a 1D line model and the carrier sense multiple access with collision avoidance(CSMA/CA)protocol.We describe the CSMA/CA protocol used in IEEE802.11 p from the perspective of the geometric relationship amongst simultaneous transmitters.The desired channel and interfering channels are assumed to experience the same amount of path-loss and Rayleigh fading.On the basis of the proposed model,we analyse the attempted transmission probability of each road segment and the maximum intensity of active transmitters,including their theoretical values.Then,we employ the physical model to obtain the outage probability and derive the upper bound of the transmission capacity of a VANET,which is defined as the average spatial density of successful transmissions in the network.Simulation results indicate that the theoretical value offers a good bound on network capacity.展开更多
This work proposes a Field Programmable Gate Array(FPGA)-oriented architecture for the IEEE 8o2.11 Distributed Coordination Function(DCF)transceiver.Ⅵdescribe the functional blocks carrying out the Carrier Sense M ul...This work proposes a Field Programmable Gate Array(FPGA)-oriented architecture for the IEEE 8o2.11 Distributed Coordination Function(DCF)transceiver.Ⅵdescribe the functional blocks carrying out the Carrier Sense M ultip le Accesses with Collision Avoidance(CSMA/CA),develop the interfaces to the application lay er and the physical layer,and implement it on FPGA devices by utilizing Very-·high·-speed·-integrated_。circuit Hardware Description Language(VHDL).The novelty of our proposal is twofold.Firstly,all MAC parameters(i.e.,M ax/M in Contention Window,Data Unit I_ength,Fragmentation Threshold,Retry Limit,etc.)can be directly acessed and programmed from the application lay er interface,which is necessary to achieve better network performance in dynamic environ—ments.Secondly。the character based on FPGA makes the proposal more flexible and risk—reduced for the development of DCF—based wireless networks.such as M ANETs and sol'ware-defined-ra-dio-based cognitive ad hoc networks.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant No.61271184 and 61571065
文摘In this study,the transmission capacity of VANETs in a highway scenario is analysed on the basis of a 1D line model and the carrier sense multiple access with collision avoidance(CSMA/CA)protocol.We describe the CSMA/CA protocol used in IEEE802.11 p from the perspective of the geometric relationship amongst simultaneous transmitters.The desired channel and interfering channels are assumed to experience the same amount of path-loss and Rayleigh fading.On the basis of the proposed model,we analyse the attempted transmission probability of each road segment and the maximum intensity of active transmitters,including their theoretical values.Then,we employ the physical model to obtain the outage probability and derive the upper bound of the transmission capacity of a VANET,which is defined as the average spatial density of successful transmissions in the network.Simulation results indicate that the theoretical value offers a good bound on network capacity.
基金the National Natural Science Foundation of China
文摘This work proposes a Field Programmable Gate Array(FPGA)-oriented architecture for the IEEE 8o2.11 Distributed Coordination Function(DCF)transceiver.Ⅵdescribe the functional blocks carrying out the Carrier Sense M ultip le Accesses with Collision Avoidance(CSMA/CA),develop the interfaces to the application lay er and the physical layer,and implement it on FPGA devices by utilizing Very-·high·-speed·-integrated_。circuit Hardware Description Language(VHDL).The novelty of our proposal is twofold.Firstly,all MAC parameters(i.e.,M ax/M in Contention Window,Data Unit I_ength,Fragmentation Threshold,Retry Limit,etc.)can be directly acessed and programmed from the application lay er interface,which is necessary to achieve better network performance in dynamic environ—ments.Secondly。the character based on FPGA makes the proposal more flexible and risk—reduced for the development of DCF—based wireless networks.such as M ANETs and sol'ware-defined-ra-dio-based cognitive ad hoc networks.
