Optimal relay selecting method based on power control technology in internet of vehicles

Abstract

The invention discloses an optimal relay selecting method based on a power control technology in internet of vehicles. The optimal relay selecting method comprises the following steps of (1) calculating distances of a moving vehicle relative to neighbor nodes by obtaining current GPS position vector information of vehicles of all of neighbors; (2) respectively calculating transmitting power correspondingly required by reliable transmission of all of neighbor nodes based on a physical channel attenuation model; (3) calculating MAC layer transmission delay caused by all of transmitting power according to the 802.11p protocol; (4) synthesizing two indexes including the reliability and the delay of data transmission, calculating the priority level of each neighbor to be selected as a relay and selecting the neighbor with the highest priority level as an optimal relay for current information transmission. The optimal relay selecting method utilizes the characteristic that an adjustable range of transmitting power of a vehicle-mounted communication device is wide, various factors including physical channel attenuation, MAC layer message collision, retransmission delay and the like are comprehensively considered to select the optimal relay, messages in the internet of vehicles are reliably transmitted in real time in a large-range mode, and the application prospect is very broad.

Description

technical field [0001] The invention belongs to the technical field of wireless transmission and data distribution in the Internet of Vehicles, and in particular relates to an optimal relay selection method based on transmission power control technology. When the source node selects the relay from adjacent vehicles, two factors, wireless signal attenuation and MAC layer transmission delay, are taken into account, and the purpose of reliable and efficient information distribution in the Internet of Vehicles is realized. Background technique [0002] In the Vehicular Ad-hoc Network (VANET), high-speed moving vehicles share traffic road information in real time through a wireless ad-hoc network to improve traffic safety. The information transmitted between vehicles is usually divided into two types: periodic Beacons and accident-triggered Warning messages. Among them, the Beacons message mainly includes the current vehicle's speed, acceleration, GPS position vector and other i...

AI Technical Summary

Problems solved by technology

A current common solution is to modify the routing protocol in the traditional mobile ad hoc network and transplant it to the Internet of Vehicles, but the high-speed movement of nodes in the Internet of Vehicles, the rapid changes in network connectivity and topology, and the vehicle trajectory are limited. The fixed structure of roads and other characteristics make this kind of scheme low reliability and large end-to-end delay in the data distribution process; another kind of thinking is shown in the literature [H.Lu, etc, "Balancing broadcast reliability and transmission range in VANETs", According to IEEE Vehicular Networking Conference, pp247-254, USA, December 2010], according to the vehicle density, real-time adjustment of wireless transmission power improves the network connectivity of mobile vehicles. By increasing the transmission power, the signal strength can be improved, and information can be transmitted to distant neighbors. The probability that a node successfully receives

However, the larger communication radius also increases the probability of MAC layer data transmission collisions and multiple retransmissions, which intensifies the single-hop MAC transmission delay.

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