VAPT: VANET adaptive power transmission nodes connectivity

Recently, vehicular Ad-Hoc Network (VANET) has received considerable attention where its safety applications and Internet users accessing related application are expected to be supported. Safety applications play an important role to avoid road accidents. Even in the case if the accident is unavoidable, these applications can at least minimize the impact of accidents. The main goal ofV ANET is to provide safety to passengers and the real-time safety message exchanging is one of the most important issues in VANETs. Safety applications are a delay-sensitive and they mainly rely on reliable inter-vehicle communication. In VANET, the rapid and frequent changes in vehicle mobility create a highly dynamic topology. Due to this, VANET faces challenges in maintaining the connectivity. Therefore, by using fixed transmission power in VANET, it will give adverse effects on the connectivity. Transmission power is directly proportional to transmission range. Using fixed transmission power/transmission range leads to many disadvantages; for example, when vehicles are distributed densely, more nodes have to share the medium, causing more contentions, collisions, resulted to delays that reduce network capacity. In addition, the contention window ( CW) and bit rate (BR) also play a significant role in the transmission process. Using a bigger size of CW will reduce the packet loss, hence increase the throughput and Packet Delivery Ratio (PDR). However, the bigger size of CW will increase the delay. While for BR, the delay can be minimized by using a higher BR, but it will reduce the PDR and throughput. This is due to the fact that higher BR resulted in fast transmission rate which increases the packet loss. Hence, this research work is proposed in order to overcome these problems. The main objective of this research is to propose a new power control mechanism to maintain network connectivity that can minimize the delay and the uses of energy and improve the PDR. The proposed VANET Adaptive Power Transmission (VAPT) mechanism modified the MAC layer by applying oflline optimization using Differential Evolution (DE) algorithm to inspect three parameters (transmission power, BR, and CW) and to fmd their optimum value. These optimum values are then used to optimize the network performances. To achieve the objective of this research, extensive experiments were conducted to investigate how the variable value of transmission power can influence the connectivity of the network in different VANET scenarios and traffic load parameters. The results show that the proposed VAPT optimization mechanism improves the performance of multiple VANET scenarios. The highway scenario in different packet size simulation shows the highest performance improvement in terms of delay and energy consumption. The delay is improved by 55.07% in average and the energy consumption is improved by 54.44% in average. While for the PDR, the highest improvement is 17.35% in average is shown by hybrid scenario in different packet rate simulations. Then, the highest improvement for throughput is 17.78% in average, also shown by the hybrid scenario in different packet rate simulations.