Channel congestion occurs when the vehicular traffic density increases to a certain extent in Internet of Vehicles (IoV), even if there are only beacons in the wireless channel. To solve the problem, a Distributed-Weighted Fair Power Control (D-WFPC) algorithm was proposed. Firstly, considering the actual channel characteristics in IoV, the Nakagami-m fading channel model was used to establish the random channel model. Then, the mobility of the nodes in IoV was considered, and a power control optimization problem was established based on the Network Utility Maximization (NUM) model, which kept the local channel load under the threshold to avoid congestion. Finally, a distributed algorithm was designed by solving the problem with dual decomposition and iterative method. The transmit power of each vehicle was dynamically adjusted according to the beacons from neighbor vehicles. In the simulation experiment, compared with the fixed transmit power schemes, the D-FWPC algorithm reduced the delay and packet loss ratio effectively with the increase of traffic density, the highest reduction was up to 24% and 44% respectively. Compared with the Fair distributed Congestion Control with transmit Power (FCCP) algorithm, the D-FWPC algorithm had better performance all the way and the highest reduction in delay and packet loss ratio was up to 10% and 4% respectively. The simulation results show that the D-WFPC algorithm can converge quickly and ensure messages to be transmitted with low delay and high reliability in IoV.

In order to solve the low transmission reliability of the Vehicle to Vehicle (V2V) communication in the Internet of Vehicles (IoV), a Minimum Maximum Power-control Evaluation of Transmission Reliability (MMPETR) algorithm was proposed. Firstly, the effect on data transmission reliability of transmitted power control technology in mobile vehicles was studied and it was concluded that successful message transmission probability increased by improving transmitted power.Secondly, current Evaluation of Transmission Reliability (ETR) algorithm was improved by fully considering all the relationships between transmitted power for successfully sending warning message of the send vehicle and the minimum and maximum power of the vehicle itself. Finally, the appropriate numerical values of minimum transmitted power and maximum transmitted power of the send vehicle were given via simulation. The simulation results show that successful transmission probability of MMPETR algorithm is 4% higher than that of ETR algorithm, the MMPETR algorithm can effectively improve transmission reliability of the IoV system.

Max Weighted Queue (MWQ) control policy based on the theory of Lyapunov optimization is a cross-layer control policy that achieves queue stability and optimal delay performance. For the real-time and delay-sensitive demand in Device-to-Device (D2D) communication services, the MWQ algorithm, in which the Channel State Information (CSI) of PHY layer and the Queue State Information (QSI) of MAC layer are collectively considered, makes the maximum system throughput as the objective function and controls the power of D2D nodes dynamic. In this paper, a novel MWQ algorithm in the D2D communication was proposed. Compared to the algorithm with fixed power, the CSI-based algorithm and the QSI-based algorithm, the MWQ algorithm can decrease the average delay about 0.5 s when the average packets arrival rate exceeds 10 Mb/s and require less 26 dB power while having the same average delay. So the MWQ algorithm can achieve a good performance and have a reference to obtain low latency in D2D communication.