Development of potential methods for testing congestion control algorithm implemented in vehicle-to-vehicle communications

Abstract

Objective: A channel congestion problem might occur when the traffic density increases because the number of basic safety messages carried on the communication channel also increases in vehicle-to-vehicle communications. A remedy algorithm proposed in SAE J2945/1 is designed to address the channel congestion issue by decreasing transmission frequency and radiated power. This study is to develop potential test procedures for evaluating or validating the congestion control algorithm. Methods: Simulations of a reference unit transmitting at a higher frequency are implemented to emulate a number of onboard equipment (OBE) transmitting at the normal interval of 100 ms (10 Hz). When the transmitting interval is reduced to 1.25 ms (800 Hz), the reference unit emulates 80 vehicles transmitting at 10 Hz. By increasing the number of reference units transmitting at 800 Hz in the simulations, the corresponding channel busy percentages are obtained. An algorithm for Global Positioning System (GPS) data generation of virtual vehicles is developed for facilitating the validation of transmission intervals in the congestion control algorithm. Results: Channel busy percentage is the channel busy time over a specified period of time. Three or 4 reference units are needed to generate channel busy percentages between 50 and 80%, and 5 reference units can generate channel busy percentages above 80%. The proposed test procedures can verify the operation of congestion control algorithm when channel busy percentages are between 50 and 80% and above 80%. By using a GPS data generation algorithm, the test procedures can also verify the transmission intervals when traffic densities are 80 and 200 vehicles in a radius of 100 m. A suite of test tools with functional requirements is also proposed for facilitating the implementation of test procedures. Conclusions:The potential test procedures for a congestion control algorithm are developed based on the simulation results of channel busy percentage and the GPS data generation algorithm. The test tools can examine the requirement compliance automatically and objectively. The required number of reference units should be further validated using real OBEs before implementing these potential test procedures.

A Distributed Congestion Control Strategy Using Harmonic Search Algorithm in Internet of Vehicles

“…Reference [8] proposed a control strategy based on a single-target Tabu Search algorithm in IoV (Internet of Vehicles). According to the minimized delay function, Tabu Search algorithm was applied to find the optimal value of transmission range and transmission rate.…”

Balancing Power and Rate Control for Improved Congestion Control in Cellular V2X Communication Environments

“…There are only a few works in the context of the DSRC communication environment. Hsu et al [28] proposed a testing methodology for the algorithm in the DSRC environment. Rostami et al [29] showed that the algorithm indeed controls the CBR within the targeted range, and the IPG within the guideline set by the National Highway Traffic Safety Administration (NHTSA) [30] in most cases.…”

“…The speeds of the vehicles are normally distributed, with the mean speed of 50 km/h and the deviation of 3 km/h. We use 300 bytes as the BSM size as recommended by Hsu et al [28]. The MCS index is 7, and the bandwidth is 10 MHz.…”

An Explicit Reservation-Augmented Resource Allocation Scheme for C-V2X Sidelink Mode 4

“…The modulation and target coding rate are QPSK and 0.5, respectively. Although the message set dictionary SAE J2735 states that four 190-byte BSMs with digested and a single 300-byte BSM with the full security credential to be iterated [5], we will assume constant 300-byte packets as in many previous work [10], [14], [15], [27], to focus more on the impacts of the explicit reservation. As to the inefficiency that the varying message sizes may cause on the resource use, the readers are referred to Molina-Masegosa and Gozalvez [11].…”

“…Finally, we omit the results for MCS 9, because it produces the identical qualitative results as MCS 7, only with lower packet delivery performances. We use 300 bytes as the BSM size as used in other works in the literature [10], [14], [15], [27]. Note that two different beacon sizes, such as prescribed by 3GPP TR 36.885 [4], more reselections may be necessary in case the resource allocation is only based on the smaller size, which could impact the performance [9].…”