# A Survey of Vehicle to Everything (V2X) Testing
## 5 V2X Testing Methods
### Performance Testing  
Performance testing is an important mean to guarantee the latency and reliability requirements of V2X applications. It mainly includes end-to-end communication delay testing, packet delivery success rate testing, and parameter testing, such as signal strength under different channels. Through performance testing, testers can understand the effects of basic network communications, and further determine whether the performance of network communications can support V2X applications. [PERSON] and [PERSON] [73] implemented the 802.11p and 1609.3 protocols and tested the latency and packets loss in real filed. [PERSON] and [PERSON] [74] developed a simulation to test the routing throughput, end-to-end delay and packet delivery ratio of a protocol in several VANET scenarios. [PERSON] and [PERSON] [75] proposed a method for efficiently carrying out protocol testing for a set of designated node density distributions and their variations for VANET applications, network throughput, packet loss rates and etc. [PERSON] and [PERSON] [76] analyzes routing protocol on the aspect of packet delivery ratio, average end-toend delay and throughput using a NS-2 simulator. [PERSON] and [PERSON] [77] evaluated the packet delivery ratio, average end-to-end delay and bandwidth using a simulator based on NS2 and MOVE. [PERSON] and [PERSON] [78] testing the performance of the IEEE 802.11p standard for varying node density and data transfer rate by means of simulations  
Figure 5: Function Test System Architecture. (**a**) the V2X simulation platform directly generates application messages and sends them to the V2X communication module; (**b**) the V2X communication module generates corresponding application messages according to the simulation data from the GNSS simulator and the CAN bus simulator. using NS-3. [PERSON] and [PERSON] [79] studied the performance of DSRC based on Safety Pilot Model Deployment Data. [PERSON] and [PERSON] [80] evaluated the communication performance of Intersection Collision Warning(ICW) in field. [PERSON] and [PERSON] [81] investigated the performance of PC5-based and Uu-They are not the authors' surnames, please confirm.based LTE for crash warning application. Now we have built a performance test-bed for black-box testing. The architecture of the test-bed is shown in Figure 6. The test system consists of three parts, including UEs (also referred to as user equipment, including the UE under test and the peer UE for simulating the process of transmission), the evolved core network (i.e., the MME/S-GW in Figure 6), and the evolved UMTS terrestrial radio access network (E-UTRAN). The channel simulator is used to simulate wireless channel propagation over the PC5 communication link. Network testers or other testing tools (such as test software developed by the device provider) are responsible for managing the testing process and receiving testing data. The UEs can connect with the E-UTRAN system through the TD-LTE air interface (i.e., the Uu interface). The system can test sidelink basic transmission under Mode4 and Mode3, and IOT test of RRC protocol performance. Based on the timestamps and packet numbers in the packet header, the transmission delays and packet delivery success rates of the packets are measured. Most of the above works are mainly focused on the performance of a protocol using a simulator. However, equipment from different manufacturers may perform differently. So we need to test them using special testing methods and tools in the lab or filed. The lab testing could simulate a wide variety of performance testing environments, but it relies heavily on the model in simulators. The field testing is more realistic, but the extreme case is quite rare. Therefore, the performance testing meets the question of how to balance the lab testing with the field testing. The performance of V2X communication is also an important issue in the case of obstacles (such as buildings). To test performance in this scenario, modeling analysis and software simulation can be used [82; 83; 84; 85].