# Blockchain Application in Internet of Vehicles: Challenges, Contributions and Current Limitations
## 4 Discussion
### Challenges of IoV-Assisted Smart Grid  
Internet of Vehicles is an emerging concept that is believed to help realize the vision of ITS within smart grids. Within this paradigm, the vehicles will be able to communicate with each other and with their environment: pedestrians, devices, traffic signs, etc. Thus, efficient road safety and global traffic efficiency applications will be developed and deployed, reducing traffic causalities [25]. Moreover, a massive amount of data will be introduced and outsourced to the cloud and edge storage from the vehicles as well as vehicular services that will be innovated for IoV. However, the integration with existing internet technologies to support the IoV paradigm opens up many challenges [3; 25] including security, privacy, trust, transparency, connectivity and performance. It is important to state, however, that the aforementioned challenges are common issues with the IoT paradigm and have been extensively researched [38; 39; 40; 41]. IoV, on the other hand, incorporates some unique characteristics compared to IoT, such as mobility and energy demand-response [17]. Thus, the IoV ecosystem might bring a number of novel challenges within smart grids. Such unique challenges of the IoV-assisted smart grids are presented in Figure 10 and described below:  
Figure 9: Blockchain application in the IoV—classification according to blockchain platform. **Challenge 1--High mobility:** Within IoV applications, all types of EVs are seen as fast-moving objects that often operate along roadways. Likewise, the operating speeds of the vehicles may differ, creating different mobility patterns, especially for manually driven vehicles [42]. As a result of the mobility of nodes in the IoV, it is difficult to correctly analyze the number of nodes that engage in the network. Furthermore, even if vehicles have the appropriate energy to utilize computational and communication resources when they connect with nearby objects, vehicles will struggle to maintain consistent connection due mainly to their variety and rapid mobility characteristics [17; 43], which would possibly bring additional challenges. One example is the difficulty of transmitting vehicles' critical data due to restricted transaction times, which are caused by the aforementioned mobility issues of the vehicles [44]. **Challenge 2--Complexity:** The IoV environment is built on a wireless communication network that supports a variety of wireless technologies. In this environment, vehicles communicate wirelessly with surrounding vehicles, humans and RSUs [45; 46]. Bluetooth and DSRC are examples of typical technologies that provide a variety of wireless network-related services (e.g., communication, message exchanges) in the IoV. Furthermore, the cars' network topologies vary due to their mobility, as discussed previously. As a result, the effects of network complexity on IoV scenarios are considerable. **Challenge 3--Reliability in critical applications:** In order to support mission-critical applications in the IoV (e.g., first responder communication and transportation systems), services with low communication latency and high reliability are required [47; 48; 49]. These latency-sensitive applications have propagation lengths that range from short to medium. As a result, the maximum time between the source and destination should be as short as possible for them. For instance, in emergency and safety-related applications, communication must be completed within a specific time frame in order to avoid potentially hazardous circumstances such as accidents [50]. Nonetheless, satisfying the service demand is difficult owing to the specific characteristics of the IoV, such as restricted wireless connection bandwidth, rapid vehicle mobility, quick data transfer and computing overhead. **Challenge 4--Scalability and Heterogeneity:** Considering the diverse nature of the IoV components, which include heterogeneous devices, protocols and platforms, smooth integration with cutting-edge information and communication technologies is required.