# Connected Vehicles: Technology Review, State of the Art, Challenges and Opportunities
## 4 Challenges
### Over-the-Air (OTA) Updates  
Over-the-air (OTA) software updates are expected to be of great importance for CVs. Therefore, updates regarding the vehicle's performance or correctness of any malfunctions that may affect the embedded software equipped within the electronic control unit (ECU) can be conducted remotely. OTA will bring many benefits to the automotive industry including OEMs as well as drivers. According to IHS [133], one of these benefits is cost efficiency, as they forecast that savings due to OTA will reach up to USD 35 billion in 2022. This has motivated and derived many automotive makers to work towards endorsing OTA updates as a key element of their vehicles. OTA can provide new software update specifications to fleet vehicles that are currently on the roads. Furthermore, OTA offers new specifications to head units and tackles any vehicle-related issues. Hence, increasing revenues and decreasing the residual value losses by allowing vendors to provide add-on missing features. To leverage the OTA benefits, OEMs and suppliers are required to design end-to-end architectures and support modular in-vehicle software that require ease-of-upgrade functionality. Additionally, the infrastructure and backend systems should be designed to handle OTA updates that could allow for add-on features specific to the system design [15]. Although remote OTA software updates are considerably beneficial to the automotive industries, since it is fast and saves money and time as the driver can have the update any-time anywhere, it still raises and pertains to significant security issues. This is because the installation process of updating to the latest software on ECU will require full accessibility to in-vehicle communication networks [133; 134]. [PERSON] et al. [135] addressed the problem of decreasing the update time. One of the proposed solutions was to conduct parallel updates for ECUs that might reach up to 100 within an in-vehicle network. This solution has shown great impact in time reduction of the updates. However, there has been no optimal parallel scheduling algorithm that is able to utilize the full benefits of in-vehicle networks. Therefore, the authors presented a framework with high abstraction for an optimized parallel ECU software update scheduling. Hybrid and mixed-integer linear program scheduling algorithms were developed and tested against 20 ECUs in regards to both update and computing periods. Their evaluation shows that optimal parallelization can reduce the duration of reprogramming to 77% in comparison to sequential update, and their high abstraction model feature allows ease of adaptation to new vehicles' generations. Another important aspect of OTA software update is the possibility of software failure. In such cases, vehicles should be able to retrograde to older versions in an effort of reducing potential risks, which may occur as a consequence of the software update failure [136]. In [75], the authors present SecUp, a generic model for providing secure and reliable wireless software updates. SecUp makes use of IEEE 802.11 to connect vehicles and diagnostic devices in an efficient,fast, and dependable scheme. Wireless software updates feature including parallel and partial software updates and are enabled by SecUp for high efficiency along with adapting a secure mechanism to prevent attacks and malicious threats. Tesla makes use of wireless networks to provide remote updates from servers at the OEM location to vehicles. The use of a dedicated communication channel will not allow parallel concurrent installation on ECUs, which is considerably time consuming, as Tesla takes 20-90 min to complete the update [136]. GM unveiled a new _\"digital nerve system\"_ that will enable OTA software updates on all vehicles. This architecture will support 4.5 terabytes of data transfer per hour [137]. Most of the OTA software update research scope was conducted to address the security breaches caused due to complete access to in-vehicle communication networks during the updating process.