## 3 IoV Enpowered IVI in 3G and 4G
### IVI Collaborative Mode
#### 4.2.2 Mobile Center for Resource Complementarity  
Figure 3 presents the Computing-Distribution-Collaboration (CDC) mode in terms of vehicle resource complementarity, which can be divided into three layers: shared computing based on vehicle-mounted hardware and software, cache-aided IVI sharing, and generated IVI content delivery for the intra-connection and inter-connection. Utilizing distributed vehicle proxy servers, the content  
delivery network can be moved into vehicle platforms and enables IVI users to access the multimedia contents from surrounding cars. In the CDC mode, the vehicle integrates the function of roadside and on-broad units as a mobile center for resource complementarity. Through the vehicle-centered scheme, the MaaS will further approach to target users and respond to their requirements immediately. The detailed illustrations about the CDC mode are as follows:  
**Shared computing:** Nowadays, intelligent vehicles have been equipped with powerful processing modules (e.g., CPU, GPU, NPU, and TPU) and software tools (e.g., OS and specific applications). Supported by 5G-V2X and intelligent techniques, the ability of on-broad units increases constantly. However, due to the price and the positioning among the automobile models, the capabilities of signal processing are different. In order to deal with this issue, the shared computing architecture by resource complementarity among inter-vehicle is utilized to finish the common real-time tasks, such as rendering, clips and retrieval for ultra high definition (UHD) videos. When a car is unable to meet its own processing needs of streaming service, except for roadside units, nearby vehicles with strong processing capacities and abundant computing resources will offer assistance. Inspired by this idea, new revenue modes exploiting the remaining vehicle hardware and software resources are created, which will improve the marginal utility of the vehicle. **Cache-aided content sharing:** Initially, the deployment of cloud architecture in transport scenarios facilitates the inter-connection and intra-connection via virtual configurations. However, it may cause network congestion and high latency for the central cloud. Considering the raw data generated by vehicles are up to 4 terabytes per day [84] and the transmission rate of the UHD video, the capability of mobile backhaul and core network cannot bear the huge data flows between vehicles and cloud platform in rush hours. The vehicle caching technique can be utilized to cope with the large amount of semi-structured or unstructured data with less delay and congestion. The implementation method is: if IVI users need the video streaming service but the required contents are not included in its cache or local storage space, the signal of content request will be released to the nearby vehicles, which start to retrieval whether its own cache has this resource or not. Then, eligible vehicles feedback the acknowledgement signal to notify the required vehicle, which will select the optimal vehicle to establish the connection and receive the streaming media according to a certain selection strategy (e.g., distance, channel condition, etc.). In this way, the overall cache hit rate will be improved and IVI users' requests can be quickly responded even in the high density traffic area. **Generated IVI content deliver:** As a powerful edge server, the intelligent connected vehicle could deliver sensor-generated contents as quickly as possible according to the end-to-end requirement. The deliver path can be categorized into two types: intra-connection and inter-connection in a heterogeneous network. The high-efficient resource allocation algorithm in vehicle-mounted scenarios is important to efficiently distribute IVI contents (e.g., text, document, image, UHD video, and living streaming) from server to IVI users in a proper way. For the intra-connection between V2X in neighboring areas, the common-interest user pair is established to share contents via device-to-device (D2D) links.