When a number of persons, e.g., a family or a group of friends, drive their vehicles for a trip together, they can form a fleet of vehicles and share their network resources during their trip. Let one member want to watch a video from the Internet. He may not have high resolution or video quality due to his limited 3G/3.5G bandwidth to the Internet. The cooperative video streaming scenario allows the requested member to ask other members of the same fleet to download video cooperatively. In other words, other members can help to download parts of the video from the Internet and then forward video data to the requested member hop by hop through the ad-hoc network. This work proposes the k-hop cooperative video streaming protocol using H.264/SVC over the hybrid vehicular networks which consist of 3G/3.5G cellular network and Dedicated Short-Range Communications (DSRC) ad-hoc network. In order to smooth video playback over the DSRC-based ad-hoc network, this work proposes: (1) one streaming task assignment scheme that schedules the streaming task to each member over the dynamic vehicular networks, and (2) packet forwarding strategies that decide the forwarding sequence of the buffered video data to the requested member hop by hop. Finally, we utilize the network simulator version 2 (NS2) to simulate the proposed protocol. Based on the simulation results, the proposed scheme can estimate the assignment interval adaptively and the playback priority first (PPF) strategy has the best performance for the k-hop video forwarding over the hybrid vehicular networks.

When a passenger in a vehicle wants to watch video during movement, he may request video through cellular network, e.g., 3G or 3.5G network. However, due to the characteristics of vehicular networks, the limited bandwidth of 3G/3.5G network is not enough to support high resolution or high video quality. In order to improve the quality of video playback, this vehicle, which is defined as requester in this paper, may try to ask other members of the same fleet to download video cooperatively. In other words, other members would download parts of requested video through their 3G/3.5G network individually and then forward video data hop by hop to the requester using the DSRC ad-hoc network. In order to smooth the DSRC ad-hoc network, we propose and discuss two k-hop packet forwarding schemes for the aforementioned cooperative video streaming over vehicular networks in this paper. Each intermediary node of the forwarding route must decide how to deliver buffered video data through the limited DSRC network. Finally, the NS2 simulation tool is adopted to evaluate the proposed schemes. Based on the simulation results, the Playback Priority First (PPF) scheme is performed better than the First-In First-Out (FIFO) scheme.

In this paper, we proposed a K-hop bandwidth aggregation scheme for member-based cooperative video streaming over the hybrid vehicular networks consisting of DSRC ad hoc network and 3G/3.5G cellular network. Each member in the same group is known to each other, e.g., they may be a family or a group of friends driving their sedans and they set out from the same position along the same path to the same destination during the journey. When a member in a vehicle wants to watch video during traveling, he will request video through 3G/3.5G network. However, the limited bandwidth of the 3G/3.5G network is not enough to support higher resolution or higher quality of downloading video. In order to enhance the quality of video playback, the member, who is called requester, in one vehicle can ask members, who are called helpers, of the same group in other vehicles to cooperatively download video through their 3G/3.5G networks and then forward their downloaded video to the requester through the DSRC ad hoc network. In order to select suitable members as helpers to download and forward the video and make video streaming more effectively to the requester over the DSRC Ad hoc vehicular network, how to select suitable helpers to forward the downloaded video hop-by-hop back to the requester needs to be resolved. In this paper, we proposed a K-hop bandwidth aggregation scheme to tackle the aforementioned problem. The performance results show that our proposed scheme can get better quality video than cooperative video streaming schemes without the deliberately designed K-hop bandwidth aggregation mechanism.