We developed a collaborative video download application, which allows several users to form a local group via peer-to-peer (P2P) links and collaboratively help one user in the group to download a high quality video. Cellular interface and P2P interface are simultaneously utilised in the application to guarantee quality of experience (QoE) when the cellular connection is disrupted. The application is based on Wi-Fi Direct technology and it exploits the service discovery function of the Wi-Fi Direct framework.Apart from the implementation itself, we also model collaborative video streaming over the cellular network under periodic cellular disconnections (e.g., the commuters experience poor Internet services when trains travel through tunnels). Our purpose is to exploit the gains of the collaborative download between users in the context of periodic disconnections and limited cellular downlink rate. We simulate several scenarios to find the requirements of the application that guarantee seamless and undisrupted playback.