Video streaming on collaborated mobile devices over wireless mesh networks

Handheld mobile devices have created a new possibility for accessing video content over the wireless network. However, the limited resource, communication bandwidth, and mobility issues present challenges for effective delivery of the video data. On the other hand, presenting the video content with multiple collaborated mobile devices is now made possible by the pico projectors. A group of users can view and share the same video stream by placing their mobile device embedded with pico projectors in a tiled setup. With proper coordination between the devices, we can create a higher resolution display, and evenly distribute the power consumption and network traffic flow to the devices. In the first part of this dissertation, we discuss the issue of collaborating multiple devices and playing the same video content synchronized. Because the synchronization precision requirement is strict for playing multimedia content, we developed a scheme to synchronize multiple devices using only visual feedback. With the visual feedback from the embedded cameras, the mobile devices are able to find out the clock information of neighboring devices, and synchronize themselves autonomously. After the devices are synchronized, the mobile devices start to create a video stream over the wireless channel. To maximize the bandwidth, we propose a distributed and deterministic channel access function, which uses Latin squares to assign channel access slots and avoid potential packet collisions. Once the devices start moving and cause a handoff, the system will have to locate the new position of the devices and relay the data traffic to the new place. However, this process usually will interrupt the ongoing stream and disconnect the device from the network. The last part of this dissertation discusses the mobility issue and propose a solution that is also applicable to a large scale wireless network.