| With the advances in wireless communications technologies, more and more mobile devices are multi-homed, i.e., mobile devices have the capability to connect to heterogeneous wireless networks at the same time. Based on this concept, we propose a general information dissemination and recovery framework, which we call Cooperative Peer-to-Peer Repair (CPR). With CPR, users can first receive information through their Wireless Wide Area Network (WWAN) interfaces, and then utilize their Wireless Local Area Network (WLAN) interfaces to organize themselves into a peer-to-peer network and help each other to recover the packets.;The dissertation presents our approach of utilizing the CPR framework to improve multicast/broadcast video quality in wireless networks. Our work consists of the following four interdependent components. (1) We proposed to combine Network Coding (NC) with CPR (NC-CPR) to exploit the broadcast nature of wireless transmissions and achieved improved CPR performance. (2) Because of the dependency structure of video packets, we showed that by imposing structures on NC, CPR can be optimized for broadcast video in a rate-distortion manner so that more important video packets were repaired with higher probabilities and further performance improvement can be achieved over plain NC-CPR. (3) With the strength of CPR, we then proposed to perform CPR-aware rate-distortion optimized Joint Source/Channel Coding (JSCC) of WWAN video multicast targeting an entire CPR collective of multi-homed ad-hoc peers in the same multicast group. Because of CPR, a packet can be transmitted from the source to a peer either via WWAN directly, or via local repairs exploiting neighboring peers' WLAN links; the overall more general transmission condition means a clever JSCC scheme can now allocate more bits to source coding without suffering more packet losses, leading to higher video quality. (4) Lastly, we moved our focus from exploiting the strength of CPR, to ensuring successful packet reception in the CPR framework. Our approach involved optimal channel allocation between wireless transmitters and receivers, which we call Channel Pool Management (CPM). With CPM, one can locate the best channel for communication and seamlessly direct traffic to that channel, which greatly improves video communication quality. |
