Multimedia communication with cluster computing and wireless WCDMA network

Distributed multimedia is a multidisciplinary area of research which involves networking, video/audio processing, storaging and high performance computing. Recent advances in video compression and networking technology has brought increasing attention to this area. Nevertheless, providing high-quality digital video in large scale remains a challenging task.; The primary focus of this dissertation is twofold: (1) We investigated a pure-software based parallel MPEG-2 decompression scheme. To achieve a high level of scalability, we proposed the data pipeline scheme based on a master/slave architecture. The proposed scheme is very efficient due to the low overhead in the master and slave nodes. Our experimental results showed that the proposed parallel algorithm can deliver a close-linear speedup for high quality compressed video. With a 100Mbps network, the 30-fps decompression frame rate can be approached using Linux cluster. With 680-Mbps SMP environment, we observed the 60-fps HDTV quality with 13 nodes. (2) The second topic of this dissertation addressed how multimedia applications can be effectively supported in the wireless wideband CDMA network. The major challenge lies in the fact that multimedia traffic usually demands high data-rate and low bit error, while the wireless network often experiences high bit error caused by multi-user interference over the air medium. Based on the observation that better channel quality could be obtained by using longer spreading codes, a new media access control (MAC) scheme was proposed such that the spreading code for each mobile is dynamically adjusted based on the network load and desired traffic QoS. With this new MAC protocol, the radio resource can be better utilized and more data traffic can be supported.; We further extend the dynamic spreading scheme to the multi-cell scenario to handle the mobile handover. Based on the system load of local and neighbor cells, the new handoff algorithm will decide when and what spreading factors should be used for a mobile during the handoff period. The algorithm also optimizes the assignment of spreading codes and mobile transmitting power such that the overall throughput can be maximized. The new handoff algorithm is also optimized to allow batch-processing for mobile requests to reduce the handoff delay at heavy traffic.