Mutimedia Communications Over Mobile Packet Networks.

This thesis describes several concepts associated with the transmission of multimedia services over mobile radio access networks. The error performance and traffic requirements of real-time video transmission over the General Packet Radio Services (GPRS) access network and its successor Enhanced-GPRS is examined. In view of this, video error resilience techniques which exploit channel prioritisation mechanisms are introduced with a view to increasing the robustness of received video sequences encoded with MPEG-4 to channel errors. These include stream prioritisation using unequal error protection and region-of-interest prioritisation for use in multiparty communications and streaming applications. A new forward-error correction scheme for EGPRS which uses iterative serially-concatenated convolutional-Reed Solomon codes is designed and is shown to significantly enhance the error performance for real-time services. A study of the use of backward error correction mechanisms when transmitting streaming multimedia services is carried out, and a new retransmission scheme is introduced to increase the capacity of the radio access network when supporting streaming services