Radio resource optimization for MBMS File transmissions

The 3GPP Multimedia Broadcast and Multicast Service (MBMS) for mobile networks enables the efficient distribution of files to a large audience using point-to-multipoint transmission. MBMS provides the so called file delivery service for this purpose. Residual errors are not tolerable in the received data of the file. Application Layer Forward Error Correction (AL-FEC) and transmit power need to be configured to yield low residual errors after the initial file transmission. In order to recover also the residual packet errors a repair phase is executed in which terminals can request additional AL-FEC encoded packets. The paper assumes repair packets are transmitted using HSDPA and evaluates the overall system efficiency, balancing ALFEC, transmit power, packet size and the amount of missing data that has to be retransmitted in the repair phase.