Multicast delivery of file download services in 3G mobile networks with MBMS

This article investigates the efficient transmission of file download services to several users simultaneously in 3G mobile networks with HSDPA (High-Speed Downlink Packet Access) and MBMS (Multimedia Broadcast Multicast Services). HSDPA supports high speed point-to-point (p-t-p) transmissions (up to several Mb/s), whereas with MBMS the same content can be transmitted with a point-to-multipoint (p-t-m) connection to multiple users in a unidirectional fashion. Multicast delivery can be implemented through only p-t-p transmissions with HSDPA, a single p-t-m transmission with MBMS, or using both jointly in a hybrid approach by employing HSDPA for error repair of the MBMS p-t-m transmission. We investigate the optimum HSDPA and MBMS transmission configuration when they are used separately, and the trade-off between the initial MBMS file p-t-m transmission and the HSDPA error repair for the hybrid delivery. The approach of minimizing the transmission energy (product of the transmit power times the transmission time) to achieve a target file acquisition probability (percentage of users that successfully receive the file) has been adopted.