Adaptive Data Scheduling for Mobile Broadcast Carousel Services

Several mobile operators have now started "broadcast-like" services, which are based on the channel delivery model, known from classical broadcast services like radio and TV. Examples are goal notification for football fans (one club = one channel), news channels and mobile television in general. In order to efficiently support mobile broadcast services 3GPP has standardized multimedia broadcast multicast services (MBMS) for UMTS and GPRS in Release 6. The delivery of multicast/broadcast channels over capacity limited radio links requires intelligent scheduling mechanisms that make best use of the resources. The scheduler has to determine what content should be sent at which time in order to satisfy as many clients as possible. This work focuses on carousel based content delivery, which means periodical retransmission of each content. The paper investigates the performance and computational complexity of different scheduling algorithms applied for mobile multicast. The algorithms then are enhanced to fulfil the identified requirements of MBMS which are mainly adaptation to new contents, adaptation to network congestion and adaptation to the clients\´ demands. The simulation results are compared to conclude with recommendations for scheduling of mobile broadcast carousel services.