Power efficient radio bearer selection in MBMS multicast mode

Multimedia Broadcast Multicast Services (MBMS) was introduced in Third Generation Partnership Project (3GPP) Release 6 in order to address the need for the efficient usage of the expensive radio resources. The goal of this effort is to support downlink streaming and download-and-play type services to large groups of users. From the radio perspective, MBMS includes point-to-point (PtP) and point-to-multipoint (PtM) modes. The fact that Node B's transmission power is a limited resource and must be shared among all MBMS users in a cell indicates the need for power control during an MBMS service. Consequently, the analysis of the transmitted power plays a fundamental role in the planning and optimization process of Universal Mobile Telecommunications System (UMTS) radio access networks. In this paper we investigate the factors that affect the Node B's transmission power levels during an MBMS session, such as, cell deployment, propagation models, users' distributions and mobility issues. To this direction, the transport channels in the downlink, currently existing in UMTS which could be used to transmit the multicast data over the UMTS Terrestrial RadioAccess Network (UTRAN) interfaces are examined.