Thesis Work Presentation Multimedia Broadcast / Multicast Service from GERAN Physical Layer Point of View Thesis Work Presentation 17.01.2006 Henri Virta Supervisor: Prof. Sven-Gustav Häggman Instructor: M.Sc. Toni Majuri

Contents Background Objectives & Methodology Introduction to MBMS Competing technologies MBMS from PH Reselection point of view Summary and conclusions

Background information Multimedia Broadcast Multicast Service (MBMS) is a new feature specified in 3GPP Release-6 Method of delivering the same multimedia contents to several recipients in the service area Main idea behind the MBMS development is to provide multimedia contents simultaneously to several users, while preserving the network and radio resources

Objectives & Methodology Introduce the MBMS service Compare the MBMS service to other available solutions Analyze the MBMS service from GERAN/Physical Layer and specifically from PH reselection point of view Methodology Literary study based on 3GPP and ETSI specifications and change requests MBMS related conference papers and research articles Discussions within the Nokia organization on MBMS related issues

Introduction to MBMS (1/2) The main idea behind broadcast/multicast services is the possibility to save resources in the radio and core networks, by sharing the transmission path All MBMS services can be provided with cellular point-to-point (P-t-P) connections, but MBMS is more efficient if the same contents is delivered to several recipients in the same area The MBMS service is a solution for transmitting light video and audio clips, although it can also be used for real time streaming videos as well

Introduction to MBMS (2/2) MBMS bearer service offers two modes: Broadcast Mode: All users in the broadcast area can receive the broadcast service Multicast Mode: Only users who have subscribed to the specific multicast service and have joined the multicast group can receive the multicast service The subscribers can receive services, such as streaming video in a more economical manner. The Operator will control the MBMS service and content and can also control the QoS for the MBMS services For the Operator, MBMS will allow more efficient delivery and flexible pricing of existing point-to-point multimedia services

MBMS Procedures Broadcast mode Multicast mode

MBMS architecture MBMS architecture is designed so that the existing network elements could be re-used as efficiently as possible. A new component: Broadcast/Multicast Service Center (BM-SC) is needed in Core Network BM-SC serves as an entry point to content providers and is responsible for enabling the MBMS services to be provided to the end users via the Core and GERAN / UTRAN networks.

MBMS User Services The underlying MBMS technology is transparent to the end-user MBMS is planned for Low-to-Medium bit rate multimedia services in areas where several users are receiving the same service 3GPP specifies three different service types: Streaming: includes time synchronization File download: high reliability is required Carousel: a combination of streaming and file download. Typical carousel service uses still images and text that are updated periodically.

Other available solutions DVB-H (Digital Video Broadcast – Handheld) High bit rate multimedia services Efficient wide-area delivery No uplink access and other arrangements are needed 3G Point-to-Point Connections Low-to-high bit rate multimedia services Efficient only when delivering content to a few individual recipients in a geographical area Uplink easily accessible CBS (Cell Broadcast Service) Kind of a pioneer in mobile broadcast services Low bit rate messaging (SMS service)

Comparison to 3G P-t-P connection MBMS advantage over traditional P-t-P connections is clear when there are several recipients of the same multimedia data Resources can be spared in the Core Network as well as in the Radio Interface The advantage of the MBMS bearer service is greatest if several users are receiving the same service at the same time

Comparison to DVB-H DVB-H provides digital television to mobile handsets DVB-H is a solution to provide DVB-T(errestrial) programs to mobile users. The programs are sent to the mobiles in bursts by using IP data casting. Time slicing technique is used to achieve better battery saving percentage MPE-FEC error correction mechanism for additional robustness and mobility More efficient for delivering high bit rate multimedia services to wide areas, however uplink access not available MBMS has a possibility to limit transmissions only to areas populated by recipients DVB-H pilot programs already in use

MBMS Service Positioning Bearers competing with MBMS: 3G Point-to-Point bearers DVB-H multicasting MBMS vs. 3G Point-to-Point competition in sharing-type services MBMS vs. DVB-H competition in publishing-type services What is the overall feasibility of the MBMS service? What are the boundaries between competing bearers? Sharing (one-to-some) Service Coverage area User density 3G MBMS DVB-H Multicast Publishing (one-to-many) 3G P-t-P Boundary Area

MBMS from Reselection point of view (1/2) MBMS NEIGHBOURING CELL INFORMATION During MBMS the network may send MNCI messages, containing information about the neighbouring cells that are providing the same MBMS session. Delayed Reselection During MBMS If the mobile has not received the correct MNCI, the reselection is delayed for 1 second or until the correct MNCI is received Neighbour cell measurements If feedback is in use the mobile needs to report 6 strongest neighbour cells to the network in MBMS Ack/Nack message

MBMS from Reselection point of view (2/2) Reselection without the neighbour cell information The MS must first camp to the new cells control channels The MBMS service can be requested again from the new cell Fast reception resumption The MS moves directly to the new cells traffic channel (PDTCH) and continues to receive the MBMS session there. While receiving the MBMS session, the camping procedure is completed in the new cell by receiving the required (P)SI messages. SI2n A new system information message introduced in 3GPP Rel-6 Contains the necessary reselection parameters for the neighbour cells MBMS data transfer does not need to be interrupted for neighbour cell (P)SI reception

MBMS delayed reselection scheme A simplified flow chart of the delayed reselection scheme

Summary and Conclusions MBMS is a new bearer service that provides an efficient way of transmitting multimedia information to several users simultaneously MBMS is most efficient when several users are receiving the same service at the same time in a localized area MBMS will be competing with 3G P-t-P and DVB-H connections From reselection point of view, a big challenge will be the Fast reception resumption feature, since it changes the reselection and camping procedure Future Work: Further studies and analysis of the MBMS features, before starting any design or implementation for MBMS

Thank you!

Additional information 3GPP Specifications on MBMS: TS 22.146 Multimedia Broadcast/Multicast Service (MBMS) TS 22.246 Multimedia Broadcast/Multicast Service (MBMS) user services TS 23.246 MBMS Architecture and functional description TS 26.346 MBMS Protocols and codecs TS 43.246 Multimedia Broadcast Multicast Service (MBMS) in the GERAN Other useful 3GPP Specification 3GPP TS 45.008, Radio Access Network; Radio subsystem link control (Release 6) 3GPP TS 44.060 General Packet Radio Service (GPRS); Mobile Station (MS) – Base Station System (BSS) interface, Radio Link Control/Medium Access Control (RLC/MAC) protocol (Release 6) This material is available from the 3GPP homepage: www.3gpp.org

Backup information The MBMS service is analyzed from the Physical Layer (PH) point of view presented on the right hand side of the figure below