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

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

3. 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

4. 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

5. 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

6. 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

7. MBMS Procedures
Broadcast mode
Multicast mode

8. 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.

9. 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.

10. 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)

11. 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

12. 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

13. 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

14. 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

15. 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

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

17. 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

18. Thank you!

19. Additional information
3GPP Specifications on MBMS:
TS Multimedia Broadcast/Multicast Service (MBMS)
TS Multimedia Broadcast/Multicast Service (MBMS) user services
TS MBMS Architecture and functional description
TS MBMS Protocols and codecs
TS Multimedia Broadcast Multicast Service (MBMS) in the GERAN
Other useful 3GPP Specification
3GPP TS , Radio Access Network; Radio subsystem link control (Release 6)
3GPP TS 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:

20. 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