Transcript GERAN functionality walk-through TeliaSonera 15.10.2004

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
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
Contents
• Background
• Objectives & Methodology
• Introduction to MBMS
• Competing technologies
• MBMS from PH Reselection point of view
• Summary and conclusions
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
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
MBMS
P- t- P
Node B
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
Node B
17-01-2006
Henri Virta
Objectives & Methodology
• Objectives
 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
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
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
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
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
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
MBMS Procedures
Subscription
Service announcement
Service announcement
Joining
MBMS Broadcast mode bearer set-up
MBMS Multicast mode bearer set-up
Notification
In the service area
Notification
Data transfer
Data transfer
MBMS Broadcast mode bearer release
MBMS Multicast mode bearer release
Leaving
Multicast mode
Broadcast mode
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
In the service area
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.
GERAN
Content Provider
Packet Data Network
(e.g. Internet)
HLR
BSC
Content Provider
Iu/Gb
UTRAN
SGSN
Iu
GGSN
TPF
RNC
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
BM-SC
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.
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
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)
• Uplink easily accessible
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
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
3
SGSN
SGSN
GGSN
SGSN
GGSN
2
Core
Network
SGSN
1
P-t-P
Connection
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
MBMS
17-01-2006
Henri Virta
Core
Network
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
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
MBMS Service Positioning
• Bearers competing with MBMS:
• 3G Point-to-Point bearers
• DVB-H multicasting
Service Coverage area
• MBMS vs. 3G Point-to-Point
competition in sharing-type
services
DVB-H
Multicast
3G
P-t-P
Boundary
Area
Publishing
• MBMS vs. DVB-H competition
in publishing-type services
(one-to-many)
3G MBMS
User density
• What is the overall feasibility of
the MBMS service?
• What are the boundaries
between competing bearers?
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
Sharing
(one-to-some)
17-01-2006
Henri Virta
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
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
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
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
MBMS delayed reselection scheme
• A simplified flow chart of the delayed reselection scheme
SERVING CELL
MBMS
NEIGHBOURING
CELL
INFORMATION
received
Suitable
neighbour cell
found
Reselection is
triggered
MS is camped on
a suitable cell
receiving an
MBMS session
Yes
MBMS
reception
continues in the
new cells traffic
channel
No
MBMS
Reselection delay
timer started
PDTCH
MBMS
Reselection delay
timer timeout
No
MBMS
NEIGHBOURING
CELL
INFORMATION
received
NEW CELL
Campping to the
control channel
MS request the
MBMS service from
the new cell
(P)CCCH / (P)BCCH
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
NEW CELL
PDTCH
Yes
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
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
Thank you!
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
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
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta
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
ETSI
protocol stack
Control Plane
Data Plane
Applications
PDP_IF
IP
X.25
SNDCP
SM
RM
LLC
GMM
MM
RLC
MAC
RR
SNDCP
LLC
RLC
Physical layer
PH
MAC
DSP
PH
Multimedia Broadcast Multicast Service from GERAN Physical Layer point of view
17-01-2006
Henri Virta