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1. INTRODUCTION

MBMS (Multimedia Broadcast/Multicast Service) is an IP datacast (IPDC) type of service that

can be offered via existing GSM and UMTS cellular networks. The infrastructure gives the

possibility to use an uplink channel for the interactions between the service and the user. This is

not a straightforward issue in usual broadcast networks, as for example conventional digital

television is only a one-way (unicast) system.

MBMS has been standardized in various groups of 3GPP (Third Generation Partnership Project),

and the first phase standards are to be finalized for UMTS release 6.

The service seems to be rather attractive, as quite a lot of operators, equipment manufacturers

and other representatives have participated in the standardization work. It can consequently be

assumed that there will be several services offered via MBMS in the near future.

MBMS is a solution for transferring light video and audio clips, although real streaming is also

possible via the system. For heavy duty streaming in a wide area for a large, concentrated

audience there are more suitable solutions such as DVB-H (Digital Video Broadcast, Handheld)

which is an extension to terrestrial digital television. Nevertheless, MBMS is a suitable method

also for mass communications.

The freezing target of the first version of MBMS has been set for Release 6. As Release 6 will be

ready by the 3rd quarter of 2004, practical network implementations may be expected by the 3rd

quarter of 2007, and the first functional mobile terminals supporting MBMS could be estimated

to be available by the third quarter of 2008.

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From 2008 onwards, the service will be introduced both in networks and terminals. According to

rough estimations, a total of 30 % of terminals and networks could support the service by the

year 2010.

1.1 . MULTIMEDIA BROADCAST MULTICAST SERVICE (MBMS)

It is a broadcasting service that can be offered via existing GSM and UTMS cellular networks.

The infrastructure offers an option to use an uplink channel for interaction between the service

and the user, which is not a straightforward issue in usual broadcast network, as for example

conventional digital television is only a one-way (unidirectional) system. MBMS uses multicast

distribution in the core network instead of point-to-point links for each end device.

MBMS will start to be rolled out in cellular networks during 2008 and gives the

gamesopportunity to broadcast TV, film, information and other media in these networks. MBMS

has the major benefits that the network infrastructure is already there for mobile network

operators and the deployment can be cost effective compared with building a new network for

the services. The broadcast capability enables to reach unlimited number of users with constantnetwork load. Further it also enables the possibility to broadcast information simultaneously to

many cellular subscribers for example emergency alerts.

1.2. TECHNICAL EXPLANATION

The MBMS feature is split into the MBMS Bearer Service and the MBMS User Service. The

MBMS Bearer Service includes a Multicast- and a Broadcast Mode. The MBMS Bearer

Service uses IP Multicast addresses for the IP flows. The advantage of the MBMS Bearer

Service compared to legacy UMTS bearer services (interactive, streaming, etc) is, that the

transmission resources in the core- and radio network are shared. One MBMS packet flow is

replicated by GGSN , SGSN and RNC s . MBMS may use an advanced counting scheme to

decide, whether or not zero, one or more dedicated (i.e. unicast) radio channels lead to a more


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efficient system usage than one common (i.e. broadcast) radio channel. UTRAN MBMS offers

up to 256kbit/s per MBMS Bearer Service and between 800kbit/s and 1.7Mbit/s per cell/band.

The actual cell capacity depends on the UE capabilities. GERAN MBMS offers between

32kbit/s and 128kbit/s. Up to 4 GSM Timeslot may be used for one MBMS bearer in downlink

direction. The actual data rate per Traffic Slot depends on network dimensioning.

The MBMS User Service is basically the MBMS Service Layer and offers a Streaming- and a

Download Delivery Method. The Streaming Delivery method can be used for continuous

transmissions like Mobile TV services. The Download Method is intended for "Download and

Play" services. To increase the transmission reliability, an application layer FEC code may be

used. Further, a file-repair service may be offered to complement the download delivery

method.MBMS has been standardized in various groups of 3GPP (Third Generation Partnership

Project). Practical network implementation is available from 2007, and the first functional

mobile terminals supporting MBMS are available from 2007.

MBMS is believed to be currently under active evaluation by Mobile Network Operators as a

means of delivering Mobile Television to the mass market. MBMS technologies, like TDtv are

now also in trials in the UK.

MBMS is a technology for broadcast of content over cellular networks to small terminals

(handsets) e.g. for mobile TV. MBMS utilizes point-to-multi-point connection, compared to

Unicast where each session has a separate connection. MBMS enables a wider number of

channels to be provided in the network since the combination of channels can be dynamically

adapted to the demand in each cell and can be multicast when several users demand the same

content.


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2. MBMS ARCHITECTURE

2.1. BROADCAST AND MULTICAST SERVICES

A broadcast service can be generalized to mean a unidirectional point-to-multipoint service in

which data is transmitted from a single source to multiple terminals (UE, user equipment) in the

associated broadcast service area. In the other words, broadcast services can be called push-type

services. On the other hand, a Multicast Service can be defined as a unidirectional point-to-

multipoint service in which data is transmitted from a single source to a multicast group in the

associated multicast service area. Only the users that are subscribed to the specific multicast

service and have joined the multicast group associated with the service can receive the Multicast

Services. As a difference, a Broadcast Service can be received without separate indication from

the customers. In practice, multicast users need a return channel for the interaction procedures in

order to be able to subscribe to the desired services.

MBMS is thus a unidirectional point-to-multipoint service in which data is transmitted from a

single source entity to a group of users in a specific area. As its name indicates, MBMS has two

modes in practice:broadcast mode and multicast mode.

MBMS provides a new method for transferring data for the number of users simultaneously. As a

general rule of the evolution path of GSM (Global System for Mobile communications) and

UMTS (Universal Mobile Telecommunications System) networks and terminals, backwards

compatibility issues apply also to MBMS. This means that MBMS will not interfere with already

existing GSM and UMTS services, and mobile terminals not supporting MBMS will work in

networks that offer MBMS for customers with MBMS capable terminals. The architectural

model of MBMS can be seen in Figure 1.


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2.2. REQUIREMENTS


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According to the specifications, there are some high level requirements that apply to MBMS

MBMS shall utilize the radio resources in an efficient manner.

MBMS data transfer shall be downlink only.

The reception of MBMS data blocks in PTM (point-to-multipoint) is not

guaranteed at the GERAN (GSM EDGE Radio Access Network) level. MBMS does not support

individual retransmission at the radio link layer, nor does it support retransmissions based on

feedback from individual subscribers at the radio level. This does not preclude the periodic

repetitions of MBMS contents based on operator or content provider scheduling or

retransmissions based on feed back at the application level.

Simultaneous reception of MBMS and non-MBMS services shall be possible and shall

depend upon MS capabilities.

Simultaneous transmission of more than one MBMS service shall be possible and the

reception shall depend upon MS capabilities.

MS controlled service based cell selection/reselection shall not be permitted.

A mechanism to enable the network to move MBMS subscribers, in an MBMS session,

between Radio Access technology (RAT) and cell is required.

Supported Quality Of Services (QoS) attributes shall be for MBMS multicast and

broadcast modes.

During MBMS data transmission it shall be possible to page a given mobile station

(MS), irrespective of the radio resource mode of operation.

MBMS notification procedure shall be used to indicate the start of MBMS data

transmission in the cell.

A mechanism shall be defined to enable the network to start the MBMS data transmission

for a multicast session in a cell if there is at least one user joined to multicast session in the cell.

A mechanism shall be defined to allow BSS to stop the MBMS data transmission for a

given multicast session in a cell that does not contain any MBMS MS joined to this multicast

session.


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2.3. Gmb

The Gmb reference point (Figure 1.) handles the broadcast multicast service center (BM-

SC) related signaling, which includes the user specific and bearer service messages.

MBMS bearer service specific Gmb signaling includes the following issues:

The GGSN establishes the MBMS bearer context and registers at BM-SC.

The GGSN (gateway GPRS support node) or the BM-SC releases the MBMS bearer context

and deregister the GGSN from the BM-SC.

The BM-SC indicates session start and stop to the GGSN including session attributes like Q0S

or MBMS service area.

2.3.1 User specific Gmb signaling includes:

The BM-SC authorizes the user specific MBMS multicast service activation at the GGSN.

The GGSN reports to the BM-SC the successful user specific MBMS multicast activation to

allow the BM-SC to synchronize the BM-SC UE MBMS context and charging with the MBMS

UE contexts in SGSN (serving GPRS support node) and GGSN.

The GGSN reports to the BM-SC when a user specific MBMS multicast service is released or

deactivated (e.g. when the radio contact is lost) to synchronize BM-SC UE MBMS contexts and

charging with the MBMS UE contexts in SGSN and GGSN.

The BM-SC initiates the deactivation of a user specific MBMS bearer service when the

MBMS user service is terminated.


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2.4. BM-SC

The BM-SC (broadcast multicast service center) includes functions for MBMS user service provisioning and delivery. It may serve as an entry point for content provider MBMS

transmissions, used to authorize and initiate MBMS Bearer Services within the PLMN, and can

be used to schedule and deliver MBMS transmissions.

The BM-SC is a functional entity, which must exist for each MBMS User Service. According to

the specifications, the following requirements apply to BM-SC:

The BM-SC shall be able to authenticate 3rd party content providers, providing content for

MBMS transmissions.

3rd party content providers may wish to initiate an MBMS transmission. In such cases, the

BM-SC shall be able to authorize content providers to transmit data over MBMS bearer services

depending on operator policy.

The BM-SC shall be able to verify the integrity of data received from content providers.

The BM-SC shall be able to generate charging records for content provider transmitted data.

The BM-SC shall be able to provide service announcements for multicast and broadcast

MBMS user services.

The BM-SC shall be able to provide the UE with media descriptions specifying the media to be

delivered as part of an MBMS user service (e.g. type of video and audio encoding).

The BM-SC shall be able to provide the UE with MBMS session descriptions specifying the

MBMS sessions to be delivered as part of an MBMS user service (e.g. multicast service

identification, addressing, time of transmission, etc.)


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The BM-SC shall be able to deliver media and session descriptions by means of service

announcements using IETF specified protocols over MBMS multicast and broadcast bearer

services.

The BM-SC should be able to accept content from external sources and transmit it using error

resilient schemes (e.g. specialized MBMS codecs).

The BM-SC might be used to schedule MBMS session transmissions, retrieve content from

external sources and provide this content using MBMS bearer services.

The BM-SC should be able to schedule MBMS session retransmissions, and label each MBMS

session with an MBMS Session Identifier to allow the UE to distinguish the MBMS session

retransmissions. These retransmissions are transparent to the RAN and MBMS user service.

2.5. UMTS TERMINALS

The following list identifies the most important User Equipment requirements :

The UE shall support functions for the activation/deactivation of the MBMS bearer service.

Once a particular MBMS bearer service is activated, no further explicit user request is required

to receive MBMS data although the user may be notified that data transfer is about to start.

The UE shall support security functions as appropriate for MBMS.

The UE should, depending on terminal capabilities, be able to receive MBMS user service

announcements, paging information (non MBMS specific) or support simultaneous services (for

example the user can originate or receive a call or send and receive messages while receiving

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MBMS video content). Reception of this paging or announcements may however, create losses

in the MBMS data reception. The MBMS user service should be able to cope with such losses.

Some UE depending upon terminal capability may be able to store MBMS data.

The MBMS session identifier contained in the notification to the UE shall enable the UE to

decide whether it needs to ignore the forthcoming transmission of MBMS session (e.g. because

the UE has already received this MBMS session).

2.6. OTHER MBMS RELATED COMPONENTS

The cell broadcast center (CBC) may be used to announce MBMS user services to the users.

The SGSN may use CAMEL (customized applications for mobile network enhanced logic) to

handle prepaid services, e.g. credit checking for on-line charging.

The BM-SC might use OSA-SCS (open service access) to interact with third parties.

3. FUNCTIONING OF MBMS


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As the term Mobile Broadcast/Multicast System indicates, there are two types of service

modes included in practical solutions: broadcast and multicast modes.

3.1. BROADCAST MODE

The broadcast mode refers to a unidirectional point-to-multipoint type of transmission of

multimedia data from a single source to all users that are found in a defined broadcast service

area. The broadcast mode uses radio resources efficiently, since the data is transmitted over a

common radio channel.

MBMS data transmission adapts to the most logical RAN capabilities, depending also on

the availability of radio resources. If needed, the bit rate of MBMS data may be varied in order to

optimize radio resources. Figure 3.1 shows the basic principle of the broadcast mode of a MBMS

network in order to broadcast several high data rate services within the defined broadcast service

area via a packet switched (PS) core network.

The broadcast service may include one or several successive broadcast sessions.

According to the specifications, a broad cast service might consists of a single on-going sessions

as a media stream, or may involve several intermittent sessions (Messages) over an extended

period of time.


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The broadcast mode is an enabler for broad casting of multimedia services. It differs,

though, from the traditional messaging services of GSM or UMTS, being more versatile.

Similarly as in cell broadcast functionality, users should be able to control the enabling or

disabling mode service (eg. The receiving of welcoming notes).

The broad cast mode cannot guarantee the error correction of the transmitted data by any

means. Nevertheless, the terminal may be able to recognize data loss that occurs during

reception.

3.1.1. BROADCAST PARADIGM

One-to-many communication

Strength: delivers same information to many users simultaneously

Weakness: no feedback channel for interaction

3.2. MULTICAST MODE

The difference between broad cast and multi cast modes is that the users do not need to

subscribe in each broad cast services separately, where as in multicast mode, the services can be

ordered separately. The subscription and group joining for the multicast mode service could be

done by mobile network operator, the user him/herself or a separate service provider. The current

understanding about the broadcast mode is that the services are not changed, where as the

multicast mode can provide services that are billed.

There are many similar requirements in multicast as in broadcast mode. As some

examples, the multicast mode allows the unidirectional point-to-multipoint transmission of

multimedia data within the multicast service that contain members of a multicast group.

A multicast service might consist of a single on-going session or may include several

simultaneous multicast sessions over an extended period of time.

One of the examples of the multicast mode service could be spot event result information,

which requires a subscription. Logically, the service could mean an extra charge for the


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subscriber, depending on the service providers billing strategies

.

As in broadcast mode, multicast services cannot be guaranteed over radio network.

Nevertheless, the reliable data transmission of applications and services can be enhanced using

proper higher layer methods for protecting the data.

3.2.1. MULTICAST PARADIGM

Addressing Groups Instead Of Single Hosts

IP Multicast is the efficient transmission of an IP datagram to a set of zero or more hosts

identified by a single IP destination address. (Deering, 1989)

Only one packet is send by the server to a group of receivers.


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Multicast Network (= IP overlay) cares about forwardingto registered hosts

-Packets are replicated only when necessary.

fig 3.3

3.3. CONTENT DELIVERY via EXISTING UNICAST BEARERS

fig 3.4


GGS

NSGSN

SGSN

nusers n unicast radio bearersnGTP-U tunnels

nflows

between

GGSN and

content server

THE NUMBER OF USERS n IS LIMITED BY AVAILABLE RESOURCES

Group of

Receivers Sender

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Here in the fig 3.4 represents the diagram showing content delivery via existing unicast

bearers. This consists of delivering services to each of the users. If there are n users then there

will be n flows between GGSN and content server. Then the SGSN transfers the n data to n

users. The next fig 3.5 shows content delivery via MBMS bearers .In this way of data

transmission there is only one flow between GGSN and content server.SGSN transfers common

radio source to multiple number users. In this it does do not depend upon the number of users it

only concentrates on multicasting the data to the users that are in specified multicast/broadcast

area. Here it takes the advantage of using the radio resources effectively as well as the users can

disable or enable the mode of services as they needed. This content delivery will takes place

even if there is one user or n number of users that is completely independent about the number of

users in MBMS specified area.


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3.4. CONTENT DELIVERY via MBMS BEARERS

fig 3.5


GGS

NSGSN

SGSN

nusers m< n radio bearers1GTP-U tunnelper SGSN

1flows

between

GGSN and

content server

INDEPENDENT OF NUMBER OF USERS n

Common

radio

resource

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4 .MBMS PROTOCOL STACK

The point-to-multipoint IP-based service is carried by the 3G air interface of W-CDMA

(UMTS Terrestrial Radio Access Network or UTRAN) or the 2.5G air interface of EDGE/GPRS

(GSM EDGE Radio Access Network or GERAN). The W-CDMA air interface provides bearer

rates up to 256 kb/s or greater, while the EDGE/GPRS air interface provides bearer rates up to

128 kb/s.

The MBMS protocol stack for streaming and download delivery. Streaming data such as

video streams, audio programs or timed text being encapsulated in RTP are transported over thestreaming delivery network. In this case, application layer FEC is applied on UDP flows, either

individually or on bundles of streams. Discrete objects such as still images, multimedia streams

encapsulated in file formats, or other binary data are transported using the FLUTE protocol (RFC

3926 1) when delivering content over MBMS bearers. More details on application layer FEC and

delivery methods will be presented later.

In both delivery services the resulting UDP flows are generally mapped on the MBMS IP

multicast bearers. The MBMS Bearer services reuse most of the legacy UMTS protocol stack in

the packet-switched domain. To avoid significant investments in network infrastructure and

handset chipsets, only minor modifications have been introduced in access network to support

MBMS.The new service relies on the 3G packet-based protocol stack.IP packets are received in

the 3G protocol stack in the Packet Data Convergence Protocol(PDCP)layer. Functions provided

in the Radio Link Layer (RLC) layer are for example segmentation and reassembly,

concatenation, padding, sequence numbering, reordering and out-of-sequence and duplication

detection. The Medium Access Control (MAC) layer maps and multiplexes the RLC-PDUs to

the transport channel and selects the transport format. The MAC layer and physical layer

appropriately adapt the RLC-PDU to the expected transmission conditions by applying, among

others, physical layer FEC channel coding, power and resource assignment, and modulation.


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Among others, an MBMS radio bearer defined by the physical layer FEC channel code

rate and the transmission time interval (TTI).The TTI is a transport channel specific and can be

selected from the set {10 ms, 20 ms, 40 ms, 80 ms} for MBMS.The higher TTI values are

supported by increasing the interleaving of the channel code and/or using longer codeword sizes

of channel code. This has the advantage of increasing time diversity but at the expense of longer

delays and more memory.


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4.1. FEC IN MBMS

In general, forward error correction (FEC) technologies protect data by encoding the

original source data at the sender such that redundant data is added. The FEC decoding algorithmthen allows the receiver to detect and possibly correct errors in the original data based solely on

the data that has been received. The error correction is "forward" in the sense that no feedback

from the receiver to the sender or further transmission by the sender is required. As observed, the

MBMS system applies FEC on two layers in a complementary way, namely on the physical layer

and on the application layer.

On the physical layer FEC encoding and decoding algorithms are implemented in

hardware as part of the W-CDMA or EDGE/GPRS air interface. Specifically for W-CDMA, the

MAC blocks are mapped to code blocks such that the maximum length of a code block does not

exceed 5114 bits. This limitation comes from the restrictions on complexity, memory and power

consumptions of Turbo decoders in handheld devices. After the Turbo coding is applied, the

resulting blocks are concatenated, interleaved and eventually rate matching is performed. Finally,

radio frames are transmitted every 10 ms using a chip-rate of 3.84Mcps and QPSK modulation.

The physical layer FEC code attempts to correct distortions that may have been induced

by noise, interference, multipath and other impairments over the wireless channel. Signal

variations on the time frame of a TTI shall be compensated by this processing. If the received

signal is too weak in a data block for the FEC decoding algorithm to correct, then the block is

unrecoverable. Generally any associated IP packet(s) is also entirely lost as reassembly is

infeasible. The block error rate (BLER or block erasure rate) then represents the failure rate of

the air interface FEC protection to recover the data blocks as partitioned at the physical layer.


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5. SERVICES AND APPLICATIONS

MBMS can be used as an enabler for various data streaming services. In practice MBMS

can be used for any kind of services, regardless of the content, as long as the limitations of the

data transmissions (data rate, possible errors etc) do not cause major problems to the quality

service. Compared to the traditional broadcast messaging solutions of eg GSM (cell broadcast,

CB), MBMS provides a multimedia type of transferring method with relatively high data rates

and considerably greater capacity than CB is capable of doing. Nevertheless, due to its

characteristics MBMS might not be an optimal solution for providing long-duration broadcastingstreams, eg complete videos or television programs.

MBMS service scenarios can be divided into three main groups:

Streaming (continuous data flow), download (and play) and carousel. The latter one

means the method to deliver contents repeating or, updating the transmission of data cyclically

(compared to text television).

Some of the identified applications for MBMS could be the following ones:-

New clips; the contents could be differentiated for separate new channels of MBMS areas

(main news, sports results, economics etc). The stream could be continuous, or it can be

ordered separately. The service can be realized eg:- by the text distribution, picture

delivery or low quality video.

Audio stream; as MBMS is offering a method to broadcast data stream for big audience,

the traditional radio type of broadcast with stereophonic sound is also feasible. Via

MBMS the more specialized solutions can be realized, as music clips and important voice


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notifications.

Localized services; there might be a local tourist information channel offered via

MBMS, showing the most important places, restaurants etc as a continuous stream.

Combined audio and picture/video clip service. This service applies to various

applications. Some examples are the advertisements, interactive television voting and

betting.

Video distribution services, either via streaming, carousal or downloads methods.

Content distribution in general; e.g. downloading individual files, http, video, audio or

combination of those. This can be used e.g. for the software updates of the user

equipment.

Game delivery; the games can be found in the main menu of the MBMS stream, and the

game can be downloaded to the mobile. In order to charge the game, the separate

interaction can be made, normally after the testing period of the game.

The charging of the multicast mode services could be carried out by basing on the events(similarly as normally done in multimedia messaging service), on the subscription (the duration

of the usage of the service), and on the content (e.g. the transferred amount of data or the type of

the service). Logically, the charging can be realized also as a combination of these methods.

As GSM and UMTS networks have been designed to handle the charging of the mobile

services already, e.g. SMS (short message service) or GPRS (general packet radio service) data

transmission can be used in order to subscribe and charge the services.


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In order to secure the MBMS transmission, MBMS provides the authentication, key

distribution and data protection for the multicast service. In addition to the normal security

related processes of the mobile network, the functionality of MBMS security is stored in MB-SC

or UE. MB-SC is responsible for generating and distributing the keys that are necessary for

multicast security to the UE5 and for applying the appropriate protection to data that is

transmitted as part of a multicast service. The BM-SC also provides the MBMS bearer

authorization for UE5 attempting to establish multicast bearer.

One of the important aspects in using MBMS services is to provide the means for the

users to find the offered services. Service discovery includes, thus, the main menu of the

available services, programs etc. (ESG, electronic services guide).


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6. ROLE OF MBMS

There are also other relevant services and systems that would suit to deliver the broadcast

type of traffic to the great number of audience simultaneously. DVB-H is an extension to the

already existing DVB-T (as well as to DVB-S and DVB-C) definitions. Depending on the

modulation, the DVB-H is capable of transferring around 5-1] Mb/s per carrier, which can be

further divided to several sub-channels. The practical number of the broadcast channels could be

e.g. 40-80, which provides the data rates of around 100-250 kb/s per sub-channel.

There are also other examples of the broadcasting services in the mobile environment.

One of the most concrete one is the Japanese ISDB-T (Terrestrial Integrated Services Digital

Broadcasting), which can be used both to fixed and mobile reception. There are already

prototypes of the hand-held terminals available in the markets since 2003.

The American version of the digital broadcasting system, ATSC (Advanced TelevisionSystems Committee), is not considered very suitable for the mobile environment since the

technical realization causes too much Doppler shifts in reception. There are ideas of extending

the ATSC to the mobile environment presented, but the backwards compatibility is not a

straightforward task with this technology.

Also WLAN (Wireless Local Area Network) could be used as a solution for the local

broadcasting purposes. One of the WLAN solution could be WiMax (IEEE 802.1 6a/e), although

its development is still under construction.


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Among next generation technologies, mobile TV will gain more and more momentum, as

mobile users get lots of useful content including information, films and other entertainment

related content on their mobiles. More than 120 mobile network operators worldwide have rolled

out commercial mobile TV services already, and consumers are becoming more discerning in

their demand.

6.1. POINT-TO-MULTIPOINT

At present, mobile TV content is streamed to mobile terminals/handsets in a point-to-

point connection, which is not cost-effective. A point-to-multipoint communication can

broadcast the same content to a large number of viewers. This is where MBMS or Mobile

Broadcast Multicast Service steps in to help the network operators. MBMS is standardized by

3GPP as part of the WCDMA evolution and will be available for both GSM/EDGE and

WCDMA connections.

In MBMS, with point-to-multipoint (PTM) paradigm, ideal for mobile TV, data packets

are simultaneously transmitted from a single source to multiple destinations. Unlike in the

unicast paradigm, where data packets are transmitted from a single source to a single person. The

MBMS technology allows a group of people interested in a particular program, in a particular

area, to watch the same program simultaneously, via both existing GSM as well as UMTS

networks. The MBMS technology supports HSPA in a situation where higher loads have to be

transmitted in dense areas, saving significant network capacity and enabling a more efficient use

of network resources, which ultimately results in cost saving for network operators.

Today, most mobile TV services worldwide are based on two-way point-to-point data

transmission using unicast. Once MBMS is introduced commercially, which is expected in this

year, the same content can be delivered to a mass number of terminals in a single transmission


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via multicast. But it doesn't mean that the introduction of MBMS will invalidate unicast. While

MBMS can be used for the most popular programs for a registered multicast group, unicast can

be used to deliver on-demand videos to the same group in a cost-effective way. This unique

unicast-MBMS model will help achieve personalization as well as delivering content to a mass

market.

The fig 6.1 shows the switching between point to point and point to multipoint. RNC

switches over between Point-to-Multipoint and Point-to-Point connections between Node B and

UEs in multicast mode so that each Node B is required less transmission power. In that case, the

RNC takes into account the residual time of data transmission and the number and the

distribution of UEs in a cell. The RNC counts the number of UEs joining a service in a cell. UEs

in connected mode are counted when joining and UEs in idle mode are counted by the responses

to periodical notifications


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6.2. THE MARKET

As MBMS requires only minor changes to the existing radio and core network protocols,

it reduces the implementation cost of infrastructures like terminals and networks. With its

capacity-boosting features, MBMS will stimulate the development of new and mobile mass-

media services, generating revenue opportunity for network operators and content providers. It

will enable service providers to offer cost-effective triple-play services for mobile handheld

devices over a common service and network infrastructure.

The number of mobile TV users in the Asia Pacific region is expected to be around 25

mn by the end of 2008. While India has already emerged as the fastest growing telecom market

in the world, MBMS and mobile TV will generate additional revenue stream for service

providers and content providers. Though the number of triple-play services users will be less

than simple voice and data users, the revenue generated by mobile TV will be very high as

mobile TV services will be costlier than the simple services.

Various stakeholders, including service providers, content providers, and advertisers

benefit from service fees, content fees, advertising and paid interactions such as games, videos,

and seasonal greetings. Before MBMS is introduced in the market, device manufacturers also

have to come up with low-power consuming cell phone batteries, essential to support data

intensive applications, and handsets for high memory capacity to support the high buffer

requirements of mobile TV.


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fig 6.2

The fig 6.2 shows the market positioning of MBMS. MBMS is a cost effective way to

realize multimedia broadcast / multicast services over their existing W-CDMA systems and a

barrier-free way to enter newly into the multimedia broadcast / multicast businesses from a

regulatory point of view.


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7. CONCLUSION

Mobile broadcast type of services might be quite attractive for customers that already

have adapted to the advantages of cellular systems. Not only the TV broadcast, but also a set of

solutions could be delivered via IPDC networks, taking into account the limitations of data rates

and QoS.

Even if there exist more and more enablers in the cellular environment, the important

issue is to be able to provide meaningful and attractive services for customers. MBMS seems to

be one of the enablers that could provide an interesting new tool for application developers in

order to offer new methods for customers to be able to utilize efficiently information society

services on the road.

As MBMS will not be reality until late 2007 and early 2008, i.e. the first terminals and

services will appear by that time, there is still quite long time to wait. The first DVB-H networks

might be seen already during 2006, but nevertheless, MBMS and DVB-H are not exclusive of

each other, as they are optimal in different environments.

Terminal evolution will be seen nearer practical network solutions, but the general trend

might be the development of sufficiently large displays. The Nokia 7700 represents a possible

approach for DVB-H terminals, although the first prototype versions will be used only for testing

and piloting purposes.

The other aspect to be considered will be the technical realization of the programs; as the

terminal screen will be relatively small and the data stream will not exceed a couple of hundred


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of kb/s in practical solutions, the content might have to be modified specifically for the mobile

environment. This means that the content will be edited from its original format to fit to the

screen more efficiently.

REFERENCES

R.Morshelli, B.bhattacharjee, M.A.March, A.Sreenivasan-Review of MBMS,

Barnes & Nobles MBMS, -Midwest book and manuscript studies

Nickel, Murrey, Faith,The MBMS

Websites:

http:// www.medialab.fi/workspace/mbmswhitepaper.pdf

http://www.en.wilkepedia.org/wik/multimedia_Broascast_Multicast_service

http://www.medialab.fi/workspace/mbmswhitepaper.pdfhttp://www.en.wilkepedia.org/wik/multimedia_Broascast_Multicast_servicehttp://www.medialab.fi/workspace/mbmswhitepaper.pdfhttp://www.en.wilkepedia.org/wik/multimedia_Broascast_Multicast_service

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ABSTRACT

The MBMS is a broadcasting service that can be offered via existing GSM and

UTMS cellular networks and it also offers an option to use an uplink channel for interaction

between the service and the user, which is not a common issue in the usual broadcast network,like conventional digital television which is only a one way(unidirectional ) system.MBMS uses

multicast distribution in the core network instead of point-to-point links for each end device.

Features of MBMS include Bearer Service and the User Service. Bearer services effectively

shares the core and radio resources. The flow one MBMS packet is replicated by GGSN,SGSN

and RNCs .It uses an advanced counting scheme to decide ,whether one or more dedicated radio

channels lead to more efficient system usage over one common radio channel. UTRAN MBMS

offers up to 256 kbit/sper Bearer service and between 800kbit/s and 1.7Mbit/s per cell/band. The

actual cell capacity depends on the UE capabilities. The MBMS has been standardized in various

groups of 3GPP.(third generation partnership project).

MBMS is a solution for transferring light video and audio clips, although real

streaming is also possible via the system. It is suitable method for mass communication. A total

of 30 % of terminals and networks could support the service by the year 2010.


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CONTENTS

1. INTRODUCTION 1

1.1. MULTIMEDIA BROADCAST MULTICAST SERVICES(MBMS). 2

1.2. TECHNICAL EXPLANATION. 2

2. MBMS ARCHITECTURE 4

2.1. BROADCAST AND MULTICAST SERVICES. 4

2.2. REQUIREMENTS. 6

2.3. Gmb. 7

2.3.1. User specific Gmb signaling. 7

2.4. BM-SC. 8

2.5. UMTS TERMINALS. 9

2.6. OTHER MBMS RELATED COMPONENTS. 10

3. FUNCTIONING OF MBMS 11

3.1. BROADCAST MODE. 11

3.1.1. BROADCAST PARADIGM. 12

3.2. MULTICAST MODE. 12

3.2.1. MULTICAST PARADIGM. 13

3.3 .CONTENT DELIVERY VIA EXISTING UNICAST BEARERS 14


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3.4 . CONTENT DELIVERY VIA MBMS BEARERS. 16

4. MBMS PROTOCOL STACK. 17

4.1. FEC IN MBMS 19

5. SERVICES AND APPLICATIONS 20

6. ROLE OF MBMS 23

6.1.POINT-TO-MULTIPOINT 24

6.2 .THE MARKET 26

7. CONCLUSION 28

REFERENCES


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MBMS

MULTIMEDIA BROADCAST

MULTICAST SERVICE

Submitted By

PRIYA N

S7 CS


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Roll. No. 7348

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