Showing posts with label (e)MBMS. Show all posts
Showing posts with label (e)MBMS. Show all posts

Sunday 1 July 2007

Push-to-share over MBMS


During one of my MBMS trainings last month in Anritsu, i set everyone a task of defining a service based on MBMS. One of the services mentioned was Push to Talk (PTT) over MBMS.
Theoretically it should be possible to use MBMS for PTT. The voice in the UL is sent via a normal CS RAB. On the Downlink the data is Broadcast using MBMS. Since we would like the data to be sent to a particular set of users, it would be Multicasted rather than Broadcasted. Also this would mean that only the users in a particular Service Area will be able to receive this.
From operators point of view, Service Area should be big enough so that the user is seamlessly able to move a wide geographical area. At the same time it should not be too big because localised services (and adverts) can generate more revenue.
A bit of Googling and i came across some patents that are trying to do the same. Following is an extract from a patent Fresh Patents:
[0009] Use of a PoC application server together with a multimedia
broadcast/multicast service (MBMS) server for providing multicast transfer of
data in the downlink direction has been suggested. In the uplink direction PoC
typically uses Real Time Protocol (RTP) traffic unicast. In the uplink PoC
clients send speech data to the PoC application server, which then directs the
speech data packets either to the MBMS for the downlink leg to those
participants who receive the speech via multicast service or directly to those
recipients who prefer to receive via unicast directly from the PoC server. Use
of multicast in downlink direction improves the spectral efficiency in the case
of group communications with great number of participants. In addition, without
multicast it may not be possible to support large group sizes, if the
participants are located geographically in the close proximity.
Another was a patent on free patents:

0032] Herein, the MBMS service refers to a service for transmitting the same
multimedia data to a plurality of recipients through a wireless network. In this
case, the recipients share one radio channel, thereby saving radio transmission
resources. For example, the MBMS service includes a stock information service,
sport broadcast service, Push-to-Talk (PTT) service, and the like.
In fact C-Mobile is working on something similar. One of their documents highlight the limitations of the current MBMS architecture and suggests how we can improve the architecture in future for B3G Architecture.
My personal feeling is that till the Architecture is eveolved enough, PTT may not be very practical over MBMS but we should be able to use Push-to-share over MBMS. Some interesting short video clip or Breaking News Clip or maybe personal Valentine messages, etc can be shared using MBMS. It now needs to be seen if some operator picks on this idea and how soon.

Tuesday 26 June 2007

OMA seeks to ease mobile TV pain


The Open Mobile Alliance's recently-unveiled BCAST Enabler specification is designed to create a 'write once, run anywhere' environment' for broadcasters and other content providers. The spec - if widely adopted - could have significant implications for the concept of mobile TV 'roaming'.
In theory, it means broadcasters will be able to deploy their programming across the whole gamut of broadcast mobile TV platforms - DVB-H, DVB-SH, DMB, DAB-IP, ATSC-M/H etc - with little or no tweaking.
Because it works with any IP-based content delivery technology BCAST Enabler can also be used for the delivery of programming across cellular systems like 3GPP MBMS, 3GPP2 BCMCS and mobile unicast streaming systems, such as 3G streaming.

What benefits will OMA BCAST offer broadcasters and broadcast network operators?
• The specification enables broadcast-only mode for delivering services. It also allows broadcast-only terminals and free-to-air content with service and content protection capability.

• The specification is agnostic to access network meaning that the same service offering can be delivered over broadcast channel, interaction channel or both. Being agnostic to underlying architecture allows integration of the broadcast offering with operators or independent delivery over the interaction channel, which is controlled by broadcaster.

• Service interactivity is well specified and caters for broad range of services including interactive and direct feedback from viewers. Also, the service interactivity is not bound to the cellular channel – WLAN or a similar network can also be used. The use of the interaction channel allows personalization of services and service guides.

• The Service Guide enables the broadcaster to associate broadcast
programming with on-demand content. In addition, it supports both broadcast and on-demand delivery of the Service Guide itself.

What benefits will OMA BCAST offer terminal manufacturers?

• The Mobile TV Enabler specifies features for a common TV & video service layer that are currently not addressed by other specifications but still needed to ensure interoperability for large-scale terminal availability.

• Enables economies of scale by leveraging same technologies for both
broadcast and interactive channels. This means vendors can build an
economically viable terminal base that can be used by operators/carriers or broadcasters or jointly by both.

Saturday 2 June 2007

Mobile TV and MBMS will co exist

Someone brought my attention towards a Digitimes article where some people from Israel-based mobile chip designer Siano Mobile Silicon are talking about Mobile TV and MBMS. Some of the interesting points below.

Q: And what about multicast?

A: (Jashek) Again, multicast will end up placing a strain on the system bandwidth. The current MBMS (Multimedia Broadcast Multicast Service) capacity is limited to 2Mb/sec, while a broadcast system will provide bandwidth of 16-32Mb/sec, which is the bandwidth needed to support about 20 channels. Upgrading any existing cellular network so that it supports MBMS at 15-20Mbps (while not hurting the voice capabilities of the network) requires an investment that is by far larger than building a good mobile TV broadcast system.

We believe video-over-cellular services such as MBMS will continue to exist, but will gradually focus on “on demand” services, while actual mobile TV services will use a broadcast platform.
(Raab) Content will be broadcast to users, but users will be involved in the content, such as in programs that involve voting. And the way to create profits from this is to get more people involved in the service and bundling services to increase the amount of data that is going through the network, but in such a way that it does not strain the system.


Q: But who will build the broadcast infrastructure? Do you expect broadcasters and cellcos to be competitors or partners?

A: (Jashek) Most operators are facing the question of whether they should invest themselves or whether they should partner with a broadcaster to develop the infrastructure. In Italy, Telecom Italia Mobile (TIM) has deployed a mobile TV service where it is the service provider, even though Mediaset (a broadcaster) built the primary broadcast infrastructure. On the other hand, 3-Italia have made their own investment into a DVB-H network, and they enjoy a very good attach rate.

In the US, Qualcomm's subsidiary MediaFLO has solved this dilemma for the operators by building the network itself. The only thing Verizon or Cingular had to do was sign a contract with Qualcomm and offer the service.

Thus, different models exist. The relationship between broadcasters and cellcos will be one of the key issues affecting the success of mobile TV in the future. Most broadcasters already have the spectrum, as well as the content. They are currently using that for analog terrestrial TV, but in the future it will be used for digital mobile TV. However, cellcos already have a network that supports interactive programming. They also have an infrastructure in place for service and billing.

The question is how well can cellcos and broadcasters get along. What TIM has done, is take revenues from its mobile TV service and split it evenly with the broadcaster. In the future, we expect to see a similar type of model where broadcasters focus on broadcast services and operators focus on interacting with the customer.

Q: You mentioned that current analog TV spectrum will be allocated to mobile TV in the future. Can you add more color to that statement and explain how that will affect the development of the mobile TV market?

A: (Jashek) I should note that the development of mobile TV will go hand in hand with the migration of terrestrial analog TV to digital TV. For example, if you look at the DVB standard (DVB-T for terrestrial TV and DVB-H for mobile TV), which will be the DTV standard deployed in the most markets worldwide, currently about 30 countries have DVB-T networks, while another 30 will join in one to three years. Once the DVB-T networks are in place, you will see huge growth in DVB-H support because it does not take much investment to add DVB-H support to a DVB-T network.

Getting back to your specific question, a lot of countries have allocated spectrum to mobile TV on a temporary basis. Once governments start turning off their analog services in 2010, that spectrum will be allocated to mobile TV on a more permanent basis, and you will see a big jump in the size of the market.

We expect to see 120-130 million mobile TV users worldwide by 2010, with DVB-H being the number one platform. By 2012-2013 when more markets switch off their analog services, we expect to see 300-400 million people enjoying broadcast mobile TV.


Q: As you mentioned, DVB-H will be deployed in the most markets, however the global mobile TV market remains fragmented. Can you comment on the implications of how such a fragmented global market might affect the development of mobile TV?

A: (Raab) Obviously, with the huge expected size of the mobile TV market, a lot of different organizations would like to have a piece of the pie. Hence, a number of broadcast mobile TV technologies have been developed. Eventually, economy of scales will not allow more than about four technologies to survive in large volumes. It looks like the partitioning will be geographical.
(Jashek) DVB-H has its stronghold in Europe, where it was originally pushed by local players such as Nokia and Philips, and where DVB-T, the "mother" of DVB-H, has strong momentum. We have no doubt that DVB-H will dominate mobile TV in Europe, and DVB-T will also be supported on some hand-held devices. DVB-H is also expected to be the dominant standard in Southeast Asia – Taiwan, Singapore, Vietnam, Malaysia – and the Pacific Rim. In countries with vast rural areas, such as Russia or Canada, we expect that, around 2010-2011, DVB-H will be unified with DVB-SH (the satellite version of DVB-H). This will optimize the coverage with respect to the infrastructure investment required.


MediaFLO seems to be the winner in North America, although we would not be surprised if DVB-H will also be deployed there.

In Japan, as well as Brazil and a couple other South American countries, ISDB-T will dominate. And South Korea will continue with its T-DMB for some time, although being the only nation to have large-scale deployment of this standard will make it difficult for Korea to maintain it for many years. In China, the homegrown standard known as CMMB (S-TIMI) will be the main platform for mobile TV.

(Raab) Another thing to remember is that not only are the standards fragmented but so is spectrum support.

With the big picture being so unclear, device makers are looking for help to develop a solution that fits as many markets as possible. That’s why three years ago Siano came up with the concept of a multi-standard and multi-band mobile TV chip solution.

Our chips currently support the DVB-H/T, DAB and T-DMB standards, as well as covering the VHF, UHF, L1 (1450-1490MHz) and L2 (1660-1680MHz) spectrums. In addition, we will very soon have ISDB-T supported, while CMMB and MediaFLO are also on our roadmap. We are members of the CMMB working group, and the FLO Forum.


Q: Several mobile TV trials have been hampered by a lack of handset support, why is that?

A: (Raab) Handset makers need to digest and endorse a new technology – new types of antennas, receiver chips, software, etc. This is not easy. Some of the first few DVB-H phones were bulky, use antennae that were too long (making them unacceptable for most users), and have a reception sensitivity that was not that great.



The above diagram is from a Vodafone presentation ( Mobile TV from pure Broadcast to Interactivity, 19th Oct 2006 ). It shows how Mobile TV technologies will coexist with MBMS and the traditional unicast services

Monday 21 May 2007

MBMS Enhancements in Release 7

MBMS will be undergoing enhancements in Release 7 and this work item is seperate from E-MBMS or Enhanced MBMS which is part of 3GPP Long Term Evolution (LTE).

MBMS is being enhanced in Release 7 and IMS will be able to use MBMS transport. The advantage of this approach is:


  • MBMS reception is possible over IP accesses (e.g. I-WLAN)

  • Higher MBMS bit rate services possible (e.g. HDTV)

  • Support for adaptation of MBMS to the QoS resources provided by the access network(s)

  • MBMS services will be available regardless of access technologies and other services will be able to usse MBMS transport

This MBMS Enhancement is still under development and the following is being investigated:



  • Radio Interface Physical Layer: Introduction of new transmission schemes and advanced multi-antenna technologies

  • Layer 2 and 3: Signalling optimisations

  • UTRAN Architecture: Identify the most optimum architecture and functional splits between RAN network nodes

3GPP website lists some of the aims and objectives of these MBMS enhancements but theey do not look correct. They are copied from the LTE requirements documents. I will be revisiting this topic when more information is available