Technology

For mobile TV, there is no One Size Fits All…

Protect, Organize and Communicate Different countries and different operators all have their own regulations and customs to respect, which makes providing a simple, widespread solution virtually impossible.

Unicast versus Broadcast

  • Unicast This establishes a 1-2-1 relationship between the operator and the subscriber in order to deliver streamed content. Although other subscribers may receive the same content at the same time, each data stream is completely unique.

    Such a solution works fine where the network is not congested, but as Mobile TV service adoption increases, operators are looking to broadcast technologies to overcome the capacity problems of wireless networks.

     
  • Broadcast Broadcast implies the delivery of programs to multiple users simultaneously.

    It can handle an infinite number of users and has a limited impact on a network's quality of service. The greater the number of users in a particular cell, the more compelling the service, as content is sent only once over the radio while revenue is perceived many times.

The different main broadcast technologies

A number of technology platforms are currently available for multimedia broadcast services:

DVB-H (Digital Video Broadcasting - Handheld) is the extension of existing DVB-T to support terrestrial broadcasting of TV services to multiple handheld mobiles. It is optimized for low power consumption and handheld antenna. The existing TV broadcasting network is fully reusable with an upgrade to the DVB-H standard. Besides audiovisual and TV streams, DVB-H carries IP-based data including files, service notifications and auxiliary data streams for additional services.

 DVB-SH (Satellite Services for Portable) is a European satellite-based concept with direct-to-mobile transmission addressing coverage in rural areas and complemented with terrestrial repeaters to provide deep indoor coverage in urban areas.

MBMS (Multicast Broadcast Multimedia Services) could be used in two modes: for multicasting TV/multimedia services over a 3G network to participating mobiles, and to broadcast to all mobiles in the geographical area covered by the base station. MBMS enables:

- An optimization of radio resources: data is sent only in the cell where interested users are located.
- Data is sent in point-to-point (dedicated) mode to each user if the number of users in the cell is small.
- Data is sent in a point-to-multipoint mode when the number of users interested in the data increases to a level at which it is more advantageous to broadcast information than to have many dedicated radio channels. The threshold between point-to-point and point-to-multipoint distribution can be set dynamically by the operator.

DMB (Digital Media Broadcasting) is an evolution of DAB (Digital Audio Broadcasting) technology. The satellite-based implementation S-DMB is mainly in Asia and in Europe with focus on the terrestrial T-DMB.

Media FLO is based on the Forward Link Only (FLO) specification for "Terrestrial Mobile Multimedia Multicast“, a proprietary mobile TV technology of Qualcomm.

CMMB (China Multimedia Mobile Broadcasting) is a mobile television and multimedia standard developed and specified in China by the State Administration of Radio, Film and Television (SARFT). It is based on the Satellite and Terristrial Interactive Multiservice Infrastructure (STiMi), developed by TiMiTech, a company formed by the Chinese Academy of Broadcasting Science. It is similar to DVB-SH in many respects but differs in frequency bands and channel coding.

Access control and Content protection

When a TV service is deployed, you have to make sure that only users eligible for this service are able to consume it: Service and Content protection systems are used to prevent people who have not been officially granted from accessing TV services and restrict the use of TV contents.

There are two main types of TV service deployments, as seen previously: Unicast and Broadcast.

In Unicast context, the permanent point to point link between the end user and the TV distribution system usually makes it possible to perform the service protection server side. This is typically the case in classical 3G streaming TV.

In Broadcast context, no permanent point to point link is ensured between the TV distribution system and the end users. The same data is blindly sent to all users. In that kind of systems, there is no other choice than performing access control on client side. Two main families of technologies can be used in this context: Conditional Access System (CAS) and Digital Right Management (DRM).

Different technologies for access control and content protection

CAS systems usually involve a smart card or a secure element while DRM solution are software based.

Open Security Framework (OSF) is a set of DVB specifications that allow handset manufacturers to integrate a proprietary CAS application from different CAS vendors in handsets. OSF and similar CAS are extensively used today in Digital TV world. OSF has been chosen in the first deployments of DVB-H services in Italy and South Africa, and is being tested in many other countries.

The main CAS providers on the market today are Nagravision, Irdeto, Viaccess and NDS.

OMA BCAST Smartcard Profile (SCP) is a fully standardized CAS developed by the Mobile Telecom Industry. OMA BCAST is an open global specification for Broadcast TV services, designed to support multiple Broadcast technologies such as DVB-H/SH, MBMS (3G & 4G), IMB, BCMCS or MediaFlo. With SCP, the CAS client application is provided by the handset Manufacturer and Gemalto can provide the smart card application. This solution significantly reduces the cost and complexity of integrating a complete, multi-scheme mobile TV delivery solution for mobile device manufacturers and service providers.

DRM-Based Technologies
There is a wide variety of software solutions based on devices available today in the marketplace : Microsoft, Nokia, Adobe or standardized OMA DRM.

Both device-based and SIM-based approaches exist. Most operators request a SIM-based solution since it offers an unrivalled level of security and guarantees independence versus the handset.