Mobile TV

A simple definition about what is Mobile TV could be: “The transmission of visual images of moving and stationary objects, generally with accompanying sound, as electromagnetic signals and the reconversion of received signals into visual images on any mobile or portable device (mobile phone, PDAs, etc.) in any location” (Mirics).

Mobile analog TV receiver have been on the market for years. They have not been a high success, which may be to the fact do not have any new additional feature over the normal television.

But digital Mobile TV is just television or this technology brings new services? This is the question that a lot of people may have. Mobile TV is a supplement to the normal television that have the capacity to support different services to the end-user handset terminal like Video-on-Demand TV (VoD), social TV platforms, interactivity (users can vote and take part in show games), etc. (Vodafone).

A mobile TV service requires significant content development and formatting to adapt offerings to the specifics of the mobile broadcast environment and market demand (Jordan & Schatz, 2006).

The objective of the industry is to develop new adding services, trying to develop the next generation of multi-media technology services in order to offer a new experience to enrich and satisfy mobile end-users. Video 1 shows the Siemens Mobile TV solutions.

Video 1

We can distinguish basically two television services, unicast and broadcast delivery.

Unicast (one-to-one) the user access personalized content (VoD), accessing it when and where he/she wants. Using a dedicated radio bearer per user allows an unlimited number of TV channels to be offered to a limited number of users. Is an interactive service, user makes a content query to the Mobile TV service provider (operator), so is necessary a bi-directional link between the end user and a video server is required to allows this interaction (Alcatel).

Broadcast (one to many) service is good to deliver the same content to lots of consumers at the same time. Using a common radio bearer for all users in the coverage area allows a limited number of TV channels to be offered to an unlimited number of users. That contributes in a most efficient use of channel capacity and a cost effective delivery method. The mass market can most optimally be achieved using this technology (Alcatel).

The following diagram (Blondeau O., 2007) shows the strength/weakness of five factors of both delivery services:

Diagram 1 (Blondeau, 2007)

There is a dilemma “Unicast VS Broadcast”, and this question appeals to mobile operators. Operators want to exploit their existing mobile network as much as possible, so they are interested in services, like unicast TV that can work in their current infrastructure (3G). But one of the important reasons why operators need to implement broadcast systems is to increase capacity and quality to cope with mass access to TV services, due the network limitations. The 3G network when must support more than a “few” users in a cell area the service rapidly breaks down because a lack of bandwidth (Broadcast Engineering, 2008). However, from a user-social point of view, broadcast is going in the wrong direction. Nowadays we live in the era of personalization, users want on-demand services. Clear examples of that demand are the success of Youtube and multimedia podcasts. Currently unicast services, typically in the form of streaming video and data delivered over a 3G network, are the most predominant type of mobile TV (Broadcast Engineering, 2008). But from a scalability point of view, switching to a broadcast technology makes sense.

So the solution to this dilemma is to merge the two approaches into a unified system such that the limitations of each are overcome by the primary advantage of the other. Unicast being used for interactive services on-demand content, and the broadcast service to support popular forms of content (sports, news, life events, etc) (Alcatel). In such a combined system, radio resources are not wasted.

References:

- Alcatel. (n.d.). Alcatel White Paper. Retrieved 5 2009, 20, from Unlimited Mobile TV for the Mass Market: http://www1.alcatel-lucent.com/com/en/appcontent/apl/S0206-MOBILE_TV-EN_tcm172-641791635.pdf?sess=e52f19db7d6cca388337e9f470a228fa
- Blondeau, O. (2007, 7 19). ANACOM & DigiTAG Mobile TV. Retrieved 5 2009, 20, from Broadcast/unicast complementarity for mobile TV and technology/spectrum issues: http://www.anacom.pt/streaming/olivieblondeau_apre.pdf?categoryId=247362&contentId=500329&field=ATTACHED_FILE
- Broadcast Engineering. (19 de 2 de 2008). Retrieved 5 2009,23 from Unicast versus broadcast mobile TV key dilemma for 2008 Mobile World Congress attendees: http://broadcastengineering.com/RF/unicast_versus_broadcast_mobile_0219/
- Jordan, N., & Schatz, R. (2006). IEEE Xplore. Retrieved 5 2009,13 from Broadcast Television Services Suited for Mobile Handheld Devices: http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F11153%2F35811%2F01698502.pdf&authDecision=-203