Mobile TV is the wireless transmission and reception of television content – video and voice – to platforms that are either moving or capable of moving. Mobile TV allows viewers to enjoy personalized, interactive television with content specifically adapted to the mobile medium. The features of mobility and personalized consumption distinguish mobile TV from traditional television services. The experience of viewing TV over mobile platforms differs in a variety of ways from traditional television viewing, most notably in the size of the viewing screen.
The technologies used to provide mobile TV services are digitally based,the terms unicast and multicast are used in the same way they are used for IPTV. That is, unicasting is transmission to a single subscriber, while multicasting sends content to multiple users. Although delivery of this type of content is technically feasible over today’s existing unicast networks such as 3G, these networks cannot support the volume and type of traffic required for a fully realized multimedia delivery service (many channels delivered on a mass market scale).
There are currently two main ways of delivering mobile TV. The first is via a two-way cellular network, and the second is through a one-way, dedicated broadcast network. Each approach has its own advantages and disadvantages. Delivery over an existing cellular network has the advantage of using an established infrastructure, inherently reducing deployment costs. At the same time, the operator has ready-made market access to current cellular subscribers, who can be induced to add mobile TV to the services they buy.
The main disadvantage of using cellular networks (2G or 3G) is that mobile TV competes with voice and data services for bandwidth, which can decrease the overall quality of the mobile operator’s services. The high data rates that mobile TV demands can severely tax an already capacity-limited cellular system. Also, one cannot assume that existing mobile handsets can receive mobile TV applications without major redesign and replacement. Issues such as screen size, received signal strength, battery power, and processing capability may well drive the mobile TV market to design hand-held receivers that provide a higher quality of voice and video than is available on most current cellular handsets.
Many 2G mobile service operators and most 3G mobile service providers are providing VOD or streaming video. These services are mainly unicast, with limited transmission capacity. They are built upon the underlying technologies used in the mobile cellular system itself – GSM, WCDMA, or CDMA2000. An example of a technology designed to work on a 3G network is Multimedia Broadcast Multicast Service (MBMS), a multicast distribution system that can operate in a unicast or multicast mode. Mobile TV services over existing GSM and WCDMA cellular networks operates in the 5 MHz WCDMA bandwidth, and it supports six parallel, real-time broadcast streaming services of 128 kbit/s each, per 5 MHz radio channel
Author: Nidhi Gupta