How does mobile TV work?

Probably, many people remember a small mobile TV, originally from the Soviet Union, which could be seen in cars and over which tourists were wildly pinned. Small portable televisions almost guaranteed a fuzzy image and interference even with slow motion, but were successful. Since then, a lot has changed - and now there are three options for receiving television data to the phone:

Analogue receiver

• Standard technology of the times of the USSR. A limited number of telephones with a retractable antenna and an analogue TV tuner are available.
• Consumes battery life quite substantially.
• Strong interference and distortion, worse when driving.

DVB-H

• A special network for TV broadcasting to mobile devices: we (in the country) would have to build and operate this one. Extremely limited selection of phone models with technology support.
• Battery life is most economically consumed.
• Reception is good when driving at speeds up to 150 kilometers per hour.
• Requires allocation of natural frequencies for broadcasting.

Streaming TV

• Uses a standard operator network. Coverage corresponds to the network. Easy to implement, supported by many phones, available for use in Russia.
• It consumes a lot of battery life: constant reception and complex post-processing.
• Mobility is very limited: the faster the movement, the worse the speed (network feature).

Analog receivers

Since the days of the USSR, much has been miniaturized, and phones with built-in TV tuners have appeared. By stretching out a small antenna, you can get a picture with constant noise, fuzzy geometry and unimaginable colors. And even though Samsung even has a model with a built-in analog TV tuner, key manufacturers of mobile devices do not massively implement this feature.

For mobile devices, there is a standard for digital broadcasting - DVB-T. If you need a clear image in motion, you need to not only work with another signal, but also have special software handlers "on board" the device.

DVB-H - Digital Broadcasting Standard for Mobile Devices

For mobiles, several special digital broadcasting standards have been created. This diversity is due to the fact that at the time the work began on mobile TV in various regions of the world, certain frequencies were already occupied, and most standards were developed as independent systems that required the construction of their own network and were tied to certain frequency spectra. In Russia, as in Europe, the DVB-H (digital video broadcasting - Handheld) format was chosen, in the USA and North America MediaFLO, 1seg (ISDB) was used in South America and Japan, and China and Korea with many neighbors made the choice in favor T-DMB.



As a result, many phones supporting digital mobile TV only understand national standards. All this affects both the cost of the chips and the desire of phone manufacturers to promote the new technology everywhere.
Formats have a lot in common - they are adapted for mobile devices. DVB-N is a logical continuation of the DVB-T (Digital Video Broadcasting - Terrestrial) standard with support for additional features, adapted for portable mobile devices with autonomous power.

DVB-H uses time slicing technology, with which IP datagrams are transmitted in small sets of packets at time intervals. Each of these sets can reach up to 2 Mbit of data, including a correction code in which for every 191 bits of useful data there are 64 bits of the correction code protected by the Reed-Solomon code. The receiving mobile device is included only in those time intervals during which data sets corresponding to the channel selected by the user are transmitted. During this short interval, data transmitted at high speed can be buffered by the receiving device, which can contain both downloaded data and a streaming video being played. This can significantly reduce power consumption and extends the duration of the mobile device.

Since December 2009, Moscow residents were able to receive the DVB-H signal from two broadcasters at once. Then these projects did not become commercial and did not go beyond the capital. Perhaps this is due to the fact that the Russian telecom giants saw another possibility of delivering a television picture to the subscriber's phone.

Streaming video over 3G

Unlike the variety of standards for mobile digital broadcasting, mobile operators around the world agreed that it is possible to organize mobile TV on the basis of existing 2G / 3G networks, as in this case, there is no need to use special equipment, most phones support streaming audio and video over packet networks.

Streaming TV, using streaming video technology, launched the majority of telecom operators in Russia and hundreds of operators around the world. The service is in demand mainly only in large cities. “The demand for television services via a mobile phone in Russia is still constrained by the need to buy expensive mobile equipment that supports this service,” PWC analysts said. However, individual solutions make it possible to provide the service on devices costing less than 3000 rubles, as well as on Nokia phones of the 40th and 60th series that have become “classics”. The geographically largest number of Streaming TV users is concentrated in the Central Federal District, Volga Federal District and the North-West Federal District. According to expert estimates, by the beginning of 2012 the number of service users in Russia reached about 2 million people.

The main protocol used for Streaming TV is RTSP. It is supported by the built-in media players of most phones, including Smartphones with Symbian and Android. RTSP is an application protocol designed for use in systems that work with multimedia data, and allows the client to remotely control the flow of data from the server, providing the ability to execute commands such as "Start", "Stop", as well as time access to files located on network attached storage. The average bitrate on the 3G network is about 170kbps, which allows you to watch programs in high quality. And on the EDGE network, the bitrate reaches an average of 80kbps, this allows you to watch news channels with satisfactory quality (for example, without a sharp change in pictures). Many Streaming TV platforms adapt the bit rate to the data transfer rate,

For users of iOS devices, the HLS protocol (HTTP Live Streaming) is used, and more recently Smooth Streaming Technology has been supported for devices with the latest Microsoft operating systems. Smooth Streaming uses the simple but powerful concept of delivering small pieces of content (usually in two seconds) and verifying that each one has the proper time and plays at the expected level of quality. If a fragment does not meet these requirements, the next fragment will be delivered at a lower level of quality. Conversely, when conditions allow, the quality of subsequent fragments will be at a higher level. This encoding mode allows you to broadcast several video bitrates at once,

Comparison of DVB-H and Streaming TV

The main problem of DVB-H technology is that the deployment of broadcasting throughout Russia would require a huge investment. And for Streaming TV, the coverage boundary coincides with the 3G / 2G network zone. Of course, watching videos in EDGE is not always comfortable on the big screen, but on the small one it’s quite possible.

Another enemy of DVB-H is the fact that you have to choose among 3 phones. Quite expensive, but not prestigious. Of course, in the case of the widespread distribution of DVB-H devices, there would be more, but now manufacturers have no incentive to bear the costs of mass-unsupported phone features.

Mobility DVB-H, which showed reliable reception at speeds up to 150 km / h in Moscow. With the mobility of 3G Streaming TV services, things are different. In practice, the transmission / reception speed depends on many factors and often turns out to be very far from theoretical limits. Two main factors are the quality of the terrain coverage with a 3G signal and the speed of the subscriber. Theoretically, in 3G, speeds of up to 2 Mbit / s should be available in separate locations allocated by the operator. Moreover, 2 Mbit / s are intended only for sedentary users whose movement speed is less than 3 km / h. The speed of the subscriber always reduces the speed of information transfer, often several times.

This is due to limitations in the very principle of the access system in 3G. For mobile objects, UMTS networks provide transmission speeds of up to 144 kbit / s (12-120 km / h) and up to 384 kbit / s (3-12 km / h), but in practice only about 20 kbit / s are obtained. Electric trains, metro, public transport, a car are still a luxury for Streaming TV, although it may be enough for 2-3 minutes to view downloaded data.

DVB-H is a truly mobile technology that provides the best quality service. But only if subscribers are ready to buy a special phone for her, and telecommunication operators invest millions of dollars in infrastructure. Both those and others were not ready for such decisive steps. As a result, the share of broadcast mobile TV around the world is declining, and the streaming - is increasing (according to forecasts, from 40% in 2011 to 53% in 2013).

Prospects

In the segment, analysts regularly forecast an annual steady increase in the subscriber base, which by 2016 should reach almost 6 million people, or 4% of cellular subscribers. Such forecasts are based, first of all, on the demand for mobile broadcasting of sporting events and the experience of the development of the Western European market.

Now Russian subscribers watch “mobile TV” on average three to five times a month for several minutes, however, on the days of significant sports and national holidays, there are significant surges in consumption. Practice shows that they watch TV on a phone either on the road or at home, for example in bed, when the big screen is not available, or if a person really does not want to miss a specific program, but does not have access to the TV. Therefore, you can forgive a service based on 3G for its voracity in relation to the battery charge. The possibilities of Television for Mobile as a classic advertising platform will also remain insignificant, as use of the service has been and will remain short-term. As a result, the likelihood that the subscriber will see the ad is already low, and given

It’s still a little early to talk about this, but it is assumed that in the future it will be possible to partially abandon the broadcasting network, characteristic of analogue times. It will be important for breaking news and sports, and the rest of the content will be provided to the user of choice.