Time-frequency slicing

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The Time-Frequency Slicing ( English , abbreviated as "TFS") is a digital video broadcasting transmission method of the Broadcast Technology

TFS with 4 channels and with 5 services (programs)

Procedure

With the time frequency slicing method, several broadcast channels are combined into one channel in order to increase the robustness and effectiveness of DVB-T distribution. The individual TV services are distributed to all available channels. The different propagation conditions of the respective radio channels are used to increase the system properties - for example, antenna diagrams and antenna gain show a certain frequency dependency and thus dependence on the respective radio channel. The fluctuations between the channels are caused by frequency-dependent fading and adjacent channel interference. With the help of this method, all programs and services can be received in the entire reception area, which is larger than the coverage area of ​​the worst channel. There is greater gain in static multiplexing through a wider transmission channel. With static multiplexing, individual television programs or services do not receive a constant data rate . The data rate of the channel is adjusted depending on the content. For example, channels with few changes (e.g. still images or inserts) receive a lower data rate than programs that contain fast image changes.

advantages

Studies have shown that a combination of four to six radio channels can achieve a capacity increase of 20 to 25 percent using the time frequency method. When transmitting high-definition television and ultra-high-definition television programs (UHDTV programs), additional gains in data rates of 20 to 25 percent can be achieved. The higher transmission capacities can either be used for the introduction of new services or can improve the reception of existing programs by using more robust transmission parameters. With the help of TFS, the distribution of UHDTV via aerial television can be facilitated.

disadvantage

To implement TFS, all receivers in the reception area must be equipped with new TFS-compatible receivers in order to receive a TFS-processed signal . Even if there are differences in the size of the coverage areas of the individual channels, TFS cannot be used. Switching to this system is also difficult, as at least 2 free channels are required. It is often difficult to own these and therefore a switch would not be possible without broadcast interruptions for the viewer. For example in the UK there are 3 public and 3 private channels. Two TFS channels could be generated from this, since both the operators and the levels of supply are different. Time-frequency slicing is only effective from 4 channels.

application

Time-frequency slicing is so far only a concept and is not yet in use. The plan was to use the TFS method with DVB-T2 , but it was not implemented. It is planned to use time-frequency slicing in the further development of DVB-T2.

Individual evidence

  1. ↑ a b c d An Introduction to Time-Frequency Slicing. (PDF) EBU, February 2016, accessed on May 9, 2017 (English).
  2. ↑ Peter Dehn: Statistical multiplex - what is it? In: dehnmedia.de. Retrieved May 9, 2017 .
  3. ^ Mats Ek Technical Director: Time Frequency Slicing. (No longer available online.) December 3, 2014, formerly in the original ; accessed on May 9, 2017 (English).  ( Page no longer available , search in web archives )@1@ 2Template: Dead Link / www.progira.com
  4. ↑ Jordi J. Gimenez, Erik Stare, Staffan Bergsmark, David Gomez-Barquero: Time Frequency Slicing for Future Digital Terrestrial Broadcasting Networks - Abstract. June 2014, accessed on May 9, 2017 .