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DVB-H: Digital Broadcast Services toHandheld Devices

Zafar Mehmood, Safar Ali,Waqas Ayub

Comsats institute of informationtechnology

Chak shahzad campusIslamabad.

This paper will give a review on the project with

the title mentioned above i-e DVB-H (Digital VideoBroadcast To Handheld Devices). The dvbhtechnology is based on its previous version knownas DVB-T (Digital video Broadcast on Terrestrial

Digital TV). This project will enable us to havedigital TV broadcast on our mobile devices. We willbe implementing our project on simulink a part ofmatlab.

I. Introduction:The DVB-H project research work was

started on the basis of DVB-T its earlier mode inthe year 1998. While in the year 2000 the EU(European Union) make the project authenticatedby saying that digital TV reception is possible onmobile devices. In November, 2004 the ETSI(European Telecommunications standards

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institute) published standards for DVB-H. The DVB-H services are on air in different countries aroundthe world and more to come in future.

II. DVB-H SYSTEM AND STANDARDS: The DVB-H system is based on the previousversion of its technology known as DVB-T. The

physical layer of both DVB-H and DVB-T issame with some blocks being replaced innewer version i.e. DVB-H. Here we will discusssome of its main blocks working. The mainelement of the physical layer of DVB-H is TimeSlicing and FEC (Forward Error Correction)coding. Now Time slicing comes the first in theprocess so while discussing it the time slicing

basically reduces the average power by 90 to95% at the receiver end and also facilitatesthe system for smooth frequency handoverwhen the user leaves one service area andenters into another service.

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FEC (Forward Error Correction) for

multiprotocol encapsulated (MPE-FEC) givesan improvement in carrier to noise ratio (C/N)and helps in Doppler performance andmoreover improves tolerance to impulseinterference. The payload of DVB-H is IP-datagrams and other network datagrams arealso encapsulated in MPE section. The audioand video streams used for DVB-T does not

suit the DVB-H transmission so the MPEG-2 isreplaced with H.264/AVC or other highefficiency video coding standards.

Figure 1: Conceptual structure of DVB-Hreceiver

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The physical layer being shown in figure 2 hasfurther four more extensions while discussingthose first comes the turn of TPS (TransmitterParameter Signaling) having basic function totransmit the bits, secondly a 4k OFDM (OrthogonalFrequency Division multiplexing) having basicfunction of mobility and controlling the SFN (Single

Frequency Network) which enables us to receivesignals through single antenna in a very high bitrate reducing complexities in transmission andreception. The 4k mode is also used for thepurpose of the interleaving which facilitates us inerror correction. The 4k mode also producestolerance to impulse noise. The last component isthe channel for the transmission. The channel wewill be using is a 5-MHz channel bandwidth while inAmerica they use a channel bandwidth of 1.7 GHz.An example based figure 2 is being shown inwhich, both traditional MPEG-2 services are timesliced and are carried over the same multiplex.

Figure 2

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III.

Simulations:Here below there is some comparisons

we did on simulink between DVB-H and DVB-T

the simulations results were stored. These

results are for 16 QAM having code rate of 2/3

mode. The scheme of modulation allowed

transmission bit rate of 5 to 14Mb/s from 500

km to 130 km.

Figure 3

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IV. Conclusions :

The new DVB-H standard is on the way to

change the current digital TV standards from

fixed mode to that of mobile versions. The

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DVB-H has proven to be successful during

laboratory tests and field tests. The additional

error correction and the concept of

interleaving have made it more reliable in itstransmission and reception modes. The time

slicing has made this project to a state of

reality. The several pilots networks are

running in various parts of the world and the

user terminals takes place by several

manufacturers.

V. Future works: Transmit diversity is a promising techniquefor mobiletelevision based on the DVBH standard.Simulations confirm that transmission gain can beachieved. However, more detailed tests andmeasurements are required for practicalperformance evaluation especially in the urban

environment and inside buildings.

VI. References:

[1] Digital video broadcasting (DVB);transmission system for handheld terminals (DVB-H), ETSI EN 302 304 V1.1.1 (2004-11), European

Telecommunications Standards Institute.[2] Digital video broadcasting (DVB); DVBspecification for dataBroadcasting, ETSI EN 301 192 V1.4.1 (2004-11),European Telecommunications Standards Institute.

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[3] Digital video broadcasting (DVB); Specificationfor service information (SI) in DVB systems, ETSIEN 300 468 V1.6.1 (2004-11),

European Telecommunications Standards

Institute.