What Is DVB H
DVB H stands for Digital Video Broadcasting For Handheld devices. These handheld devices can be Mobile and PDA (Personal Digital Assistance) etc. DVB H is a standard it is used to deliver digital TV services to mobile and PDA devices. It was published by ETSI (European Telecommunication Standards Institute ) in November 2004. DVB H is developed from DVB T.
DVB T stands for Digital Video Broadcasting Terrestrial. Many kind of modifications have been done in DVB T and then DVB H was developed. It was main concern behind development of DVB H that it should consume less battery of receiving devices like mobile.It should be mobile environment friendly. It should support single antenna reception.
Working Of DVB H
To better understand, a block diagram for DVB-H is shown below where green marks are modification of DVB H standard.
As shown above in the figure there is IP input signal which goes into the DVB H IP encapsulator. There are three part in DVB-H IP encapsulator MPE,MPE-FEC and Time Slicing. Where MPE-FEC and Time Slicing is two modified for DVB H standard.Then the output goes into the MUX.
In the MUX we are mixing traditional MPEG 2 TV service as well as DVB-H IP encapsulator. This mux gives TS (Transport Stream) as output.
This Transport Stream goes into the DVB T modulator to modulate the signal. DVB T modulator gives RF output.
Now this RF signal goes threw channel at receiver end.
This RF goes into the DVB T demodulator which demodulate the RF signal and provides Transport Stream as output. Now TS is decapsulate for DVB-H standard and provides IP output.
Difference Between DVBC DVBS DVBT DVBH
Time Slicing For DVB H
Time Slicing is used in DVB-H to reduce the power consumption of handheld devices like mobile and PDA. In time slicing the data is sent into the bursts. The data is sent at higher bit rate.The bursts contain the start timing of next bursts.Till this period elementary stream data is not transmitted. Because other elementary stream can use bandwidth for this.Thus our device stay active while it is receiving bursts. Statistical multiplexing is also used in this DVB-H standard.It reduces the bandwidth consumption or increases the number of services.
MPE-FEC For DVB H
MPE-FEC stands for Multi protocol Encapsulation-Forward Error Correction.It is used for improvement of C/N (Carrier To Noise Ratio).It is used to avoid the interference.It is next level of error correction.It calculate the parity data from the datagram. This parity data is send in MPE FEC sections with the datagram.At the receiving end after decoding we gets the datagram in good condition.Thus it provides better performance than DVB T.
Conclusion
DVB-H is a global standard. It transmit tv services to mobile devices and other handheld devices. It is modified from DVB-T. It is designed for mobile Tv and PDA. Many countries are using DVB-H Mobile Tv services. These countries are Austria,Namibia,India,Italy,Finland,Malaysia and Vietnam etc. DVB-H provides high data rate with low power consumption for receiving devices like mobile and PDA etc.
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