[SOLVED] do we use pilot carrier in Digital Communication ?

[furqanaliali]

Hello all,
Do we use pilot carrier in Digital Communication as we use in Analog Communication ?, if Yes, can u please guide me from where can i read literature about pilot carriers in Digital Communication.

Thank you in advance.

 

[Mityan]

Pilot subcarriers in OFDM for example. But this subcarriers also transmit data, they are not a standalone tones. But this data is known, not random.

 

[zorro]

Hi furqanaliali,

Do we use pilot carrier in Digital Communication as we use in Analog Communication ?

In some Analog Communications systems, pilot is included in transmission in order to allow or facililitate carrier recovery at the receiver, i.e. generation of a local oscillator with the correct frequency and phase needed for correct demodulation.
In Digital Communications this function is not normally needed because carrier recovery can be readily performed from the data bearing signal.
Regards

Z

 

[Shug]

Not sure what pilots are used for in analog communication, but they are regularly used in digital communication for the purposes of channel estimation, timing/frequency offset estimation, sampling clock offset estimation, etc. A pilot signal in digital communication is a known value at both the transmitter and receiver, and is typically BPSK modulated. See any communications standard to see how the use pilots (LTE, DVB-T2, etc.)

 

[furqanaliali]

Thanking you all, but kindly tell me from where to study some MATHEMATICAL LITERATURE about pilot carriers in Digital Communication, because I did not find any in "Digital Communications 2e by Bernard Sklar" and "Digital Communications 4e by Proakis".

 

[Shug]

Thanking you all, but kindly tell me from where to study some MATHEMATICAL LITERATURE about pilot carriers in Digital Communication, because I did not find any in "Digital Communications 2e by Bernard Sklar" and "Digital Communications 4e by Proakis".

Why are you looking for mathematical literature on this topic? Standards specify the pilots, and they are used for estimation. I doubt there are many textbooks that include channel error estimation from pilots unless they are standards books.

If you want to find more information on channel estimation techniques and error analysis, you can do a search on channel estimation techniques/pilot pattern interpolators, or grab some books on LTE.

 

[Mityan]

Not sure what pilots are used for in analog communication, but they are regularly used in digital communication for the purposes of channel estimation, timing/frequency offset estimation, sampling clock offset estimation, etc. A pilot signal in digital communication is a known value at both the transmitter and receiver, and is typically BPSK modulated. See any communications standard to see how the use pilots (LTE, DVB-T2, etc.)

Analog communication example - relay commmands transmission over high voltage power lines. They use pilot tone to detect the channel is OK. Pilot fading together with any other discrete tone growth means command transmission. Without other tone - loss of channel. Tone and pilot together - false alarm (ignored).