# Equalization using channel estimates

**URL:** <https://www.ruby-forum.com/t/equalization-using-channel-estimates/238954>\
**Category:** GNU Radio\
**Created:** [February 5, 2014, 3:53pm UTC](https://www.ruby-forum.com/t/equalization-using-channel-estimates/238954 "2014-02-05T15:53:25Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [February 5, 2014, 3:53pm UTC](https://www.ruby-forum.com/t/equalization-using-channel-estimates/238954/1 "2014-02-05T15:53:25Z")

</div>

Dear All,

I’m trying to perform a simple way of equalization in OFDM transmission.  
I  
extracted the coefficients provided by the OFDM channel estimation  
block,  
and sent them back to the transmitter using a TCP socket.

Are these coefficients valid to use in equalization, i.e., can I divide  
the  
transmitted symbols by the corresponding channel coefficients, and  
therefore achieve an almost unity channel taps?

Thank you

–  
_---------------------------------------------------_  
_Mohammed Hassan Karmoose_  
_Teaching Assistant, Electrical Engineering Dept._  
_Faculty of Engineering, Alexandria University_  
_Al-Horeya Rd, El-Hadara,_ _Alexandria, Egypt - 21544_  
\*Tel: \*_++203-592-1852_ | \*Fax: \*_++203-592-1853_  
_Email: m [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid).h.karmoose@  
 [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)[ieee.org](http://ieee.org) [http://ieee.org](http://ieee.org)_  
_Website: [www.mkarmoose.com](http://www.mkarmoose.com) [http://www.mkarmoose.com/](http://www.mkarmoose.com/)_

---

<div class="post-metadata">

**Author:** ![Mohammed\_Karmoose](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/7c8e57/32.png) [@Mohammed\_Karmoose](https://www.ruby-forum.com/u/Mohammed_Karmoose)\
**Post date:** [February 5, 2014, 5:09pm UTC](https://www.ruby-forum.com/t/equalization-using-channel-estimates/238954/2 "2014-02-05T17:09:58Z")

</div>

On 05.02.2014 06:51, Mohammed Karmoose wrote:

> Dear All,
> 
> I’m trying to perform a simple way of equalization in OFDM transmission.  
> I extracted the coefficients provided by the OFDM channel estimation  
> block, and sent them back to the transmitter using a TCP socket.
> 
> Are these coefficients valid to use in equalization, i.e., can I divide  
> the transmitted symbols by the corresponding channel coefficients, and  
> therefore achieve an almost unity channel taps?

This is impossible to answer. It depends on so many things. When done  
right, you _can_ use channel coefficients to equalize, that’s the whole  
point of channel estimation and equalization.

You might find the examples in gr-digital/examples/ofdm/\*x\_ofdm.grc  
helpful.

MB

---

<div class="post-metadata">

**Author:** ![Mohammed\_Karmoose](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/7c8e57/32.png) [@Mohammed\_Karmoose](https://www.ruby-forum.com/u/Mohammed_Karmoose)\
**Post date:** [February 6, 2014, 9:31am UTC](https://www.ruby-forum.com/t/equalization-using-channel-estimates/238954/3 "2014-02-06T09:31:32Z")

</div>

-----BEGIN PGP SIGNED MESSAGE-----  
Hash: SHA1

Hi Mohammed,

I forgot to reply to the list in my previous mail, so I do this now.

On 05.02.2014 16:14, Mohammed Karmoose wrote:

> across a relatively long period of time, so it might seem that this  
> case should be magnified), the effective channel response somehow  
> is transformed back to the original (unaltered case) channel  
> response.  
> An example flowgraph would be very helpful in this case. Where exactly  
> do your samples get “transformed back”?

> what exactly do you want to achieve? Those channel estimates are
> 
> Hassan Karmoose\* \*/Teaching Assistant, Electrical Engineering  
> theft, I would have //executed the legal punishment on her//.‘’ -  
> Prophet Muhammad (PBUH)/  
> -----BEGIN PGP SIGNATURE-----  
> Version: GnuPG v1.4.12 (GNU/Linux)  
> Comment: Using GnuPG with Thunderbird - [http://www.enigmail.net/](http://www.enigmail.net/)

iQIcBAEBAgAGBQJS8liXAAoJEO7fmkDsqywMKKsQAJ6nhLqd6UazvRONAl8afe98  
uRmyZMJi7ktuaJ6DxMIY02AkLdXtAol60/cgdwmGQbsXuunDcP28HFOSN9JE216R  
7zjPjYb58CrzQdzAY1NExDq+RphvCX3GeCExSgvPhZR3TIz3pniEnqpNT/ik42cJ  
J1VGlu5nH2cRSov2qliPoFtX3jNeppOirAk51HUOKXe0ATQRTi+lcyFB4GMEuYJ2  
6Rq39eVoT30IaZRWVMxdqhwDP2qhMQIXKHx3b7E1lZnjN3fltXaQX7h5ijnCftdh  
FnimScpS4P6cXU/tSWRGk+brXLh26BVC+g+zG5BmrrZNuh+eNWtB0CAJjTaRlSre  
eUqQAbrpbzh2CkQr9o/Lvbfzu8V6sSAGy9fb25bVLCSckhDoFVCDiuaDD4rC5cJY  
BThqsUL9eMh6P2M+XRmTuerOk1u/kcuV7d4HD9nH+6XU3scdGCEgpL5qlcKc670W  
9vfbtO5P8KNRE3SnjnLxLC3ERH5FAAyPuHR1DQsSwmrJEB7aYD7Kgl3mCaoTG1b6  
gR3ae3D2Y5ppPmmeb42rEvlotJQqCF6CKgzZQo4WChsdEW7q6CbJxruRrBSI9lQi  
yLDlvzaHtv+OEUvN1i8GIVvPdf2ZR4Hye9jHtJXW+TBX4qDM1pOSzkat2SkDKXwK  
gAz40iS6WFC0ETg3Y8iq  
=DRvG  
-----END PGP SIGNATURE-----