Phase noise how to combine together with the transmitting signals

Dear all:

Now i am working on a simulation to model Phase Noise and evaluate the
distortion. 

In many web tutorials, the definition of phase noise is given. 

But who can help tell how to generate certain phase noise from AWGN and
combine the phase noise with the transmitting signal? e.g. 16QAM.

Many thanks. 

On Dec 27, 8:10 am, "raymondpsl" <raymond...@yahoo.com.sg> wrote:
> Dear all:
>
> Now i am working on a simulation to model Phase Noise and evaluate the
> distortion.
>
> In many web tutorials, the definition of phase noise is given.
>
> But who can help tell how to generate certain phase noise from AWGN and
> combine the phase noise with the transmitting signal? e.g. 16QAM.
>
> Many thanks.

I don't know what the official method is, but what I have done is
build a FIR filter to match the double sided phase noise spectrum,
pass white noise through it, then phase modulate the constellation
with the filtered noise. Your constellation points should turn into
arcs.

John

On Dec 27, 6:10 pm, "raymondpsl" <raymond...@yahoo.com.sg> wrote:
> But who can help tell how to generate certain phase noise from AWGN and
> combine the phase noise with the transmitting signal? e.g. 16QAM.


Long back (2000 around), in 802.11 task group-b, Intersil engineers
have proposed a
phase noise model based on filtering white gaussian noise with a first
order butterworth
low pass filter.

The ppt describing the modeling and the Matlab code can be found here
Suggested Phase Noise Model for 802-11 HRb - Mark Webster, Mike Seals,
Intersil, September 2000
http://grouper.ieee.org/groups/802/11/Documents/DocumentHolder/0-296.zip

HTH,
Krishna
http://www.dsplog.com

>On Dec 27, 8:10 am, "raymondpsl" <raymond...@yahoo.com.sg> wrote:
>> Dear all:
>>
>> Now i am working on a simulation to model Phase Noise and evaluate the
>> distortion.
>>
>> In many web tutorials, the definition of phase noise is given.
>>
>> But who can help tell how to generate certain phase noise from AWGN
and
>> combine the phase noise with the transmitting signal? e.g. 16QAM.
>>
>> Many thanks.
>
>I don't know what the official method is, but what I have done is
>build a FIR filter to match the double sided phase noise spectrum,
>pass white noise through it, then phase modulate the constellation
>with the filtered noise. Your constellation points should turn into
>arcs.
>
>John
>

Thanks a lot for your reply..
I will try your method. :-)

Yes, depending on what you want to achieve with your model, a one-pole LP
may do, or it may need to be more sophisticated.

Generally:
- generate a real-valued signal "pn" that has the desired phase noise
spectrum (for example by filtering AWGN)
- phase-modulate your Tx signal, meaning multiply with exp(i pn)

It's probably already more accurate than needed, unless you're
investigating some specialist topic. 
If you need to be more accurate, there are lots of details. For example,
some phase noise processes may appear separately on in-phase and
quadrature branch (uncorrelated), others are shared (correlated).