REG: AutoRgressive Model

Hi all,
I'm trying to model my channel using auto regressive model. I have a doubt in that model. After finding the AR parameters using the yule walker equation, please tell me on how to find the poles from this parameters?. Can you also please suggest me some procedure on how to properly model the channel frequency response using AR(P) model?. I want to compare my measured PDP with this model. Please give some suggestions.

Thanks in advance,

Regards,
David.