Re: [Discuss-gnuradio] Spread Specturm implementation in FPGA

[Firas A.]

Hi, 


> Yong J. Chang" wrote:
> Hi All,
>
> I've worked on Embedded system and FPGA systems for several years and I
> joined the team working on GNU Radio > project. Because of my lack of
> knowledge about digital communication, I need some help of you all.
>
> The goal is simple PAM modulated communication with M-sequence spreading.
> So far as I know, this can be done in 
> host PC level. However, our goal is that this is implemented in FPGA level
> in real-time because we have to determine > exact time of packet arriving. 
>
> The question is following.
>
> If I implement the despreader ( is it called synchronizer? including
> detecting and tracking ) in FPGA, should I perform 
> symbol timing recovery in host PC again? If we use the despreader and can
> detect the peak of correlation between 
> received signal and spreading code, I don't think that I have to recover
> symbol timing again because the despreaded 
> signal is already symbol-spaced signal captured at nice time. But I'm not
> sure that I'm right or wrong.
>
> And I hope that this can be done in Cyclone FPGA!!!!
>
> Thank you all!
>
> Y. J. Chang


I'm not sure how it is possible to do the spreading with PAM, but I think
doing spreading with PWM is much easier. Also to conserve space in USRP
FPGA, you have to use the image with 1 RX and 1 TX. This will free about 55%
of FPGA resources.

Best Regards,

Firas
-- 
View this message in context: 
http://www.nabble.com/Spread-Specturm-implementation-in-FPGA-tp21380279p21396189.html
Sent from the GnuRadio mailing list archive at Nabble.com.