[USRP-users] Gen2 reader

Marcus Müller marcus.mueller at ettus.com
Fri Dec 5 05:49:15 EST 2014


Hello Mahran,

I must admit that I had trouble understanding the complex problem you're
describing.

I'll go ahead and try to insert my questions into your mail, so that I
can get to a full understanding.
On 12/04/2014 06:40 PM, mahran nedal wrote:
> yes between transmissions the carrier wave dropped or in every cycle .
I assume that is correct by design?
> My implementation based on EPC Class-1 Generation-2 protocol please see http://www.gs1.org/gsmp/kc/epcglobal/uhfc1g2  V2.2 (page 26,42).
I assume you're referring to the v2.0 document -- there's only a
two-page v2.2 "fact sheet".
I must admit that I can't really justify reading a complex standards
document on worktime -- however, the timing diagram on page 42 indicates
that the interrogator must continously send, so that is what your
application must ensure.
> The reader or interrogator send the signal which contains a Query ,all the  communication parameters  includes inside the query  like preamble ,etc. the signal encoding by pulse interval encoding and modulated by ASK ,the tag receive the signal and back-scattering again to the reader ,through this time the carrier wave energize the tag for response .
Yes, I understand.
> I success to read one tag per cycle ,but until now i cant let the carrier wave continuous all the time .
Why?
>  What is happening that when the reader send a query to the tag , the tag response its RN16 ,the reader Acknowledged it ,and the tag send the ID after that the carrier wave dropped 
why do you let the carrier wave drop? The timing diagram says "continous
wave", so from what I understand you must ensure that your interrogator
is always either sending data or a naked carrier.

>From what I understand, you are implementing the interrogator, is that
correct?

> and start again with each transmission and this is a problem because  when i ran the anti- collision protocol which mean that i should send the number of slots through the query for many tags and every tag choose one slot and response back to the reader ,so i should see through the query for example 3 tag response before the new cycle start but i cant i see just one ,because the carrier wave dropped every cycle.
Sorry, this I did not understand.
> Hope to hear from you as soon as Thanks,
> Eng.Mahran jazi
Greetings,
Marcus

>
>
> Date: Wed, 3 Dec 2014 19:03:12 +0100
> To: usrp-users at lists.ettus.com
> Subject: Re: [USRP-users] Gen2 reader
> From: usrp-users at lists.ettus.com
>
>
>   
>     
>   
>   
>     Hello Mahran
>
>     
>
>     this is an interesting application.
>
>     
>
>     I'd like to understand what's going wrong here:
>
>     You say the USRP doesn't continously send a carrier wave. I assume
>     this is happening between your transmissions?
>
>     
>
>     The USRP will send any signal you want and will try to be as silent
>     as possible as long as you are not transmitting. If you want a
>     continous carrier, you will have to continously send samples
>     containing the appropriate signal. 
>
>     Since the N210 architecture is by principle full-duplex capable, as
>     are the RFX daughterboards, this should normally not be a problem,
>     unless crosstalk is problematic (e.g. it saturates your RX
>     amplifiers/mixers).
>
>     
>
>     Could you please explain in more detail how you transit your signals
>     (including the carrier)?
>
>     
>
>     Best regards,
>
>     Marcus
>
>     
>
>     On 12/03/2014 06:51 PM, mahran nedal
>       via USRP-users wrote:
>
>     
>     
>       Hi,
>
> Im working to implement gen 2 reader based on new generation of usrp n210 with RFX900 daughter board  to read the commercial tags. I success to read commercial tag . now i investigate to read many tags based on dynamic framed slotted aloaha , the main problem that the usrp cant continuously send the carrier wave through one cycle ,the carrier wave dropped and start again with each cycle so i cant sent many slots in each cycle because this problem . i debugging the software no problem . Is there any limitation on this hardware or daughter borad that cant support full-duplex 
>  
> Really i need help .
>
>
> Thanks,
> Eng. jazi
>  
>
>  		 	   		  
>
>       
>
>       
>       
>
>       _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>     
>     
>
>   
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com 		 	   		  





More information about the USRP-users mailing list