[USRP-users] Gen2 reader

mahran nedal mahran2010sawya at hotmail.com
Sat Dec 6 12:51:08 EST 2014


hello Marcus,
How do you plot the signal?>> I used octave to plot my signal. I plot the output for the received signal after the match filter to see what happen .I don't know either. When you record the samples you send to the USRP for transmission to a file simultaneously, and analyze them, do they show the same drop out?
>   I save my results for what happen between reader and tag into log file if you mean that ? . Yes when i open the log file i see the same results just one query through the cycle and after that my reader start a new cycle which mean the carrier dropped.
> > I change the time that when the carrier should power down 
> >to check what happen but with no change on the received signal. 
> 
> Why do you power down the carrier?

> Sorry this is  my mistake i change the period when the reader power down not carrier wave .
I change :  int min_cw = 1500;tail_cw = 250; 
to see what happen but the same result and i change :


    > As far as I could understand the running diagrams you referred to, there was no period where the carrier has to be powered down.
>   I guess there is period as i mentioned in the previous question , you can go through buttner code (Reader _f.cc) to see this value.
> > I
> >modified the code for buttner that work on usrp 1.the code very large
> >and complicated to mention it. If you know please any one maybe work on
> >this topic .
> 
> I'd assume no one else is working on the same standard, but there were projects concerned with reading rfid tags using USRPs before.
> 

Eng.Mahran jazi
 
Teaching assistant
 
AL-Quds university
 
Mobile:0599944458


> Subject: RE: [USRP-users] Gen2 reader
> From: marcus.mueller at ettus.com
> Date: Sat, 6 Dec 2014 00:08:48 +0100
> To: mahran2010sawya at hotmail.com; usrp-users at lists.ettus.com
> 
> Hello Mahran,
> 
> I really don't make much progress understanding you, I'm afraid :( 
> Could you please directly answer the questions I inserted into your email below?
> 
> 
> On December 5, 2014 7:37:52 PM CET, mahran nedal <mahran2010sawya at hotmail.com> wrote:
> >Hello Marcus,
> >Thank you for your reply and attention . I let my reader to send the
> >carrier wave continuously, But when i plot the received signal i see
> How do you plot the signal?
> >that the carrier wave after each cycle dropped ,Really i dont know why
> >is that ? 
> 
> I don't know either. When you record the samples you send to the USRP for transmission to a file simultaneously, and analyze them, do they show the same drop out?
>  
> > I change the time that when the carrier should power down 
> >to check what happen but with no change on the received signal. 
> 
> Why do you power down the carrier?
> 
> As far as I could understand the running diagrams you referred to, there was no period where the carrier has to be powered down.
> 
> > I
> >modified the code for buttner that work on usrp 1.the code very large
> >and complicated to mention it. If you know please any one maybe work on
> >this topic .
> 
> I'd assume no one else is working on the same standard, but there were projects concerned with reading rfid tags using USRPs before.
> 
> Best regards,
> Marcus Müller 
> 
> >
> >Thanks,
> >
> >
> >
> >> Date: Fri, 5 Dec 2014 11:49:15 +0100
> >> From: marcus.mueller at ettus.com
> >> To: mahran2010sawya at hotmail.com; usrp-users at lists.ettus.com
> >> Subject: Re: [USRP-users] Gen2 reader
> >> 
> >> 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
> >		 	   		  
> >> 
> > 		 	   		  
> 
> -- 
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
 		 	   		  
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