Re: [Discuss-gnuradio] How to implement a TDMA system
On 04/23/2012 08:14 AM, Nowlan, Sean wrote: > In my case, I modified the stream tag example under gr-uhd/examples > to make a "burst_tagger" block. I kept the work function essentially > the same since it already handles bursting for a specified duration > and repeats this behavior over a specified cycle time. This method of > bursting works nicely. The stream tags you need to care about are > called "tx_time", "tx_sob" (start-of-burst), and "tx_eob" > (end-of-burst), respectively. These tags are affixed in the work > function of the stream tags example mentioned above. The > gr_uhd_usrp_sink block already has the logic to translate these tags > into UHD commands, so you shouldn't need to worry about that. > > I don't think you can do this from Python yet, but I could be wrong > about that. > Not yet, but here are the docs for it: http://gnuradio.org/redmine/projects/gnuradio/wiki/BlocksCodingGuide#Stream-Tags This branch has the python support: https://github.com/guruofquality/gnuradio/tree/python_blocks2 -josh ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] How to implement a TDMA system
In my case, I modified the stream tag example under gr-uhd/examples to make a "burst_tagger" block. I kept the work function essentially the same since it already handles bursting for a specified duration and repeats this behavior over a specified cycle time. This method of bursting works nicely. The stream tags you need to care about are called "tx_time", "tx_sob" (start-of-burst), and "tx_eob" (end-of-burst), respectively. These tags are affixed in the work function of the stream tags example mentioned above. The gr_uhd_usrp_sink block already has the logic to translate these tags into UHD commands, so you shouldn't need to worry about that. I don't think you can do this from Python yet, but I could be wrong about that. One last thing I'll mention is that there is a "set_start_time" function in gr_uhd_usrp_sink that can set an absolute start time for transmission (essentially the USRP will block the stream from the flowgraph until the USRP's internal time register reaches the time you set). Sean From: discuss-gnuradio-bounces+sean.nowlan=gtri.gatech@gnu.org [discuss-gnuradio-bounces+sean.nowlan=gtri.gatech@gnu.org] on behalf of Pan, Luyuan [panluy...@gmail.com] Sent: Monday, April 23, 2012 11:04 AM To: Tom Rondeau Cc: discuss-gnuradio@gnu.org Subject: Re: [Discuss-gnuradio] How to implement a TDMA system Hello, Thank you so much for your reply. And I also read your presentation and audio about "Stream tag" on the website of GnuRadio Conference 2011, I want to know a few questions about it: 1. I think you defined some auxiliary control information to make the stream start or stop on desired time, but above the UHD/gr-uhd and has nothing to do with UHD, did I misunderstand it? 2. May I use the "stream tag" to achieve my goal of TDMA system?(consider the precision and efficiency) 3. If so, and as the time-stamp cannot get through the gr-uhd, whether is it more convenient for me to use the "stream tag"? Or maybe I can code in some higher level like python? Any comment/suggestion is greatly appreciated, thank you~ -- Best regards, Luyuan Pan [cid:part1.04070301.02080702@gmail.com] Tom Rondeau<mailto:t...@trondeau.com> 2012年4月23日 22:15 On Sun, Apr 22, 2012 at 3:16 AM, Pan, Luyuan <mailto:panluy...@gmail.com> wrote: Hi everyone, I want to implement a TDD system with three USRP2 and an IBM server with three Ethernet cards. The scenario is one relay and two nodes exchange data through the relay, I want them to transmit data in their fixed time slot, it does not need to be too precise, about 100 milliseconds per slot is OK. The question is: 1. Can I achieve my goal with the current equipment? I'm pretty sure, yes. The 100 ms should be pretty easily achievable. 2. I want to use the time-stamp in UHD to precise control the time to send and recv, but without external clock, does the UHD have to use the external clock to get the time? No, you do not need an external clock for this. All time in the UHD land is relative, so you should be able to say "send packet 100 ms from now" without caring what absolute time 'now' is. Tom Thank you in advance! -- Best regards, Pan, Luyuan [cid:part1.04070301.02080702@gmail.com] Pan, Luyuan<mailto:panluy...@gmail.com> 2012年4月22日 15:16 Hi everyone, I want to implement a TDD system with three USRP2 and an IBM server with three Ethernet cards. The scenario is one relay and two nodes exchange data through the relay, I want them to transmit data in their fixed time slot, it does not need to be too precise, about 100 milliseconds per slot is OK. The question is: 1. Can I achieve my goal with the current equipment? 2. I want to use the time-stamp in UHD to precise control the time to send and recv, but without external clock, does the UHD have to use the external clock to get the time? Thank you in advance! <>___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] How to implement a TDMA system
Hello, Thank you so much for your reply. And I also read your presentation and audio about "Stream tag" on the website of GnuRadio Conference 2011, I want to know a few questions about it: 1. I think you defined some auxiliary control information to make the stream start or stop on desired time, but above the UHD/gr-uhd and has nothing to do with UHD, did I misunderstand it? 2. May I use the "stream tag" to achieve my goal of TDMA system?(consider the precision and efficiency) 3. If so, and as the time-stamp cannot get through the gr-uhd, whether is it more convenient for me to use the "stream tag"? Or maybe I can code in some higher level like python? Any comment/suggestion is greatly appreciated, thank you~ -- Best regards, Luyuan Pan Tom Rondeau 2012年4月23日 22:15 On Sun, Apr 22, 2012 at 3:16 AM, Pan, Luyuan wrote: Hi everyone, I want to implement a TDD system with three USRP2 and an IBM server with three Ethernet cards. The scenario is one relay and two nodes exchange data through the relay, I want them to transmit data in their fixed time slot, it does not need to be too precise, about 100 milliseconds per slot is OK. The question is: 1. Can I achieve my goal with the current equipment? I'm pretty sure, yes. The 100 ms should be pretty easily achievable. 2. I want to use the time-stamp in UHD to precise control the time to send and recv, but without external clock, does the UHD have to use the external clock to get the time? No, you do not need an external clock for this. All time in the UHD land is relative, so you should be able to say "send packet 100 ms from now" without caring what absolute time 'now' is. Tom Thank you in advance! -- Best regards, Pan, Luyuan Pan, Luyuan 2012年4月22日 15:16 Hi everyone, I want to implement a TDD system with three USRP2 and an IBM server with three Ethernet cards. The scenario is one relay and two nodes exchange data through the relay, I want them to transmit data in their fixed time slot, it does not need to be too precise, about 100 milliseconds per slot is OK. The question is: 1. Can I achieve my goal with the current equipment? 2. I want to use the time-stamp in UHD to precise control the time to send and recv, but without external clock, does the UHD have to use the external clock to get the time? Thank you in advance! ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] How to implement a TDMA system
On Sun, Apr 22, 2012 at 3:16 AM, Pan, Luyuan wrote: > Hi everyone, > I want to implement a TDD system with three USRP2 and an IBM server with > three Ethernet cards. The scenario is one relay and two nodes exchange data > through the relay, I want them to transmit data in their fixed time slot, it > does not need to be too precise, about 100 milliseconds per slot is OK. The > question is: > 1. Can I achieve my goal with the current equipment? I'm pretty sure, yes. The 100 ms should be pretty easily achievable. > 2. I want to use the time-stamp in UHD to precise control the time to send > and recv, but without external clock, does the UHD have to use the external > clock to get the time? No, you do not need an external clock for this. All time in the UHD land is relative, so you should be able to say "send packet 100 ms from now" without caring what absolute time 'now' is. Tom > Thank you in advance! > -- > Best regards, > Pan, Luyuan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] How to implement a TDMA system
Hi everyone, I want to implement a TDD system with three USRP2 and an IBM server with three Ethernet cards. The scenario is one relay and two nodes exchange data through the relay, I want them to transmit data in their fixed time slot, it does not need to be too precise, about 100 milliseconds per slot is OK. The question is: 1. Can I achieve my goal with the current equipment? 2. I want to use the time-stamp in UHD to precise control the time to send and recv, but without external clock, does the UHD have to use the external clock to get the time? Thank you in advance! -- Best regards, Pan, Luyuan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
