# Limesdr gr-osmocom latency

**URL:** <https://discourse.myriadrf.org/t/limesdr-gr-osmocom-latency/1741>\
**Category:** LimeSDR\
**Created:** [26 September 2017 11:06 UTC](https://discourse.myriadrf.org/t/limesdr-gr-osmocom-latency/1741 "2017-09-26T11:06:05Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![ashtum](https://avatars.discourse-cdn.com/v4/letter/a/85f322/32.png) [@ashtum](https://discourse.myriadrf.org/u/ashtum)\
**Post date:** [26 September 2017 11:06 UTC](https://discourse.myriadrf.org/t/limesdr-gr-osmocom-latency/1741/1 "2017-09-26T11:06:05Z")

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Hi ,  
I build one two way modem with two limesdr boards in gnuradio , Sample rate for rx and tx is 3 Msample but the problem is , i get 3700ms round trip delay between two board !  
I reduced blocks output buffer but it doesn’t make difference on latency (just reduce 100ms) .  
I think the problem is gr-osmocom block and limesdr buffers between host driver and fpga.  
How i can reduce this buffers to reduce total latency ?

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**Author:** ![samv](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@samv](https://discourse.myriadrf.org/u/samv)\
**Post date:** [13 April 2018 15:35 UTC](https://discourse.myriadrf.org/t/limesdr-gr-osmocom-latency/1741/2 "2018-04-13T15:35:13Z")

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hello,  
I have the same problem!

i tried first to send with a 600ksamples and I have 16seconds delay… 😱  
Then I sent with a same samples as you (3Msamples) and got the same result… 4seconds! better than before but not acceptable for a real time com 😖

How did you solved this problem?( if you solved it?) Is there any possibility that a buffer is too big?

Thanks

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**Author:** ![ashtum](https://avatars.discourse-cdn.com/v4/letter/a/85f322/32.png) [@ashtum](https://discourse.myriadrf.org/u/ashtum)\
**Post date:** [13 April 2018 15:41 UTC](https://discourse.myriadrf.org/t/limesdr-gr-osmocom-latency/1741/3 "2018-04-13T15:41:39Z")

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Hi,  
I didn’t have time for more investigation , but this topic may help you: [Minimising round-trip latency](https://discourse.myriadrf.org/t/minimising-round-trip-latency/2125)

Cheers.

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**Author:** ![samv](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@samv](https://discourse.myriadrf.org/u/samv)\
**Post date:** [16 April 2018 05:28 UTC](https://discourse.myriadrf.org/t/limesdr-gr-osmocom-latency/1741/4 "2018-04-16T05:28:02Z")

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Thank you for your answer, i will try le soapyUHD block and all the tips written in this thread.

Cheers