From: Harald K. <kr...@ii...> - 2010-12-21 14:17:29
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Hello, i am currently evaluating the functionality of OpenBTS by looking at a BCCH carrier. Unfortunately I notice a break-in of the TX power in irregular intervals as shown in the figure in [1]. The length of the break-in's is around 2.154 ms or multiples of this value. I am using: OpenBTS 2.6.0Mamou built Sept. 19 2010 Kernel: 2.6.32.24-generic #ubuntu libusrp0 3.2.2.dfsg-1ubuntu USRP1 Rev. 4.5 FLEX900 daughter board Has someone also noticed such a behavior, or someone knows where it comes from, how to prevent it? regards, Harald [1] https://www.iis.ee.ethz.ch/~kroell/BCCH.png |
From: Alexander C. <ale...@gm...> - 2010-12-21 15:01:37
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Looks like you have underruns. Try running OpenBTS with real-time priority (with `chrt`) and tell us if it helps. On Tue, Dec 21, 2010 at 17:01, Harald Kröll <kr...@ii...> wrote: > Hello, > > i am currently evaluating the functionality of OpenBTS by looking at a > BCCH carrier. > > Unfortunately I notice a break-in of the TX power in irregular intervals > as shown in the figure in [1]. The length of the break-in's > is around 2.154 ms or multiples of this value. > > I am using: > > OpenBTS 2.6.0Mamou built Sept. 19 2010 > Kernel: 2.6.32.24-generic #ubuntu > libusrp0 3.2.2.dfsg-1ubuntu > USRP1 Rev. 4.5 > FLEX900 daughter board > > Has someone also noticed such a behavior, or someone knows where it > comes from, how to prevent it? > > regards, > > Harald > > [1] https://www.iis.ee.ethz.ch/~kroell/BCCH.png > > ------------------------------------------------------------------------------ > Lotusphere 2011 > Register now for Lotusphere 2011 and learn how > to connect the dots, take your collaborative environment > to the next level, and enter the era of Social Business. > http://p.sf.net/sfu/lotusphere-d2d > _______________________________________________ > Openbts-discuss mailing list > Ope...@li... > https://lists.sourceforge.net/lists/listinfo/openbts-discuss > -- Regards, Alexander Chemeris. http://www.fairwaves.ru |
From: Sylvain M. <24...@gm...> - 2010-12-21 19:09:53
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Hi, > Unfortunately I notice a break-in of the TX power in irregular intervals > as shown in the figure in [1]. The length of the break-in's > is around 2.154 ms or multiples of this value. > Has someone also noticed such a behavior, or someone knows where it > comes from, how to prevent it? Yes I've noticed the same. Do you get "dumping STALE bursts" message in the TRX logs ? (not those are the very beginning in the first 10 secs or so. Those are normal). I tried the real time priority but that didn't help much :( Cheers, Sylvain |
From: Alexander C. <ale...@gm...> - 2010-12-21 20:41:04
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Interesting. Are you sure it's not an underrun? On Tue, Dec 21, 2010 at 22:09, Sylvain Munaut <24...@gm...> wrote: > Hi, > >> Unfortunately I notice a break-in of the TX power in irregular intervals >> as shown in the figure in [1]. The length of the break-in's >> is around 2.154 ms or multiples of this value. > >> Has someone also noticed such a behavior, or someone knows where it >> comes from, how to prevent it? > > > Yes I've noticed the same. > > Do you get "dumping STALE bursts" message in the TRX logs ? (not > those are the very beginning in the first 10 secs or so. Those are > normal). > > I tried the real time priority but that didn't help much :( > > > Cheers, > > Sylvain > > ------------------------------------------------------------------------------ > Forrester recently released a report on the Return on Investment (ROI) of > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > within 7 months. Over 3 million businesses have gone Google with Google Apps: > an online email calendar, and document program that's accessible from your > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > _______________________________________________ > Openbts-discuss mailing list > Ope...@li... > https://lists.sourceforge.net/lists/listinfo/openbts-discuss > -- Regards, Alexander Chemeris. http://www.fairwaves.ru |
From: Harald K. <kr...@ii...> - 2010-12-23 07:58:33
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On 12/21/2010 08:09 PM, Sylvain Munaut wrote: > Hi, > >> Unfortunately I notice a break-in of the TX power in irregular intervals >> as shown in the figure in [1]. The length of the break-in's >> is around 2.154 ms or multiples of this value. > >> Has someone also noticed such a behavior, or someone knows where it >> comes from, how to prevent it? > > > Yes I've noticed the same. > > Do you get "dumping STALE bursts" message in the TRX logs ? (not > those are the very beginning in the first 10 secs or so. Those are > normal). > > I tried the real time priority but that didn't help much :( > > > Cheers, > > Sylvain Hi, changing the process priority reduces the probability of occurrence of a break-in slightly. In fact on our 2.4 GHz P4 machine OpenBTS uses 30 percent of the CPU power. By applying heavy CPU loads using the stress command, the signal breaks down immediately and ramps up after releasing the stressing. During the break-in lines like the following are written in the TRX log: 1293089329.9532 NOTICE 3077458800 Transceiver.cpp:146:pushRadioVector: dumping STALE burst in TRX->USRP interface It seems like mTransmitPriorityQueue is not updated in time. Any suggestions to handle this? Cheers, Harald |