https://osmocom.org/https://osmocom.org/favicon.ico?16647414092018-06-14T07:02:49ZOpen Source Mobile CommunicationsOsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=99072018-06-14T07:02:49Zlaforge
<ul><li><strong>Related to</strong> <i><a class="issue tracker-2 status-3 priority-3 priority-high3 closed" href="/issues/2919">Feature #2919</a>: Native LimeSDR support</i> added</li></ul> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=114112018-09-18T06:54:16Zduo_kali
<ul></ul><p>Tested also with 900MHZ, seems the output power and rx gain using osmo-trx-lms is less compare using osmo-trx-uhd.</p>
<p>I dont have the spectum analyzer here, but testing many times and compare using phone to camp and call with osmo-trx-uhd has produce more power than osmo-trx-lms, so automatically using UHD increase range coverage.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=125542018-11-11T17:13:53ZArmin
<ul></ul><p>Have the same issue with LimeSDR mini connected via USB3 to my host machine. LimeSDR mini producing only -12dBm RF power tuned and transmitting my GSM network on 935.0 MHz.<br />When I used LimeSuite to transmit CW on max possible power setting, I got 13.2 dBm on 935 MHz. <br />I tried also to play with some config parameters of osmo-bts, like</p>
<p><em>user-gain Inform BTS about additional, user-provided gain or attenuation at TRX output<br />power-ramp Power-Ramp settingsMaximum initial power</em></p>
<p>but these parameters doesn't change anything.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=126012018-11-17T21:19:45ZArmin
<ul></ul><p>I was able to increase output power by using in osmo-trx-limesdr.cfg in trx section</p>
<p><em>tx-path BAND2</em></p>
<p>instead of BAND1</p>
<p>This increased power to 5 dBm.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=127002018-11-26T15:17:24Zlaforge
<ul><li><strong>Status</strong> changed from <i>New</i> to <i>In Progress</i></li><li><strong>Assignee</strong> set to <i>pespin</i></li><li><strong>% Done</strong> changed from <i>0</i> to <i>50</i></li></ul><p>the output level is expected to be rather low (-5 dBm?). Lower levels were likely a result of using only 30% of the full 16bit sample scale (see <a class="issue tracker-1 status-7 priority-3 priority-high3" title="Bug: osmo-trx-lms RF Envelope FAIL on LimeSDR, but not on LimeSDR-mini (Stalled)" href="https://osmocom.org/issues/3341">#3341</a>).</p>
<p>One remaining difficulty is to know which port (BAND1/BAND2) is ideal for a given transimt frequency. It seems that the LimeSDR-mini vs. LimeSDR-USB have inverted recommendations about which ports shall be used for which frequency. We've asked lime to provide a related table, so we can then in software at least print a warning if a user selects a sub-optimal combination.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=127892018-11-29T12:30:58Zlaforge
<ul><li><strong>Assignee</strong> changed from <i>pespin</i> to <i>roh</i></li></ul><p>See <a class="external" href="https://gerrit.osmocom.org/#/c/osmo-trx/+/12006/">https://gerrit.osmocom.org/#/c/osmo-trx/+/12006/</a> <a class="external" href="https://gerrit.osmocom.org/#/c/osmo-trx/+/12007/">https://gerrit.osmocom.org/#/c/osmo-trx/+/12007/</a> <a class="external" href="https://gerrit.osmocom.org/#/c/osmo-trx/+/12008/">https://gerrit.osmocom.org/#/c/osmo-trx/+/12008/</a></p>
<p><a class="user active" href="https://osmocom.org/users/72">roh</a> please re-test using those changes, and <strong>without</strong> using any 'osmotrx tx-attenuation' in your config files</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=131452019-01-25T20:13:25Zroh
<ul><li><strong>File</strong> <a href="/attachments/3526">limesdr_mini_1_phase_lms1810git_extclock40.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3526/limesdr_mini_1_phase_lms1810git_extclock40.gif">limesdr_mini_1_phase_lms1810git_extclock40.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3527">limesdr_mini_1_env_lms1810git_extclock40.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3527/limesdr_mini_1_env_lms1810git_extclock40.gif">limesdr_mini_1_env_lms1810git_extclock40.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3528">limesdr_mini_871_env_lms1810git_extclock40.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3528/limesdr_mini_871_env_lms1810git_extclock40.gif">limesdr_mini_871_env_lms1810git_extclock40.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3529">limesdr_mini_871_phase_lms1810git_extclock40.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3529/limesdr_mini_871_phase_lms1810git_extclock40.gif">limesdr_mini_871_phase_lms1810git_extclock40.gif</a> added</li></ul><p>i generated these (very good looking) pictures by using a limesdr mini V1.2 modded for external clock and feeding a 40MHz sinewave with 5.2dBm as reference, locked to the 10MHz generator of the 4406.</p>
<p>thus all frequency or phase errors should be rooted in the lime domain.<br />the only patch used so far was to make osmo-trx-lms use 40 instead of 10MHz.<br />usb connection to testsystem (apu2) is usb2 (better stability)</p>
<p>osmo-bts-trx.cfg<br /><pre>
phy 0
instance 0
osmotrx ip local 127.0.0.1
osmotrx ip remote 127.0.0.1
bts 0
band 900
ipa unit-id 1801 0
oml remote-ip 127.0.0.1
gsmtap-sapi ccch
gsmtap-sapi pdtch
trx 0
phy 0 instance 0
</pre></p>
<p>osmo-trx-lms.cfg:<br /><pre>
trx
bind-ip 127.0.0.1
remote-ip 127.0.0.1
base-port 5700
egprs disable
tx-sps 4
rx-sps 4
clock-ref external
rt-prio 18
chan 0
tx-path BAND1
rx-path LNAW
</pre></p>
<p>output of osmo-trx-lms: (only once, since the output is the same for 900/1800)<br /><pre>
...
Fri Jan 25 20:30:36 2019 DLMS <0003> LMSDevice.cpp:102 [tid=140567255682880] Selected TX path: Band 2
Fri Jan 25 20:30:36 2019 DLMS <0003> LMSDevice.cpp:102 [tid=140567255682880] Selected RX path: LNAW
...
Fri Jan 25 20:30:40 2019 DDEV <0002> LMSDevice.cpp:386 [tid=140567255922432] chan 0: Setting TX gain to 36.5 dB
Fri Jan 25 20:30:40 2019 DDEV <0002> LMSDevice.cpp:401 [tid=140567255922432] chan 0: Setting RX gain to 36.5 dB
...
Fri Jan 25 20:30:41 2019 DDEV <0002> LMSDevice.cpp:386 [tid=140567255922432] chan 0: Setting TX gain to 73 dB
...
</pre></p>
<p>note: band2 is selected even if the config says band1 (setting is ignored)</p>
<a name="results"></a>
<h2 >results:<a href="#results" class="wiki-anchor">¶</a></h2>
<p>current default settings from head generate about 11.5dBm output power on gsm900 and -3.5dBm on gsm1800<br />gsm1800 with those settings generates in a lot phase noise, which FAILs those measurements.</p>
<p>todo:<br />test with a limited output power, to get the 1800MHz band to work properly (apply <a class="external" href="https://gerrit.osmocom.org/#/c/osmo-trx/+/12008/">https://gerrit.osmocom.org/#/c/osmo-trx/+/12008/</a>) (12006/12007 are merged already)</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=131642019-01-28T14:48:50Zroh
<ul></ul><p><a class="external" href="https://gerrit.osmocom.org/#/c/osmo-trx/+/12008/">https://gerrit.osmocom.org/#/c/osmo-trx/+/12008/</a> does not help this further, since it only changes the default value set initially from 36.5 dB to 64.0 dB which is overwritten a few seconds later by a setTxGain call for maximum (which is still hardcoded in LMSDevice::maxTxGain).</p>
<p>the same result can be reached by using this osmo-bts-trx.cfg<br /><pre>
phy 0
instance 0
osmotrx tx-attenuation 9
</pre></p>
<p>anyhow.. reducing the tx-gain does only make the rf envelope worse to the level that it hardly keeps passing. is this really a hardware gain, and not some sw-scaling?</p>
<p>phase noise is not changing visibly.</p>
<p>since it seems that limesdr mini and limesdr have different default gains? (not completely sure, just assuming) we would need some kind of hw-detection in this code if we want to config them differently.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=131662019-01-28T15:48:24Zroh
<ul><li><strong>File</strong> <a href="/attachments/3535">limesdr_usb_871_env_lms1810git_extclock10.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3535/limesdr_usb_871_env_lms1810git_extclock10.gif">limesdr_usb_871_env_lms1810git_extclock10.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3536">limesdr_usb_871_env_lms1810git_extclock10_tx-att_9.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3536/limesdr_usb_871_env_lms1810git_extclock10_tx-att_9.gif">limesdr_usb_871_env_lms1810git_extclock10_tx-att_9.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3537">limesdr_usb_871_env_lms1810git_extclock40.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3537/limesdr_usb_871_env_lms1810git_extclock40.gif">limesdr_usb_871_env_lms1810git_extclock40.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3538">limesdr_usb_871_env_lms1810git_extclock40_tx-att_9.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3538/limesdr_usb_871_env_lms1810git_extclock40_tx-att_9.gif">limesdr_usb_871_env_lms1810git_extclock40_tx-att_9.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3539">limesdr_usb_871_phase_lms1810git_extclock10.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3539/limesdr_usb_871_phase_lms1810git_extclock10.gif">limesdr_usb_871_phase_lms1810git_extclock10.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3540">limesdr_usb_871_phase_lms1810git_extclock10_tx-att_9.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3540/limesdr_usb_871_phase_lms1810git_extclock10_tx-att_9.gif">limesdr_usb_871_phase_lms1810git_extclock10_tx-att_9.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3541">limesdr_usb_871_phase_lms1810git_extclock40.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3541/limesdr_usb_871_phase_lms1810git_extclock40.gif">limesdr_usb_871_phase_lms1810git_extclock40.gif</a> added</li><li><strong>File</strong> <a href="/attachments/3542">limesdr_usb_871_phase_lms1810git_extclock40_tx-att_9.gif</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/3542/limesdr_usb_871_phase_lms1810git_extclock40_tx-att_9.gif">limesdr_usb_871_phase_lms1810git_extclock40_tx-att_9.gif</a> added</li></ul><p>i have replicated some of these tests on a limesdr usb now. it seems it makes a minor difference if the device is fed with 10MHz or 40MHz from the same clockgenerator (E4433b external clocked by a E4406 via 10MHz bnc cable from reference out to reference in)</p>
<p>i get a bit worse results with 40MHz clock than with 10MHz, but since its the same generator and i can see no harmonics or similar distortion, so i am unsure where this phase noise is coming from.. PASS is not 'solid' but flappy.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=131822019-01-29T17:30:45Zroh
<ul></ul><p>it seems the clockchip used on lime mini (ti LMK00105) is not happy with sinewaves and wants sharp rectangles 2V/ns or better.</p>
<p>this means i need to redo all these measurements as soon as i have a clockgenerator with proper rectangle output</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=133592019-02-14T16:33:45Zroh
<ul><li><strong>Blocked by</strong> <i><a class="issue tracker-1 status-7 priority-2 priority-default" href="/issues/3775">Bug #3775</a>: properly debug limesdr usb and limesdr mini clocking requirements and osmo-trx support</i> added</li></ul> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=150152019-06-27T17:29:50Zroh
<ul></ul><p>after limiting the tx-level in osmo-trx-lms for the different plattforms we have these real-world signal power levels:</p>
<p>all measurements done on 2019-06-27 with limesuite 19.04 from osmocom-nightly</p>
limesdr usb: (measured with external 10MHz rectangle clock)
<ul>
<li>arfcn 5 = ~+11dBm</li>
<li>arfcn 871 = ~+3dBm - phase error high - reduce tx power by 8dB to ~-5dBm - phase error OK</li>
</ul>
limesdr mini (measured with internal clock)
<ul>
<li>arfcn 5 = ~+3dBm</li>
<li>arfcn 871 = ~-12dBm</li>
</ul>
limenet micro (gps clock)
<ul>
<li>arfcn 5 = ~+7dBm</li>
<li>arfcn 871 = ~-5dBm - phase error high - reduce tx power does <em>NOT</em> help reduce phasenoise for whatever reason. (not even 30dB)</li>
</ul> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=150162019-06-27T17:35:29Zroh
<ul><li><strong>% Done</strong> changed from <i>50</i> to <i>90</i></li></ul><p>we currently do not have a frequency-dependent but only device-dependent max-tx-power settings:</p>
<p>LimeSDR-USB -> 73<br />LimeSDR-Mini -> 66<br />LimeNET-Micro etc -> 71</p>
<p>if we really want osmo-trx to not do 'stupid waveforms' i could add a patch reducing power e.g. for LimeSDR-usb on DCS1800, but i would rather like to avoid this.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=150232019-06-28T02:30:44Zlaforge
<ul></ul><p>On Thu, Jun 27, 2019 at 05:29:50PM +0000, roh [REDMINE] wrote:</p>
<blockquote>
limenet micro
<ul>
<li>arfcn 5 = ~+7dBm</li>
<li>arfcn 871 = ~-5dBm - phase error high - reduce tx power does <em>NOT</em> help reduce phasenoise for whatever reason. (not even 30dB)</li>
</ul>
</blockquote>
<p>the comparatively poor phase error onthe limenet micro is distrurbing. Please make sure to reach<br />out to Lime Micro about this. It would be sad if the board intended for actual base station<br />operation would be the only that doesn't provide 3GPP-spec-compliant waveforms :/</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=161362019-10-01T16:04:04Zroh
<ul></ul><p>please see also <a class="external" href="https://osmocom.org/projects/osmotrx/wiki/LimeSDR_Family">https://osmocom.org/projects/osmotrx/wiki/LimeSDR_Family</a> for an overview of recommended settings and to be expected power levels.</p>
<p>i am checking with lime if anything can be done about the limenet micro levels and the dcs1800 issues left with limesdr-usb, but the generic issue is solved.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=197622020-09-30T20:08:53Zlaforge
<ul><li><strong>Assignee</strong> deleted (<del><i>roh</i></del>)</li></ul> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=197692020-09-30T20:09:29Zlaforge
<ul><li><strong>Status</strong> changed from <i>In Progress</i> to <i>Stalled</i></li></ul> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=223592021-07-07T13:23:52Zdefog
<ul><li><strong>File</strong> <a href="/attachments/4688">lms_set_band.patch</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/4688/lms_set_band.patch">lms_set_band.patch</a> added</li></ul><p>Hello.</p>
<p>I faced the same issue. When I launch osmo-trx-lms I get very low signal, almost indistinguishable from background noise (unfortunately I can't measure it's power, I dont have any special tools, so I just use RTL-SDR to watch the signal just in front of LimeSDR antenna).</p>
<p>In the log I see the next:<br /><pre>
Wed Jul 7 16:04:15 2021 DTRXCTRL <0002> Transceiver.cpp:877 [chan=0] command is 'SETPOWER 0'
Wed Jul 7 16:04:15 2021 DDEV <0005> LMSDevice.cpp:601 [chan=0] Setting TX gain to 2.38195e+190 dB (~5.77761e+228 dBm)
</pre><br />It looks like there is garbage in variable, used for setting Tx power.</p>
<p>After digging in sources for half an hour I noticed, that in Transceiver52M/device/lms/LMSDevice.cpp LMSDevice::band_desc field is uninitialized when setting the power, so I added it's initialization. Suggested patch is in attachment. Don't know how relevant this patch is, but it fixes the problem.</p>
<p>Regards, Andrew.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=223712021-07-08T20:55:50Zlaforge
<ul><li><strong>Assignee</strong> set to <i>Hoernchen</i></li></ul><p><a class="user active" href="https://osmocom.org/users/52">Hoernchen</a>, please have a quick look. If the patch looks fine, please submit to gerrit.</p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=223832021-07-11T19:15:35ZHoernchen
<ul></ul><p>Fixed by <a class="external" href="https://gerrit.osmocom.org/c/osmo-trx/+/24910">https://gerrit.osmocom.org/c/osmo-trx/+/24910</a></p> OsmoTRX - Bug #3342: osmo-trx-lms: low tx output power levelhttps://osmocom.org/issues/3342?journal_id=238692022-04-06T09:25:06Zfixeria
<ul></ul><p>Hoernchen wrote in <a href="#note-20">#note-20</a>:</p>
<blockquote>
<p>Fixed by <a class="external" href="https://gerrit.osmocom.org/c/osmo-trx/+/24910">https://gerrit.osmocom.org/c/osmo-trx/+/24910</a></p>
</blockquote>
<p>The patch has been merged months ago. Can we close this ticket now?</p>