{"id":734,"date":"2018-05-04T09:55:12","date_gmt":"2018-05-04T09:55:12","guid":{"rendered":"http:\/\/open-cells.com\/?p=734"},"modified":"2024-08-19T10:03:28","modified_gmt":"2024-08-19T10:03:28","slug":"limesdr-new-set-of-tests","status":"publish","type":"post","link":"https:\/\/open-cells.com\/index.php\/2018\/05\/04\/limesdr-new-set-of-tests\/","title":{"rendered":"LimeSDR new set of tests"},"content":{"rendered":"

We use the latest commit in https:\/\/github.com\/myriadrf\/LimeSuite.git<\/p>\n

Ubuntu 18.04<\/p>\n

LimeSDR (HW: V1.4) flashed with latest firmware (Limeutil –update)<\/p>\n

Scope: LTE SISO downlink signal<\/p>\n

We use a custom OpenAirInterface version<\/p>\n

The LimeSDR interface code is:<\/p>\n

LMS_Open(&lms_device,list[0],NULL);\r\n LMS_Init(lms_device);\r\n LMS_Reset(lms_device);\r\n\r\nLMS_EnableCalibCache(lms_device,false);\r\n LMS_LoadConfig(lms_device, );\r\n LMS_SetSampleRate(lms_device,4), \u201c\u201d); \/\/rate is LTE standard one, so a division of 30720MS\/s\r\n LMS_SetLOFrequency(lms_device,LMS_CH_RX, 0); \/\/ several feq tested 700MHz-3600MHz\r\n LMS_SetLOFrequency(lms_device,LMS_CH_TX, 0); \/\/ Tx\/Rx freq are different, gap is defined by 3GPP\r\n LMS_SetGaindB(lms_device, LMS_CH_TX, 0, MyGain);\r\n LMS_SetGaindB(lms_device, LMS_CH_RX, 0, MyGain);\r\n \/\/value is 0\u202670, we saw the today limitation: it is not actually in dB, but still the range is 0\u202670\r\n LMS_SetLPFBW(lms_device,LMS_CH_RX,0,ChosenLTEBand); \/\/ 5MHz or 10MHz or 20MHz\r\n LMS_SetLPFBW(lms_device,LMS_CH_TX,0,ChosenLTEBand);\r\n LMS_Calibrate(lms_device,LMS_CH_RX,0,ChosenLTEBand,0);\r\n LMS_Calibrate(lms_device,LMS_CH_TX,i,ChosenLTEBand,0)<\/pre>\n
First observation is: the API calls often fails: calibration reports failures<\/p>\n
With some ini files, it is simply impossible to run successfully the above sequence.<\/p>\n
With “good” ini files, we have to power-off the board before each trial.<\/p>\n
The key problem is to make a decent .ini file, that is good only in a specific case: RF band, modulated band, power, …<\/p>\n
Then, even with a good ini file, the result of the calibration is not repeatable, and often fails randomly (need to power off the LimeSDR board).<\/p>\n
Measuring this DL signal<\/p>\n
A USRP B210 output:<\/p>\n
\"\"<\/p>\n
The best of LimeSDR can be close to this<\/p>\n
\"\"<\/p>\n
Even in this best result, the DC offset is not well calibrated<\/p>\n
Also it is not repeatable, and depend heavily of the .ini file we use<\/p>\n
\"\"<\/p>\n
or non repeatable results<\/p>\n
\"\"<\/p>\n
At lower frequency, LimeSDR is globally better<\/p>\n
\"\"<\/p>\n","protected":false},"excerpt":{"rendered":"
We use the latest commit in https:\/\/github.com\/myriadrf\/LimeSuite.git Ubuntu 18.04 LimeSDR (HW: V1.4) flashed with latest firmware (Limeutil –update) Scope: LTE SISO downlink signal We use a custom OpenAirInterface version The LimeSDR interface code is: LMS_Open(&lms_device,list[0],NULL); LMS_Init(lms_device); LMS_Reset(lms_device); LMS_EnableCalibCache(lms_device,false); LMS_LoadConfig(lms_device, ); LMS_SetSampleRate(lms_device,4), \u201c\u201d); \/\/rate is LTE standard one, so a division of 30720MS\/s LMS_SetLOFrequency(lms_device,LMS_CH_RX, 0); \/\/ … Continue reading “LimeSDR new set of tests”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_crdt_document":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-734","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/posts\/734","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/comments?post=734"}],"version-history":[{"count":7,"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/posts\/734\/revisions"}],"predecessor-version":[{"id":748,"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/posts\/734\/revisions\/748"}],"wp:attachment":[{"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/media?parent=734"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/categories?post=734"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/open-cells.com\/index.php\/wp-json\/wp\/v2\/tags?post=734"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}