link quality information (ping, getRssiStats, getSnrStats, networkLinkCheck)

[Victor Rocco]

Hi,
i am trying to do a coverage test using an mDot and a mLinux Conduit (915).
I cannot interpret the output data related to link quality and there is no clear documentation.
I am using the mbed library and the mDot.h (https://developer.mbed.org/teams/MultiTech/code/libmDot/file/0b4eb17d07ae/mDot.h)

I have some questions:
1) using getRssiStats(): is there a table correlating RSSI to dBm or mW?
2) using getSnrStats(): is the last result getSnrStats().last or getSnrStats().last/4 ?
3) using ping(): is the snr result ping().snr or ping().snr/10 ?
4) using networkLinkCheck(): is dBm a value from dot->conduit direction or conduit->dot direction?
why it doesn’t match any output value of ping() + getRssiStats() + getSnrStats()? (see the mDot log)

The mDot code i am using is:
============================

dot->send(data);
logInfo(“dot-send: OK!”);

rssi_ret = dot->getRssiStats();
snr_ret = dot->getSnrStats();
logInfo(“rssi %3d, snr (raw %3d) %2d.%02d”, rssi_ret.last, snr_ret.last, snr_ret.last/4, abs(snr_ret.last)%4*25);

ping_ret = dot->ping();
logInfo(“dot->ping: rssi %3d, snr (raw %3d) %2d.%1d”, ping_ret.rssi, ping_ret.snr, ping_ret.snr/10, abs(ping_ret.snr)%10);

rssi_ret = dot->getRssiStats();
snr_ret = dot->getSnrStats();
logInfo(“rssi %3d, snr (raw %3d) %2d.%02d”, rssi_ret.last, snr_ret.last, snr_ret.last/4, abs(snr_ret.last)%4*25);

link_ret = dot->networkLinkCheck();
logInfo(“dot->networkLinkCheck: status [%d], dBm above noise floor [%d], num. gateways [%d]”, link_ret.status, link_ret.dBm, link_ret.gateways);

rssi_ret = dot->getRssiStats();
snr_ret = dot->getSnrStats();
logInfo(“rssi %3d, snr (raw %3d) %2d.%02d”, rssi_ret.last, snr_ret.last, snr_ret.last/4, abs(snr_ret.last)%4*25);

logInfo(“— — — —“);

the mDot log is:
================
[INFO] — — — —
[INFO] dot-send: OK!
[INFO] rssi -61, snr (raw 26) 6.50
[INFO] dot->ping: rssi -63, snr (raw 105) 10.5
[INFO] rssi -57, snr (raw 29) 7.25
[INFO] dot->networkLinkCheck: status [1], dBm above noise floor [27], num. gateways [1]
[INFO] rssi -58, snr (raw 27) 6.75
[INFO] — — — —
[INFO] dot-send: OK!
[INFO] rssi -60, snr (raw 29) 7.25
[INFO] dot->ping: rssi -64, snr (raw 112) 11.2
[INFO] rssi -59, snr (raw 32) 8.00
[INFO] dot->networkLinkCheck: status [1], dBm above noise floor [24], num. gateways [1]
[INFO] rssi -58, snr (raw 29) 7.25
[INFO] — — — —
[INFO] dot-send: OK!
[INFO] rssi -60, snr (raw 36) 9.00
[INFO] dot->ping: rssi -62, snr (raw 98) 9.8
[INFO] rssi -59, snr (raw 31) 7.75
[INFO] dot->networkLinkCheck: status [1], dBm above noise floor [27], num. gateways [1]
[INFO] rssi -58, snr (raw 33) 8.25
[INFO] — — — —

the server (conduit) log is:
============================
root@mtcdt:~# mosquitto_sub -t lora/+/+ -v
lora/00:80:00:00:00:00:a2:e6/joined (null)
lora/00:80:00:00:00:00:a2:e6/up {“chan”:0,”cls”:0,”codr”:”4/5″,”data”:”T0sh”,”datr”:”SF10BW125″,”freq”:”902.3″,”lsnr”:”11″,”modu”:”LORA”,”port”:1,”rfch”:0,”rssi”:-64,”seqn”:0,”size”:4,”timestamp”:”2016-01-28T04:50:42Z”,”tmst”:2571600820}

lora/00:80:00:00:00:00:a2:e6/up {“chan”:4,”cls”:0,”codr”:”4/5″,”data”:”T0sh”,”datr”:”SF10BW125″,”freq”:”903.1″,”lsnr”:”12.2″,”modu”:”LORA”,”port”:1,”rfch”:1,”rssi”:-65,”seqn”:3,”size”:4,”timestamp”:”2016-01-28T04:50:46Z”,”tmst”:2576078148}

lora/00:80:00:00:00:00:a2:e6/up {“chan”:7,”cls”:0,”codr”:”4/5″,”data”:”T0sh”,”datr”:”SF10BW125″,”freq”:”903.7″,”lsnr”:”12.2″,”modu”:”LORA”,”port”:1,”rfch”:1,”rssi”:-66,”seqn”:6,”size”:4,”timestamp”:”2016-01-28T04:50:51Z”,”tmst”:2580556084}

Please, help me with those 4 questions.
Thanks you in advance,
Victor Rocco

• This topic was modified 8 years, 3 months ago by Victor Rocco.

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