Error rate more important in Long range 125k than in normal mode 1M

[David]

We made the test with your demo SDK on the board :

                PCA10056 1.0.0 2018.46
                PCA10056 1.1.0 2019.26

We modify the code to gate the trace ( see the attach file)radio_test-1.zip

And the result are that in 1 Mbits (NO long range) this quite perfect , in Long range 125Kbit we have between 3 and 4 over 1000 packet lost !!!

Do you know how to explain this ?

the details of the results below

Best regards

 

################################
Payload 256
Data rate: RADIO_MODE_MODE_Ble_LR125Kbit
TX power: RADIO_TXPOWER_TXPOWER_Neg20dBm
Transmission pattern: TRANSMIT_PATTERN_11110000
Start Channel:  0
Duty cycle:     50 percent

counter_TX: 29313
counter_CRC_OK: 29227
counter_CRC_ERROR: 0

29227/29313 = 0,997066148


################################
Payload 256
Data rate: RADIO_MODE_MODE_Ble_LR125Kbit
TX power: RADIO_TXPOWER_TXPOWER_Neg8dBm
Transmission pattern: TRANSMIT_PATTERN_11110000
Start Channel:  40
Duty cycle:     50 percent

counter_TX: 10779
counter_CRC_OK: 10774
counter_CRC_ERROR: 1

(10774+1)/10779=0,999628908

################################
Payload 256
Data rate: RADIO_MODE_MODE_Ble_LR125Kbit
TX power: RADIO_TXPOWER_TXPOWER_Neg8dBm
Transmission pattern: TRANSMIT_PATTERN_11110000
Start Channel:    0
Duty cycle:    90 percent

counter_TX: 27706
counter_CRC_OK: 27624
counter_CRC_ERROR: 1

(27624+1)/27706 = 0,997076446

################################
Payload 5
Data rate: RADIO_MODE_MODE_Ble_LR125Kbit
TX power: RADIO_TXPOWER_TXPOWER_Neg8dBm
Transmission pattern: TRANSMIT_PATTERN_11110000
Start Channel:    40
Duty cycle:    50 percent

counter_TX: 37984
counter_CRC_OK: 37977
counter_CRC_ERROR: 0

37977/37984 = 0,99815712

################################
Payload 15
Data rate: RADIO_MODE_MODE_Ble_LR125Kbit
TX power: RADIO_TXPOWER_TXPOWER_Neg8dBm
Transmission pattern: TRANSMIT_PATTERN_11110000
Start Channel:    40
Duty cycle:    50 percent

counter_TX: 26552
counter_CRC_OK: 26548
counter_CRC_ERROR: 0

26548/26552 = 0,999849352

################################
Payload 15
Data rate: RADIO_MODE_MODE_Ble_1Mbit
TX power: RADIO_TXPOWER_TXPOWER_Neg8dBm
Transmission pattern: TRANSMIT_PATTERN_11110000
Start Channel:    40
Duty cycle:    50 percent

counter_TX: 40091
counter_CRC_OK: 40090
counter_CRC_ERROR: 0

40090/40091 = 0,999975057

################################
Payload 256
Data rate: RADIO_MODE_MODE_Ble_1Mbit
TX power: RADIO_TXPOWER_TXPOWER_Neg8dBm
Transmission pattern: TRANSMIT_PATTERN_11110000
Start Channel:    40
Duty cycle:    50 percent


counter_TX: 30934
counter_CRC_OK: 30934
counter_CRC_ERROR: 0

30934/30934 = 1

[bjorn-spockeli]

Hi David, 

as stated in the mail, you'll find the radio_test example with the Errata 191 and 172 workarounds added in the radio_test_orpheo.zip below:

 radio_test_orpheo.zip

I did some tests with both 15 and 256 byte payloads on 125kbit mode and the results look very promising. Note that adding the workaround for errata 172 on the nRF52840 trades away sensitivity for improved selectivity and rejection.

Results from one of the tests:

Payload 256
Data rate: RADIO_MODE_MODE_Ble_LR125Kbit
TX power: RADIO_TXPOWER_TXPOWER_Neg8dBm
Transmission pattern: TRANSMIT_PATTERN_11110000
Start Channel:    0
Duty cycle:    50 percent

counter_TX: 12717
counter_CRC_OK: 12717
counter_CRC_ERROR: 0

12717/12717= 1