Hello,
my setup consists of 2 NUCLEO-WL55JC1 boards and an adapted version of the example project SubGHz_Phy_Per with which I can recognize the number of bit errors, RSSI of the latest received packet and some interrupts (IRQ_RX_DONE, IRQ_PREAMBLE_DETECTED, ..) using Serial Wire Viewer and STMViewer.
Modulation is 2GFSK.
Tx-Node sends every 10 ms a packet with 80 bytes.
Overview of modulation and packet parameters:
- RF_FREQUENCY: 868000000 /* Hz */
- TX_OUTPUT_POWER: 14 /* dBm */
- FSK_FDEV: 74680 /* Hz */
- FSK_DATARATE: 149360 /* bps */
- FSK_BANDWIDTH: 300000 /* Hz */
- FSK_PREAMBLE_LENGTH: 12 /* Byte, Same for Tx and Rx */
- FSK_FIX_LENGTH_PAYLOAD_ON: true
- PAYLOAD_LEN: 80 /* Byte */
- ModulationShaping: RADIO_FSK_MOD_SHAPING_G_BT_1
- PreambleMinDetect: RADIO_FSK_PREAMBLE_DETECTOR_08_BITS
- whiteSeed: 0x01FF; /*WhiteningSeed*/
- SyncWord: { 0xC1, 0x94, 0xC1}
- CrcLength: RADIO_FSK_CRC_2_BYTES_IBM
- CrcPolynomial: 0x8005
- CrcSeed: 0xFFFF
- Whitening: RADIO_FSK_DC_FREEWHITENING
- StopTimerOnPreambleDetect: 0
- AddrComp: RADIO_FSK_ADDRESSCOMP_FILT_OFF
My calculations of Rx BW and Tx Fdev refer to Semtech SX1261/2 RF Transceiver Datasheet (p.43, LoRa Connect Transceiver, SX1261, +15dBm for Global Coverage | Semtech).
(2*Fdev + BR) < BW
I am aware that the bit error rate depends on the SNR. I don't understand why numerous packet losses occur, even over short distances (indoor) and acceptable RSSI, screenshot from STMviewer:
Packet Loss increases for much too small or large BW, which is understandable.
What possible mistakes have I made?
If you need further information, I can of course add it.
