Communication between RAK2245 and SX1276

Hi. Currently, I’m going to project communication between RAK2245 and SX1276.
I’m using test_loragw_hal.c cord in HAL driver cord and from RAK2245 to SX1276 transmission test is OK!!
But, from SX1276 to RAK2245 transmission test is fail…
I think that need to adjust options in RAK2245 like preamble option or bandwidth or others…
But, I don’t know where these options and how to adjust these options.

I guess my problem is RAK2245 can’t find preamble signal from SX1276.

  1. RAK2245 ==> SX1276
    I know that adjust these options when from RAK2245 to SX1276 transmission.
  2. SX1276 ==> RAK2245

    Maybe, I think that need to adjust lgw_rxif_conf_s(ifconf) structure.
    I don`t understand datarate option and freq option and what value should I put these configuration.

Please help me…