Increasing range of DW3000 in NLOS

We are using DWM3000 modules for our project. the transmission distance we get from DW3000 using channel 9 in LOS condition is more than 100 meters but in NLOS condition(one person is standing very close to the transmitter and blocking the LOS) we are getting only 12 meters, How can we increase transmission distance in such NLOS condition.

Hi,PREDATOR
What is the config do you use? like this:
static dwt_config_t config = {

    5,               /* Channel number. */

    DWT_PLEN_128,    /* Preamble length. Used in TX only. */

    DWT_PAC8,        /* Preamble acquisition chunk size. Used in RX only. */

    9,               /* TX preamble code. Used in TX only. */

    9,               /* RX preamble code. Used in RX only. */

    1,               /* 0 to use standard 8 symbol SFD, 1 to use non-standard 8 symbol, 2 for non-standard 16 symbol SFD and 3 for 4z 8 symbol SDF type */

    DWT_BR_6M8,      /* Data rate. */

    DWT_PHRMODE_STD, /* PHY header mode. */

    DWT_PHRRATE_STD, /* PHY header rate. */

    (129 + 8 - 8),   /* SFD timeout (preamble length + 1 + SFD length - PAC size). Used in RX only. */

    DWT_STS_MODE_OFF, /* STS disabled */

    DWT_STS_LEN_64,   /* STS length see allowed values in Enum dwt_sts_lengths_e */

    DWT_PDOA_M0      /* PDOA mode off */

};

static dwt_txconfig_t txconfig_options ={

0x34,            /* PG delay */

0xffffffff,      /* TX power */

0x0              /* PG count */

};