Wifi: struct raw_rx_pkt_header signal values

[Bruno Randolf]

I am receiving packets in monitor mode on a nRF7002DK. I need some advice on how to interpret the signal value. From <modules/nrf_wifi/fw_if/umac_if/inc/system/fmac_structs.h> I get:

struct raw_rx_pkt_header {
   /** Frequency on which this packet received. */
   unsigned short frequency;
   /** Signal strength of received packet. */
   signed short signal;
   /** Received packet type */
   unsigned char rate_flags;
   /** Data rate of the packet (MCS or Legacy). */
   unsigned char rate;
};

What I receive is for example:

1C:57:3E:71:99:E3: BEACON RSSI 23300 freq 2412 rate 1/0 len 22

How do I interpret 23300 as a RSSI value, ideally in dBm?

[Amanda Hsieh]

Hi, 

1C:57:3E:71:99:E3: BEACON RSSI 23300 freq 2412 rate 1/0 len 22

How do you get the log? Which NCS version and sample are you using?

Regards,
Amanda H.

[Bruno Randolf]

This is my own code based on the wifi/monitor sample. NCS version 3.0.1

[Amanda Hsieh]

Could you provide the snipped code for how you received that log? 

[Bruno Randolf]

// #include <modules/nrf_wifi/fw_if/umac_if/inc/system/fmac_structs.h>
struct raw_rx_pkt_header {
    /** Frequency on which this packet received. */
    unsigned short frequency;
    /** Signal strength of received packet. */
    signed short signal;
    /** Received packet type */
    unsigned char rate_flags;
    /** Data rate of the packet (MCS or Legacy). */
    unsigned char rate;
};

static void parse_packet(unsigned char* packet, int len)
{
    if (len < sizeof(struct raw_rx_pkt_header)) {
        LOG_ERR("Invalid size");
        return;
    }

    struct raw_rx_pkt_header* hdr = (struct raw_rx_pkt_header*)packet;
    packet += sizeof(struct raw_rx_pkt_header);

    uint8_t* ta = uwifi_get_80211_header_ta(packet, WIFI_SCAN_PKT_SIZE);
    if (!ta) {
        return;
    }

    uint16_t fc = uwifi_get_80211_header_fc(packet, WIFI_SCAN_PKT_SIZE);

    LOG_INF("SCAN " MAC_FMT ": %s RSSI %d freq %d rate %d/%x len %d",
            MAC_PAR(ta), wlan_get_packet_type_name(fc), hdr->signal,
            hdr->frequency, hdr->rate, hdr->rate_flags, len);
}