help needed for extracting RSSI information in Cisco Card(airo.c)

Steve J steve_newus at yahoo.com
Wed Mar 26 19:05:23 EST 2003


Hello,
 
  I am trying to extract RSSI (received Signal
Strength Indiacator) from the card using the driver
(airo.c)

  I see two mechanisms in the device driver. Could
someone please tell me which one of the folowing is
right.

1> this is part of the code in airo_interrupt()
corresponding to reception of packet.  
  
    /* Get the rssi signal strength */
                                                      
        bap_setup( apriv, fid, 0x08, BAP0 );
    bap_read( apriv, &rssi, sizeof(rssi), BAP0 );
   apriv->spy_stat[i].level = le16_to_cpu(rssi);
                                                      

    But reading this value gives very strange values.
It increases as the disctance increases ? Also when
near to transmitting station, this value is close to
5-10.

2>  By reading the StatusRid, as in
airo_get_wireless_stats()

     /* Signal quality and co. But where is the
noiselevel ??? */
        local->wstats.qual.qual =
le16_to_cpu(status_rid.signalQuality);
        local->wstats.qual.level =
le16_to_cpu(status_rid.normalizedSignalStrength);
       
    It seems that normalizedSignalStrength is the
RSSI?


Also, I would really apprecite if somebody could tell
me their insight into understanding of three fields of
struct StatusRid i.e. sigQuality, signalQuality,
normalizedSignalStrength. I mean what is unit for
these Quality and Strength fields, and why two fields
for quality ? what do each field represent ?

I remember reading that strength is actually measure
of energy consumtion and quality is measure of SNR. I
dont know if this fits correctly. 

Thanks for your time and considertion

Regards,
-Steve

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