Hi, I am making efforts to get information from lower layer for wireless link bandwidth prediction.
And I found both madwifi-free and ath5k can directly read from Atheros chip registers.
I have been using several register counters(AR_TXCNT, AR_RXCNT, AR_RCCNT) for a while, and performed several experiments.
Here are my questions:
1. I regard RCCNT(receive clear) as CCA. But I found there are cases when RCCNT(CCA delta) < RXCNT(Receive delta). I conducted my expriments in a controlled environment, The received singal strength of all frames is surelly above CCA threshold. So I feel uncertain about how theses counters increase. Does it have anyting to do with preamble or IFS?
2. Similar problem. When there is only one sender. I found: sender's TXCNT(delta) < receiver's RXCNT(delta). The differnece is only related with frame number. So I guess RXCNT add something more for every received frame. what's that?
Anyone explains the register counters's exactly meaning?
If I got no answer, should I send it to ath5k-dev mailing list or anywhere else?