Dear all, Actually, I realized that the CW value must be assigned in a power of 2, minus 1, e.g., 1,3,7,...,1023. So, CW=0 seems to be equal to CW=1 in the chipset. I tested with above cases and observed the same performance. Am I correct? If so, the below phenomenon is resolved easily. Please give your knowledge to me. Thanks. -- Regards, Jinsung Lee -- -----Original Message----- From: linux-wireless-owner@xxxxxxxxxxxxxxx [mailto:linux-wireless-owner@xxxxxxxxxxxxxxx] On Behalf Of Jinsung Lee Sent: Sunday, September 20, 2009 1:43 PM To: linux-wireless@xxxxxxxxxxxxxxx Subject: Question about carrier sensing Hi, all. I'm experimenting using MadWifi driver and Wistron CM6/CM9 cards, which all use the Atheros chipset. But, I found that there is some strange phenomenon on carrier sensing, which doesn't follow the standard. I let the two nearby transmitters just transmit the packets: one transmitter has zero cw value and the other has positive cw values: 10, 100, 1000 where cw is the maximum contention window size, thus the device selects the backoff counter randomly from [0, cw]. If the carrier sensing really works, we would observe that the transmitter with zero cw value takes all while the other don't at all, right? Interestingly, the experimental result shows that the transmitter with positive value has very infrequent but chances to transmit once in a while during the whole experiment, and further the larger cw value, the much less chance the transmitter has to transmit. So, it seems to work though. Do you have any idea or similar experience? Thanks. -- Regards, Jinsung Lee -- -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
