Re: [Discuss-gnuradio] How to detect collision when two packets are transmitted simultaneously from two transmitters.

[Tom Rondeau]

On Mon, Nov 11, 2013 at 9:33 AM, Aditya Dhananjay <address@hidden> wrote:
>> 1. I tried checking for the average power but that doesn't work. Even with
>> two transmitters transmitting at the same time the energy detected by the
>> receiver doesn't change much. It remains in the same order.
>
>
> It is expected behavior to be in the same order. Try looking at the received
> power in absolute (not dB) scale.


Even that's not likely to work because of the variations in wireless
channels. This is why 802.11 uses CSMA/CA (collision avoidance)
instead of the 802.2 CSMA/CD (collision detection). You can do things
on wired channels that you can't on wireless ones. The collision
avoidance is to do the carrier sensing and combine it with RTS/CTS to
help with avoiding collisions. When not using RTS/CTS, you have to
rely on higher layers to detect a missing packet and/or out of order
packets and request retransmission or just fail to ACK.

Fundamentally a very hard problem.

Tom