Re: [Discuss-gnuradio] Automatic Identification System receiver for GR

[Johnathan Corgan]

On Mon, Jul 27, 2009 at 15:33, Nick Foster<address@hidden> wrote:

> Just wanted to let you know I've committed the first version of the AIS
> receiver I wrote to CGRAN. The project home page is at
> http://www.cgran.org/wiki/AIS.

Excellent!  AIS is fascinating in that it uses self-organized TDMA.
Without central coordination, stations will negotiate for broadcast
time slots, and the effective "cell size" automatically adjusts based
on the FM capture properties of GMSK.  It's like a peer-to-peer ad-hoc
MAC protocol and works very well in the maritime environment.

I know your application is receive only, and doesn't need to deal with
any of this, but I've often considered it would be an interesting
experiment to try to replicate this SOTDMA MAC in our digital packet
radio, to replace the crude CSMA MAC we have now.  Unfortunately, the
lack of timed TX/RX and message passing in GNU Radio makes this
difficult, but of course thats what we're working on now for 3.3.

Johnathan