Are there any network protocol that we can use at competition?

[EricH]

IIRC, Bluetooth also operates in the 2.4GHZ range; thus, be cautious. I suggest reading T5 as well as T4--they are not kidding about anything in that. The field staff can sniff out networks in the 802.11 band (and other stuff like that)--if they say to shut it off, hit the power switch immediately.

You might be able to use a router that operates in another band entirely. If you can find one. Otherwise, you might want to take a look at the use of cell phone networks, or maybe SneakerNet.