What to contact through air ?

Hi !!
I am working on a robot and i need to control it through wireless communication, at first i thought to use a R.F. module for it but the area where i m going to finally present my work will have many more bots and many more R.F. modules which may cause noise problem and control failure . please suggest me what should i do ?
I was also thinking to use DTMF but i have read that DTMF is based on the length of the TONE so i was wondering will make the operation of bot much slower ?

You should be able to use RF as long as everybody is on a different frequency.

thank you sir , but what will you say about DTMF ?

I've never used DTMF, but it's an audio-frequency protocol for transmission over telephone lines, not 'through the air', as far as I know. I would think you would get a LOT more interference trying to use audio in a crowded room than trying to find a clear RF channel.

Sir,
i wished to use my cellphone as dtmf transmitter and receiver so as to make it communicate through air and for dtmf , i wish to use MT8870 dtmf decoder and the datasheet have a text saying "Following the filter section is a decoder employing digital counting techniques to determine the frequencies of the incoming tones and to verify that they correspond to standard DTMF frequencies. A complex averaging algorithm protects against tone simulation by extraneous signals such as voice while providing tolerance to small frequency deviations and variations"
more over , i can detach the mikes of the cell phone leaving there ports open so as to stop any human voice noise.
but about dtmf, i read some where that it considers the length of the tone and hence if i am right in my understanding, then since the length of the tone is considered the data transfer rate will be really slow.
About rf, there are only few discrete frequencies at which they work and in my country, i think not even half of them would be available so at the competition area, i just dont want my bot to fail due to rf noise .

Ah, I think I understand now. You are not transmitting DTMF, you are transmitting CDMA, or some other cellphone method. It is still RF. DTMF is encoded into the cell phone signal. But you are correct, DTMF requires a fairly long tone, maybe one-half second.

well dude, I am using ZigBee modules for wireless communication provided by NEX robotics and its very good.

where everybody only use diffrent frequency can still to noise.
i think, you should use a wilesst modul and sigin by pass.