Send analog value over IR? for my rc robot I want to use ir to send/receive the value from a jostick.

Is it possible ? I can't use any other radio chip like nrf24l01.
Yes, it is possible. That is already supported by the IR library. Please see this tutorial for further details. The outline of the sender is:

 uint16_t sample = analogRead(A0);
 irsend.sendSony(sample, 16);


And the receiver:

 if (irrecv.decode(&amp;decodedSignal)) {
    uint16_t sample = decodedSignal.value;
    ...
 }


Cheers!