This is a general purpose remote control project with using programmable PIC microcontrollers. Schematics are shown for using infrared (RF) or radio (RF) media. If you are not familiar with microcontroller programming, you can use fixed encoder and decoder integrated circuits instead. Well-known such IC-s are Holtek HT-12D, HT-12E and Motorola MC145026, MC145027, MC145028.
http://jap.hu/electronic/codec.html
A modern RC encoder, whether it be for an AM or FM system, would typically produce of a number of pulses corresponding to the number of channels, plus a longer sync pulse to enable the decoder at the receiver end to extract the pulses in the correct order.
http://users.picbasic.org/projects/RcEncoder/radio_control_encoder.htm
It was first published in two parts in the July and October 1948 editions of the Bell System Technical Journal
http://cm.bell-labs.com/cm/ms/what/shannonday/paper.html