In a time division multiple access communication system, adjacent and co-channel interference are reduced by discontinuing or shutting off modulation of carrier frequency signals during inactive time slots so that transmitted power of carrier frequency signals are reduced. Also, the time slots and carrier frequency signals are organized so that each carrier frequency signal has the least amount of time slots designated as active time slots. The time slots are designated so that the respective same time slots of adjacent carrier frequency signals are not concurrently designated as active time slots.