Multiple-access communication using coded pulse interval modulation

Certain physical transmission devices are particularly suited to pulsed high-peak-power, low-duty-cycle operation. Two important examples are pulsed laser optical transmitters and pulsed microwave transmitters. A convenient modulation for such transmitters is differential pulse position, also known as pulse interval modulation (PIM). This paper describes techniques for accommodating a large number of uncoordinated multiple-access users, each employing coded pulse interval modulation. After a brief description of the modulation technique and the multiple-access channel it creates, fundamental limitations on the number of users and interference levels are established by determining the channel capacity, C, and the complexity parameter, R sub o. The remainder of the paper is devoted to a coding technique which can achieve performance arbitrarily close to R sub o. Theoretical and experimental results on performance and complexity are presented.