Performance Analysis of a Majority Logic Multiplex System

The code division multiplexing (CDM) of digitally modulated baseband signals is normally referred to as majority logic multiplexing (MLM). The employment of MLM techniques in spread spectrum multiple access (SSMA) systems is especially attractive because it allows many different types of baseband channels to be easily combined. The traffic level can be gradually reduced to obtain a desired increase in processing gain, without affecting the active channels´ share of the transmitter power. The code integrity and the processing gain of the SSMA equipment can be preserved by suitable design. This paper contains a general performance analysis of an MLM system that uses random codes. The basic MLM principle is extended to handle the combining of traffic channels with different bit rates. Calculated values of performance deterioration due to noise are compared with experimental results and found to be m close agreement.