This study proposes amplitude limiting type spread spectrum communication to be applied to extremely low power radio wave communication and evaluates the capability of code division multiplexing. First, changes in output from the correlation device, maximum power, and in allowable noise power are compared by computer simulation for the case where the number of multiplexed channels is increased. Second, a possible relationship between noise intensity and error rate is measured by actual loading experiments using a device developed for trial purposes. Third, majority decision logic is proposed for the said device to realize amplitude limiting type code division multiplexing easily. It is revealed that, in the spread spectrum, alteration of the number of multiplexed channels is made easy by application of this method.

http://ieeexplore.ieee.org/iel4/5224/14121/00647157.pdf

An amplitude limiting type code division multiplex system for extremely low power transmitters

Multinomial representations are derived for majority logic operations on bipolar binary data. The coefficients are given simply in terms of the readily computed lower Cholesky factor of Pascal matrices of order n for codes of block length n

/pdf/multinomial-representation-of-majority-logic-coding-ttyr5m2rbo.pdf

Multinomial representation of majority logic coding

CMOS Majority Circuit with Large Fan-In

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.

T. Maseng

Papers

Performance Analysis of a Majority Logic Multiplex System