Autocorrelation - a new differentiating domain for multiple access wireless communications

Abstract

Existing multiple access methods, such as TDMA, CSMA/CA, FDMA, and CDMA, require transmitters be coordinated in order to assure multiple access signals to be separable based on the difference in time domain, frequency domain, or code domain, respectively. These coordinative multiple access methods may suffer co-channel interferences badly from non-coordinative transmitters. In this paper, a new differentiating domain, the autocorrelation of the transmitted signals, is exploited, and a new random multiple access method, based on the principle of Autocorrelation Matching (AM), is developed on top of it. The advantages of having autocorrelation as the differentiation factor for multiple access communications systems include, among others, (1) one FIR vector filter automatically does both the equalization of the designated FIR channel for the purpose of detecting the desired signal and the suppression of all other signals; (2) no training signal is needed for equalization; and (3) the equalization and suppression performance is independent of the noise level.