Impact analysis of orthogonal signal errors on network capacity with code division

The technology of Code Division Multiple Access (CDMA) is based on parallel transfer of mutually orthogonal broadband signals that use total available time and frequency band of wireless medium. The errors of inaccurate fulfillment of conditions of mutual signals orthogonality inevitably generate the intra-cell and inter-cell interference noise that define available value of ratio Signal-to-Interference & Noise Ratio (SINR). The SINR value, in turn, limits the maximal number of parallel active code division channels, i.e., the capacity of cellular cell. Usually, SINR values are calculated indirectly through the ratios of energy parameters of broadband signals. However, the indirect approach does not allow considering dependence of the interference versus orthogonality conditions errors. In this paper, the advanced calculation method of the CDMA networks’ capacity is offered, which allows considering the dependences “SINR versus not strict orthogonality errors” directly through the orthogonal signals correlation functions. It is showed, that it is possible raise many times the networks CDMA capacity by reduction of the signals’ orthogonality errors.

CDMA, CDMA, network capacity, code division, orthogonal, noise-type, broadband signals, orthogonal errors, signal/interference noise ratio

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