Written by tuzs
Gurevich V., Egorov S.,
Modeling of Amplitude Characteristic in Radio Channels of Code Division Multiple Access Systems
- Abstract: In CDMA radio access systems, amplitude distortions in a nonlinear amplifier (NA) of a group signal lead to bit errors at the outputs of subscriber channels. To assess the permissible distortion limits and their influence on the transmission quality of subscriber signals, an electronic model of the amplitude characteristic (AC) and analytical relations are needed that relate the probability of an error when registering the output signal of the communication channel with the nonlinearity of the AC NA and other destabilizing factors. The article compares alternative mathematical models of AC NA. In contrast to traditional methods of analysis, usually limited to the choice of models with fixed parameters, a method for variably determining the parameters of AC is considered. The results are: a comparison of known methods for approximating the AC of broadband nonlinear power amplifiers of radio signals is given, an algorithm for selecting model parameters for CDMA systems with QAM using the Rapp model is proposed.
- Keywords: code division multiplexing, CDMA, quadrature amplitude modulation, group signal, radio path, nonlinear distortion, amplitude characteristic, power amplifier.