Performance analysis of CDMA signals using orthogonal wavelets as chip waveforms in multipath fading and noisy channels

Orthogonal wavelets are used as chip waveforms for code division multiple access (CDMA) signals, and their probability of errors is investigated in a multipath Rayleigh fading and additive white Gaussian noise channel that is suitable for mobile communication systems. First, the probability of error equation is derived, and it is shown that it depends on the chip waveform. Then, Daubechies wavelets, that are well known orthogonal wavelets, are compared with the conventional chip waveforms, namely raised cosine, half sine and rectangular waveforms, in terms of the above performance measure. It is observed that the error probability performance of Daubechies wavelets is comparable to those of the conventional chip waveforms. Furthermore, the relationship between wavelets and filter banks is utilized to obtain an optimum wavelet that improves the error probability. It is shown that the error probability using the optimum wavelet is better than those using the conventional chip waveforms.