Improving a CDMA radio system with an adaptive antenna array by exploiting multichannel enhancements of an A/D converter

This paper proposes an extension of the scheme of Meurer and Raulefs (see ISSTA 2000, New Jersey, p.641-46) by exploiting the already spread signals as a new base for further spreading. Another set of Walsh-Hadamard code sequences is used to spread the already spread signals at different antenna elements of an adaptive antenna array. These signals are accumulated and then converted by one A/D converter into the digital domain. By carefully selecting the Walsh-Hadamard code sequences the total quantization noise of the A/D converter is reduced. The extension of Meurer et al. scheme allows the use of a less powerful and cheaper A/D converter or it offers, by using the same A/D converter, the option of oversampling. The latter decreases the quantization noise of the A/D converter further.