NDA versus DD multipath delay estimation in wideband CDMA systems
Elena Simona Lohan, Markku Renfors · 2002
We investigate the performance of two delay estimation algorithms, non-data aided (NDA) and decision-directed (DD), in the presence of multipath fading and additive Gaussian noise. The comparison is made assuming perfect knowledge about the amplitudes and phases of channel multipaths, in order to see the maximum achievable performance with these two algorithms. The results indicate that NDA delay estimation offers but little degradation of performance compared to DD algorithm and has the advantage of a reduced complexity and higher spectral efficiency. We also study the impact of data errors on DD delay estimation. The algorithms are applied for a downlink wideband CDMA (WCDMA) system, using Walsh spreading codes and long Gold scrambling codes.