Filter Design Considerations for Acquisition of BOC-modulated Galileo Signals

In this paper we study the effect of the transition band in designing both FIR- and IIR-types of digital filters, as possible bandwidth-limiting receiver filters, during the CDMA code acquisition of a BOC-modulated and over-sampled Galileo signal. It is shown that using an asymmetric transition band (i.e., the band between the passband and stopband frequencies) with respect to one fourth of the sampling rate, the performance, in terms of root mean square errors (RMSE), can be improved for both FIR and IIR filters compared to the situation with symmetric transition bands. As an optimum bound we have employed the ideal rectangular pulse (i.e. no bandwidth limitation). All investigated filtering methods still suffer from some performance degradation, compared to rectangular shaping. The analysis is done here for both static and fading multipath channels