PERFORMANCE OF CODED DIRECT-SEQUENCE SYSTEMS WITH RAKE RECEPTION IN AMULTIPATH-FADING ENVIRONMENT

The probability of error is determined for an uncoded coherent direct- sequence spread-spectrum system with rake reception operating in a spe cular multipath fading environment. Bounds on the probability of error for a convolutionally-coded system are also calculated through the us e of the union bound. The model that is utilized contains a large numb er of paths divided into groups across the signalling interval. The ra ke is assumed to be locked onto the direct path and one strong path fr om each of a subset of the other groups. The probability of error is c alculated using the characteristic function to determine the effect of various system parameters such as the processing gain and the number of rake branches. Comparisons are made with results obtained through t he standard Gaussian assumption. Finally, further analytic results are presented for the rake receiver in the low signal-to-noise ratio limi t.