Rake receiver is
the digital section of a CDMA receiver which permits the phone (or cell) to
separate out the relevant signal from all the other signals. The relevant
signal will be encoded with a known Walsh
Code and
a known phase of the Short
code, and the rake receiver can do this because the
Walsh codes are orthogonal and the Short code is orthogonal to
itself at different offsets. The rake receiver is capable of receiving multiple
signal sources and adding them together using multiple fingers, each
of which has the ability to use a separate phase of the short code and long code and a separate Walsh code if
necessary. Different fingers might track multiple signals from the same cell
(arriving at slightly different times due to multipath) or might track separate cells due to soft handoff.