CDMA2000 Downlink and Uplink Comparison

The CDMA2000 downlink has not changed significantly from cdmaOne (IS95). There
is one forward fundamental channel (F-FCH) and up to eight forward supplemental
code channels (for RC2).
The uplink is significantly different because of the decision that handsets should be
capable of transmitting more than one code simultaneously (a multicode uplink). This
requires a reverse pilot (R-Pilot + power control), which allows the base station to do
synchronous detection, and a reverse fundamental channel (R-FCH) for voice. Other
supplemental channels (R-SCH) can be added in as required. The RDCCH (reverse
dedicated control channel) is used to send data or signaling information. The channels
can be assigned to either the I or the Q path and then complex-scrambled to generate
the HPSK signal for modulation, to reduce the peak-to-average ratio.