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CDMA 120 – cdmaOne and CDMA2000 Concepts and Terminology phần 10 pot
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CDMA 120 – cdmaOne and CDMA2000 Concepts and Terminology
Section 8: CDMA2000 Overview
80-13321-1 X11
© 2002 QUALCOMM Incorporated 8-35
CDMA 120
cdma university Section 8-35
Forward Link Operation
Variable rate
(Full, 1/2, 1/4, 1/8)
Scheduled rate
On/off
Full Rate
1/4 Rate
1/2 Rate
Fundamental
Channel
(F-FCH)
Supplemental
Channel 1
(F-SCH1)
Dedicated
Control Channel
(F-DCCH)
Forward Link Operation
The figure above shows the operation of the F-FCH, F-SCH1, and F-DCCH channels. The
scheduled rate of the F-SCH1 varies as a function of time, as does the rate of the F-FCH. In the
example above, the F-DCCH channel is used to schedule the data rate of the F-SCH1 and is
operated in Discontinuous Transmit (DTX) mode.
CDMA 120 – cdmaOne and CDMA2000 Concepts and Terminology
Section 8: CDMA2000 Overview
80-13321-1 X11
© 2002 QUALCOMM Incorporated 8-36
CDMA 120
cdma university Section 8-36
Reverse Link Characteristics
Channels are primarily code multiplexed
– Separate channels used for different Quality of
Service (QoS) and Physical Layer characteristics
Code multiplexed channels are orthogonalized by
Walsh functions and I/Q split so that performance is
equivalent to BPSK
Hybrid Combination of QPSK and Pi/2 BPSK
– By restricting alternate phase changes of the
complex scrambling sequence, power peaking is
reduced (1 dB improvement) and side lobes are
narrowed
Notes