文档介绍：3G CDMA - WCDMA and cdma2000
Rodger E. Ziemer
munications Society
Distinguished Lecturer Program
May 28-June1, 2001
1
R. Z. Ziemer, Colorado Springs, CO
Rules for Efficient Multiple Access
Three laws
Know the channel
Minimize interference to others
Mitigate interference received from others
Requirements of wireless multiple access
Channel measurement
Channel control and modification
Multiple user channel isolation
May 28-June1, 2001
2
R. Z. Ziemer, Colorado Springs, CO
Why CDMA?
Higher capacity
Improved performance in multipath by diversity
Lower mobile transmit power = longer battery life
Power control
Variable transmission rate with voice activity detection
Allows soft handoff
Sectorization gain
High peak data rates can be bats other-user interference = lower reuse factors
May 28-June1, 2001
3
R. Z. Ziemer, Colorado Springs, CO
What is Third Generation? [1]
Flexible support of multiple services
Voice
Messaging – email, fax, etc.
Medium-rate multimedia – access, educational
High-rate multimedia – file transfer, video
High-rate interactive multimedia – video telecon-ferencing, telemedicine, etc.
Mobility: quasi-stationary to high-speed platforms
Global roaming: ubiquitous, seamless coverage
Evolution from second generation systems
May 28-June1, 2001
4
R. Z. Ziemer, Colorado Springs, CO
W-CDMA Versus cdma2000 [2]
May 28-June1, 2001
5
R. Z. Ziemer, Colorado Springs, CO
WCDMA Uplink Frame Structure [1]
DPDCH
I: data channel
Q: sync & control
H
Pilot:
TFCI
FBI
TPC
TFCI = transmit bination indicator
FBI = feedback information
TPC = transmit power control
DPDCH = dedicated physical data channel
H = dedicated physical control channel
slot 0
slot 1
slot i
slot 14
radio frame = 10 ms
May 28-June1, 2001
6
R. Z. Ziemer, Colorado Springs, CO
WCDMA Uplink Modulator Structure [1]
pulse shape
filter (SRC)
pulse shape
filter (SRC)
DPDCH1
DPDCH2
DPDCH3
H
I
Q
+
+
+
-
+
+
May 28-June1, 2001
7
R. Z. Ziemer, Colorado Springs, C