 For example, when cdma2000 and W-CDMA shift from CDMA transmission to time division multi- ple access (TDMA) transmission to support higher data rates, they use additional forms of modulation, not only quadraphase phase shift keying (QPSK). 10.1 cdmaOne (IS-95) Qualcomm developed the chipset and proposed the standard that became first ANSI IS-95 and then cdmaOne. ANSI IS-95A was a circuit-switched technology, and it was 1The authors did not invent this terminology. We just have to live with it. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Worldwide CDMA Standards Standards for Cellular Systems TABLE 10.1 Comparison of CDMA Standards cdmaOne cdma2000 W-CDMA TD-SCDMA Assigned spectrum, MHz 869-894 869-894 2110-2170 2110-2170 1930-1990 1930-1990 824-849 824-849 1920-1980 1920-1980 1850-1910 1850-1910 TDD not paired 1900-1920 TDD not paired 2010-2025 Voice users/carrier 15-50 15-100 196 (max.) Speech rate 8/13 k 8/13 k up to 13 k Voice activity 4 levels 4 levels on/off on/off Radio conditions No change No change 8 rate AMR 8 rate AMR Data services 2G (few) Normal data rate 14.4 k 307.2 k (1x) 936 k 384 k Ideal conditions 114 k 2 M (1x) Typical mode FDD/CDMA FDD/CDMA FDD/CDMA TDD/TDMA/CDMA Typical carrier 1.25 MHz 1x 1.25 Mhz 5.0 MHz 1.6 MHz 3x 3.75 MHz Chip rate (Mchip/s) 1.2288 1x 1.2288 3x 3.6864 Modulation QPSK/OQPSK Reverse pilot Separate In channel Midamble Forward power control 800/s 1500/s Reverse power control 800/s 800/s 1500/s Smart antennas Maybe Maybe Maybe Joint detection Cell identification Timing Timing PN code PN code followed by IS-95B, which added support for high-speed packet data. This technology was an innovation of the 1990s, bringing spread spectrum into civilian use for the cellular network. Major North American networks such as Sprint PCS and Verizon Wireless, as well as smaller regional companies and some third-worl