 together to offer subscribers packet-switched data service with rates as high as 64 kbps using RS1 and 115 kbps using RS2. 29.3.2 Data over data links Packet data service on cdmaOne is offered at 9.6 kbps using service option 4103 and at 14.4 kbps using service option 15. The packet links can be active or dormant, SO band- width is not wasted when the data connection is inactive. The packet services of cdmaOne are managed by RLP, SO they can use the air interface at cellular-type BER (sim- ilar to voice calls) and they can deliver data-type BER (around 10-6) to their subscribers. 29.4 3G Data Capacity While third-generation (3G) data capacity measurements will have to wait for 3G sys- tems to go into service, we can estimate 3G data capacity using the same CDMA ca- pacity principles we have been using. Data service takes a bigger bite of the CDMA ap- ple because data subscribers typically want more bits per second than voice calls and because data services demand higher accuracy in those bits. A voice call with one wrong bit per thousand sounds fine, but one wrong pixel in a large graphic file can elicit loud complaints from the person viewing the image. 29.4.1 Normal data speeds There are two kinds of data channels in 3G CDMA, supplemental channels dedicated to particular calls and shared packet channels. Both are administered over a funda- 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. CDMA Data Capacity Principles CDMA Data Capacity Principles mental channel for the data call. For a capacity example, let us use a 32-kbps data link. Let us consider cdma2000 3x, at 3.6844 megachips per second. Wideband CDMA (W-CDMA) at 3.84 megachips per second gives very similar numbers. With a rate 1/3 FEC scheme and QPSK modulation, the W/R value is 38.4. We could consider an 11-kbps data service for a similar 38.8:1 ratio for time division synchronize