a unique time offset of its pilot PN code. The timing is coordinated through global positioning system (GPS) radios at the base stations. 6 These offsets are in increments of 64 chips, so there are 512 unique offsets. At the speed of light, about 300,000 km/s, these offsets work out to 15.6 km. Only the busiest systems have SO many cells that there is confusion among pilots at the user terminal. This confusion oc- curs in regions where a user terminal detects so many pilots that it does not reliably identify the best signal. We will have more to say about this in Sec. 30.1. 10.2 cdma2000 cdma2000 standards development is being promoted by the CDG. CDG is attempting to deliver a series of incremental standards that provide a smooth, quick migration from cdmaOne to cdma2000. The first versions are referred to as cdma2000 1x. The 1x describes the carrier bandwidth as a ratio to the 1.25-MHz bandwidth of cdmaOne. cdma2000 systems now being deployed are all 1x, with 3x expected later. cdma2000 adds data services, starting at about 144 kbps, and also has the potential to double the voice capacity of cdmaOne networks. In deploying cdma2000 1x systems, vendors hope to achieve the following objectives: Increased voice capacity Added or enhanced data capacity Installation of software-upgradeable cdma2000 equipment, which will reduce the cost of upgrading to later cdma2000 standards Support for cdma2000 and cdmaOne user terminals on the same carrier frequency GPS systems, in addition to providing timed triangulation allowing a receiver to determine its exact location, also provide a readily available synchronized clock service. 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 Worldwide CDMA Standards The cdma2000 standard will doubtless go through a number of modifications, as all standards do. As of the time of publication, the