Wireless Ad Hoc and Sensor Networks

Background on Networking 153G W-CDMA (UMTS): Universal mobile telecommunications systems(UMTS) is a visionary air interface standard that was developedby European Telecommunications Standards Institute(ETSI). UMTS was designed to provide a high-capacity upgradepath for GSM. Several other competing wideband CDMA (W-CDMA) proposals agreed to merge into a single W-CDMA standard.The resulting W-CDMA standard is now called UMTS.UMTS: UMTS assures backward compatibility with the second generationGSM, IS-136 technologies. The 3G W-CDMA air interfacestandard had been designed for “always-on” packet-basedwireless service. It supports packet data rates up to 2.048 Mbpsper user. Future versions of W-CDMA will support stationaryuser data rates in excess of 8 Mbps.3G CDMA2000: The cdma2000 vision is to provide a seamless andevolutionary high data-rate upgrade path for current users of2G and 2.5G CDMA technology, using a building block approachthat centers on the original 2G CDMA channel bandwidthof 1.25 MHz per radio channel. The cdma2000 standardis being developed under the auspices of working group 45of the Telecommunications Industry Association (TIA) of theU.S. Cdma2000 1X supports an instantaneous data rate of upto 307 kbps for a user in packet mode, and yields typicalthroughput rates of up to 144 kbps per user, depending on thenumber of users, the velocity of a user, and the propagationconditions.3G TD-SCDMA: The China Academy of Telecommunications Technology(CATT) and Siemens Corporation jointly submitted anIMT-2000 3G standard proposal in 1998, based on time divisionsynchronous code division multiple access (TD-SCDMA). Thisproposal was accepted by ITU as one of the 3G options in 1999.TD-SCDMA relies on the existing core GSM infrastructure. Itcombines TDMA and TDD techniques to provide a data-onlyoverlay in an existing GSM network. Up to 384 kbps of packetdata is provided to data users in TD-SCDMA.Fourth-generation (4G) cellular networks: Broadband applications infuture wireless networks may require data rates that are manytimes the maximum data rate as promised for UMTS. Broadbandservices like wireless high-quality videoconferencing (up to100 Mbps) or wireless virtual reality (up to 500 Mbps, whenallowing free body movements) are envisioned. The goal of thenext generation of wireless systems — the 4G — is to providedata rates yet higher than the ones of 3G while granting the samedegree of user mobility.