quoted from Network Computing July 10, 2000, p. 46
AMPS (Advanced Mobile Phone Service): This basic analog cellular service in the United States and South America typically operates at 800 MHz and uses FDMA transmission technology. With AMPS, when one person grabs a segment of frequency for a call, nobody else within the cell can use it. Digital cellular technologies offer ways for carriers to allow more calls in a cell, using the same amount of bandwidth.
CDMA (Code Division Multiple Access): The dominate PCS standard in the United States, this spread-spectrum technology, developed by Qualcomm, lets multiple callers share a segment of frequencies.
CDPD (Cellular Digital Packet Data): This packet-based technology allows either 9.6-Kbps or 19.2-Kbps data rates over standard analog channels in the 800- to 900-MHz range, by finding and employing unused channels. AT&T's Wireless IP is an example of a CDPD-based service.
FDMA (Frequency Division Multiple Access): Used in the AMPS system, FDMA is a method of coordinating radio traffic to prevent interference between users sharing a set of frequencies. Only one subscriber can access a given frequency at one time.
GSM (Global System for Mobil Communications): A variant of TDMA, GSM is the closest to a worldwide standard for cellular service. A single-frequency GSM cellular handset may work compatibly in Europe, Asia, India and Africa--though not in the United States.
PCS (Personal Communications Service): PCS refers to the three predominant digital cellular technologies operating in the 1.9-GHz band in the United States: CDMA, GSM and TDMA, all of which can allow data to be sent over cellular networks.
TDMA (Time Division Multiple Access): TDMA is a method of dividing a single analog channel into a number of time slots and assigning each user a distinct time slot within a given channel. This lets more users (usually three) access a channel at one time without interference. TDMA is one of the standard digital cellular technologies, along with CDMA. GSM is a variant.
WAP (Wireless Application Protocol): This network-neutral protocol is used for sending data to and from WAP-capable devices, such as cellular phone handsets.
For explanations of more wireless terms, see www.wirelessdata.org/primer/terms.asp .