Wideband Code-Division Multiple Access (W-CDMA), also known as IMT-2000, is a 3rd generation wireless technology. Supports speeds up to 384Kbps on a wide-area network, or 2Mbps locally.

Wireless Datagram Protocol (WDP) works as the transport layer of WAP. WDP processes datagrams from upper layers to formats required by different physical datapaths, bearers, that may be for example GSM SMS or CDMA Packet Data. WDP is adapted to the bearers available in the device so upper layers don't need to care about the physical level.

Developed by Nortel Networks, Universal Mobile Telecommunications Service (UMTS) is a standard that will provide cellular users a consistent set of technologies no matter where they are located worldwide. UMTS utilizes W-CDMA technology.

Personal Communications Service (PCS) is a suite of second-generation, digitally modulated mobile-communications interfaces that includes TDMA, CDMA, and GSM. PCS serves as an umbrella term for second-generation wireless technologies operating in the 1900MHz range.

Also know as IS-95, CDMAOne is a 2nd generation wireless technology. Supports speeds from 14.4Kbps to 115K bps.

Code-Division Multiple Access (CDMA) is a cellular technology widely used in North America. There are currently three CDMA standards: CDMA One, CDMA2000 and W-CDMA. CDMA technology uses UHF 800Mhz-1.9Ghz frequencies and bandwidth ranges from 115Kbs to 2Mbps.

Advanced Mobile Phone Service (AMPS) is a first-generation analog, circuit-switched cellular phone network. Originally operating in the 800 MHz band, service was later expanded to include transmissions in the 1900 MHz band, the VHF range in which most wireless carriers operate. Because AMPS uses analog signals, it cannot transmit digital signals and cannot transport data packets without assistance from newer technologies such as TDMA and CDMA.

TDMA-FS.

CDMA stands for Code Division Multiple Access. It is a channel access method. It employs spread spectrum technology (Direct Spread Spectrum).
Transmitter Side:
In CDMA, a narrowband message signal is multiplied by a very large bandwidth signal celled the spreading signal. This spreading signal is a Psuedo Noise Code signal. All users in CDMA system use the same carrier frequency and may transmit simultaneously. Each user is identified by it's own psuedorandom codeword. This psuedorandom codeword is orthogonal to one another. In this way, each user is separated from the others.

Receiver Side:
For detecting the message signal, the receiver needs to know the codeword used by the transmitter.