In Code Division Multiple Access( CDMA) and Wideband Code Division Multiple Access(WCDMA), the transmission speed is referred to as the chip rate or symbol rate. It is a measure of the coding speed at which the chips, i.e. the coding elements, convert the signals. The chip rate is specified in chips per second (c/s or cps), or the dimension is given a prefix.
The higher the chip rate, the greater the transmission rate and the resulting bandwidth of the transmitted signal. The quotient of chip rate (c/s) and bit rate (bit/s) is the spreading factor in spread spectrum technology.
In the case of WCDMA or UMTS, the chip rate is fixed and is 3.84 megachips/s (Mc/s) in the 5 MHzfrequency band. CDMA, on the other hand, operates with 1.25 MHz wide frequency bands, which allow a chip rate of 1.2288 MChips/s. Since CDMA can use multicarrier technology with up to three frequency carriers, the chip rate increases to 3.6864 MegaChips/s, which is almost the same as for W-CDMA. Much higher chip rates of several GigaChips per second (Gc/s) are achieved with Direct Sequence UWB( DS-UWB).