cck - Computer Definition
In IEEE 802.11b wireless LANs (WLANs), a process that organizes data bits into a series of complementary sequences that form 64 unique six-bit code words. Differential quaternary phase-shift keying (DQPSK) then modulates the code bits to form complex bit pairs known as chips, eight of which form a symbol, which is the smallest CCK transmission unit. In 802.11b WLANs operating at 5.5 and 11 Mbps, the symbol rate is 1.375 MSps and the chip rate is 11 Mchips per second. At 5.5 Mbps, 4 data bits are mapped into the 8 chips of each symbol. At 11 Mbps, 8 data bits are mapped into the 8 chips of each symbol. See also 802.11b, chip, DQPSK, encode, IEEE, modulate, symbol, and WLAN.
(Complimentary Code Keying) A direct sequence spread spectrum (DSSS) coding method used in the 802.11b wireless LAN standard for 5.5 and 11 Mbps. The slower 1 and 2 Mbps specifications use Barker coding which has a chip rate of 11 compared to 8 in CCK. CCK also provides up to 64 coding patterns, whereas Barker uses only one. Unlike CDMA, which overlaps transmissions using different codes, CCK uses the different codes to transmit more data serially (TDM). Contrast with OFDM. See CCK/OFDM and chip rate.