Complementary code keying

Complementary code keying (CCK) is a modulation scheme used with wireless networks (WLANs) that employ the IEEE 802.11b specification. In 1999, CCK was adopted to supplement the Barker code in wireless digital networks to achieve data rate higher than 2 Mbit/s at the expense of shorter distance.

Source: Wikipedia — Complementary code keying (CC BY-SA 4.0)