Enhanced CCK modulation in wireless LAN with contention free

It is well known that contention is unavoidable in WLAN based on IEEE 802.11 when two users send data simultaneously. Because of this, the transmission rate of each user is decreased tremendously. We present a novel enhanced CCK (complementary code keying) modulation scheme based on Ear ZCZ (zero correlation zone) sequences; this scheme gives contention free operation when the system works in approximately synchronization mode. Then the transmission rate of each user can be maintained with almost no interference from other users.