Data transmission method in wireless LAN, access point device and station device

A data transmission method for transmitting data from a station on a wireless local area network, the method comprising:

• receiving information on a contention free period (CFP) in which a channel use right is obtained through polling and information on a high-throughput (HT) contention period in which HT stations obtain a channel use right through contention, from an access point;
• allocating a sub-contention free period (Sub-CFP) in which legacy stations and HT stations having multiple antennas are polled and obtain a channel use right with a length of at least one of the contention free period and the HT contention period;
• and
• if a sub-contention free period termination message indicating a termination of the sub-contention free period is received from the access point before the sub-contention free period expires, obtaining a channel use right through contention among the HT stations,
• wherein the sub-contention free period termination message is received only by the HT stations, and
• wherein at least one of the receiving, the allocating, and the obtaining is performed using a processor of the station on the wireless local area network.

An access point on a wireless local area network comprising:

• a high-throughput contention period allocation unit which allocates a sub-contention free period (Sub-CFP) in which legacy stations and LIT stations with multiple antennas obtain a channel use right through polling, and an HT contention period in which the LIT stations obtain a channel use right through contention, in a contention free period (CFP) where a channel use right is obtained through polling;
• and
• a Sub-CFP adjusting unit which transmits a Sub-CFP termination message indicating a termination of the Sub-CFP, to the HT stations before the Sub-CFP expires,
• wherein the Sub-CFP termination message is received only by the HT stations.

A station on a wireless local area network comprising:

• a frame reception unit which receives information on a contention free period (CFP) in which a channel use right is obtained through polling and information on a high-throughput contention period in which HT stations obtain a channel use right through contention, from an access point;
• a sub-contention free period (Sub-CFP) allocation unit which allocates a Sub-CFP in which legacy stations and HT stations having multiple antennas are polled and obtain a channel use right with a length of at least one of the CFP and the HT contention period;
• and
• a contention performing unit which obtains a channel use right through contention among the HT stations if a Sub-CFP termination message indicating a termination of the Sub-CFP is received from the access point before the Sub-CFP expires,
• wherein the Sub-CFP termination message is received only by the HT stations.