Method, access point, server and station used for coordinated transmission

A method for coordinated transmission, comprising:

• transmitting, by a station (STA), an uplink preamble training sequence to an access point (AP), to enable the AP to determine uplink quality information according to the uplink preamble training sequence;
• receiving, by the STA, a null data packet (NDP) transmitted by each AP in a downlink coordinated transmission set, wherein the NDP carries information indicating that a feedback type is coordinated transmission, and the downlink coordinated transmission set is determined by a server according to the uplink quality information;
• measuring, by the STA, downlink channel state information (CSI) according to the NDP;
• transmitting, by the STA, downlink CSI corresponding to the downlink coordinated transmission set to a first AP in the downlink coordinated transmission set;
• and
• receiving, by the STA, data transmitted by the downlink coordinated transmission set through downlink coordinated transmission according to coordinated information, wherein the coordinated information is determined by the server according to the downlink CSI corresponding to the downlink coordinated transmission set.

An access point (AP), comprising:

• a receiving module, configured to receive an uplink preamble training sequence transmitted by a station (STA);
• a determining module, configured to determine uplink quality information according to the uplink preamble training sequence;
• and
• a transmitting module, configured to transmit the uplink quality information to a server, to enable the server to determine a downlink coordinated transmission set according to the uplink quality information.

A station (STA), comprising:

• a transmitting module, configured to transmit an uplink preamble training sequence to an access point (AP), to enable the AP to determine uplink quality information according to the uplink preamble training sequence;
• a receiving module, configured to receive a null data packet (NDP) transmitted by each AP in a downlink coordinated transmission set, wherein the NDP carries information indicating that a feedback type is coordinated transmission, and the downlink coordinated transmission set is determined by a server according to the uplink quality information;
• a measuring module, configured to measure downlink channel state information (CSI) according to the NDP;
• the transmitting module is further configured to transmit downlink CSI corresponding to the downlink coordinated transmission set to a first AP in the downlink coordinated transmission set;
• and
• the receiving module is further configured to receive data transmitted by the downlink coordinated transmission set through downlink coordinated transmission according to coordinated information, wherein the coordinated information is determined by the server according to the downlink CSI corresponding to the downlink coordinated transmission set.