Time synchronization of stations

A method for time synchronization of a station (STA) in a wireless local area network, the method being performed by the STA, the method comprising the steps of:

• receiving a request from an access point (AP) for the STA to transmit a response to the AP, the request indicating which frequency sub-band the STA is to use for transmitting the response and transmitted by the AP in response to the AP receiving indications that downlink data is to be transmitted to the STA;
• transmitting the response to the AP in the indicated frequency sub-band, wherein the response comprises orthogonal frequency-division multiple access (OFDMA) symbols;
• and
• receiving control signalling from the AP, the control signalling comprising a time alignment command for the STA, wherein the time alignment command is based on a time delay for the STA determined based on the response.

An access point (AP) for time synchronization of stations (STAs) in a wireless local area network, the AP comprising a processing unit that comprises one or more of a central processing unit (CPU), a multiprocessor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), and a field programmable gate arrays (FPGA), capable of executing software instructions stored in a computer program product, the processing unit being configured to cause the AP to:

• receiving indications that downlink data is to be transmitted to at least two STAs;
• responsive to receiving the indication, transmit a request to the at least two STAs for the at least two STAs to transmit a response to the AP, the request indicating which frequency sub-band each of the at least two STAs is to use for transmitting the response;
• receive the responses to the request from the at least two STAs, wherein each of the responses comprises orthogonal frequency-division multiple access (OFDMA) symbols;
• determine, for each of the at least two STAs, a time delay based on the responses;
• and
• transmit control signalling to the at least two STAs, the control signalling comprising time alignment commands for the at least two STAs, wherein each time alignment command is based on the time delay for one of the at least two STAs.

A station (STA) for time synchronization of the STA in a wireless local area network, the STA comprising a processing unit that comprises one or more of a central processing unit (CPU), a multiprocessor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), and a field programmable gate arrays (FPGA), capable of executing software instructions stored in a computer program product, the processing unit being configured to cause the STA to:

• receive a request from an access point (AP) for the STA to transmit a response to the AP, the request indicating which frequency sub-band the STA is to use for transmitting the response and transmitted by the AP in response to the AP receiving indications that downlink data is to be transmitted to the STA;
• transmit the response to the AP in the indicated frequency sub-band, wherein the response comprises orthogonal frequency-division multiple access (OFDMA) symbols;
• and
• receive control signalling from the AP, the control signalling comprising a time alignment command for the STA, wherein the time alignment command is based on a time delay for the STA determined based on the response.