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US 9,544,847 B2Granted
Power efficient PS-Poll
AssigneeSTMicroelectronics S.r.l.
InventorsLiwen Chu, George A. Vlantis
Life of this patent
Estimating the term…
Abstract
A IEEE 802.11 Wireless Local Area Network (WLAN) system of an access point (AP) and one or more stations (STAs) reduces power consumption and increases battery life of power efficient low power STAs by decreasing the amount of time that a power efficient low power STA remains in an awake state. After indicating power efficient low power operation during association with an AP supporting such operation, the power efficient low power STA may enter the doze state from the time that the power efficient low power STA sends a PS-Poll until the power efficient low power STA receives the buffered DATA frame from the AP. While implementing the power efficient PS-Poll method, the AP can send the buffered DATA frame to the STA SIFS after the AP sends an ACK to the received PS-Poll from the STA.
Claims28
A method of reducing the power used by a wireless station, the method comprising:
- waking a first wireless station from a doze state to send a PS-Poll frame from the wireless station to an access point;
- in response to the PS-Poll frame being received at the access point, receiving at the first wireless station from the access point an acknowledgement frame containing a traffic buffering bit indicating that traffic for the first wireless station is buffered by the access point and that a data frame is available to transmit to the first wireless station;
- detecting a frame transmitted by a second wireless station that is not for the first wireless station, the second wireless station being different from the access point, after receiving at the first wireless station from the access point the acknowledgement frame indicating that the data frame is available and before receiving at the first wireless station the data frame transmitted by the access point;
- in response to detecting the frame transmitted by the second wireless station that is not for the first wireless station, causing the first wireless station to re-enter the doze state before receiving at the first wireless station the data frame transmitted by the access point;
- waking the first wireless station from the doze state a second time;
- and
- receiving at the first wireless station the data frame transmitted by the access point.
4 more elements
An apparatus that uses reduced power, comprising:
- a controller configured to:
- wake a first wireless station from a doze state and to send a PS-Poll frame to an access point,
- in response to the PS-Poll frame being received at the access point, receive at the first wireless station from the access point an acknowledgement frame containing a traffic buffering bit indicating that traffic for the first wireless station is buffered by the access point and that a data frame is available to transmit to the first wireless station,
- detect a frame transmitted by a second wireless station that is not for the first wireless station, the second wireless station being different from the access point, after the acknowledgement frame indicating that the data frame is available is received and before receiving at the first wireless station the data frame transmitted by the access point;
- in response to detecting the frame transmitted by the second wireless station that is not for the first wireless station, cause the first wireless station to re-enter the doze state before receiving at the first wireless station the data frame transmitted by the access point;
- wake the first wireless station from the doze state a second time;
- and
- receive at the first wireless station the data frame transmitted by the access point.
5 more elements
A method that reduces the power used by a wireless station, the method, the method comprising:
- after receiving an indication that a first wireless station is a power efficient low power wireless station, receiving a PS-Poll frame from the first wireless station at an access point;
- in response to receiving the PS-Poll, transmitting to the first wireless station from the access point an acknowledgement frame containing a traffic buffering bit indicating that traffic for the first wireless station is buffered by the access point and that a data frame containing buffered data for the first wireless station is available to transmit;
- after transmitting to the first wireless station from the access point the acknowledgement frame indicating that the data frame containing buffered data for the first wireless station is available and before transmitting to the first wireless station from the access point the data frame containing buffered data for the first wireless station, receiving a data frame transmitted by a second wireless station at the access point, the second wireless station being different from the first wireless station;
- in response to receiving the data frame transmitted by the second wireless station at the access point, transmitting to the second wireless station from the access point an acknowledgement frame;
- and
- after transmitting to the second wireless station from the access point the acknowledgement frame, transmitting to the first wireless station from the access point the data frame containing buffered data for the first wireless station.
3 more elements
An apparatus that reduces the power used by a wireless station, the apparatus comprising:
- a controller configured to:
- after receiving an indication that a first wireless station is a power efficient low power wireless station, receive a PS-Poll frame from the first wireless station at an access point,
- in response to receiving the PS-Poll, transmit to the first wireless station from the access point an acknowledgement frame containing a traffic buffering bit indicating that traffic for the first wireless station is buffered by the access point and that a data frame containing buffered data for the first wireless station is available to transmit;
- after transmitting to the first wireless station from the access point the acknowledgement frame indicating that the data frame containing buffered data for the first wireless station is available and before transmitting to the first wireless station from the access point the data frame containing buffered data for the first wireless station, receive a data frame transmitted by a second wireless station at the access point, the second wireless station being different from the first wireless station;
- in response to receiving the data frame transmitted by the second wireless station at the access point, transmit to the second wireless station from the access point an acknowledgement frame;
- and
- after transmitting to the second wireless station from the access point the acknowledgement frame, transmit to the first wireless station a data frame containing buffered data for the first wireless station.
4 more elements
Dependencies are inferred from the claim text.