Systems and Methods for Indicating Buffered Data at an Access Point Using a Traffic Indication Map Broadcast
First Claim
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1. A method for indicating buffered data comprising:
- periodically broadcasting a traffic indication map (TIM) frame outside a beacon frame;
said TIM frame comprising a bitmap control field comprising an offset and a partial virtual bitmap field indicative of the stations having buffered data awaiting; and
wherein the broadcasting takes place at a predetermined time.
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Abstract
Stations in standby mode periodically wake up to check for buffered data at the access points. Traditionally, the information is available by checking the periodic beacon frame for a traffic indication map (TIM). Unfortunately, the length of beacons has steadily increased with the progression of the various wireless standards requiring stations to wake up for longer periods to merely check for buffered data. Several approaches are disclosed which address this shortcoming, including the broadcast of TIM frames, the partial reception of beacon frames and the use of an embedded TIM frame within a beacon frame.
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Citations
34 Claims
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1. A method for indicating buffered data comprising:
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periodically broadcasting a traffic indication map (TIM) frame outside a beacon frame; said TIM frame comprising a bitmap control field comprising an offset and a partial virtual bitmap field indicative of the stations having buffered data awaiting; and wherein the broadcasting takes place at a predetermined time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method in a station for retrieving buffered data from an access point comprising:
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waking up at a predetermined time; receiving a TIM frame having a partial virtual bitmap and a check beacon indication; if the partial virtual bitmap is indicative that the access point has buffered data for the station, receiving the buffered data; and if the check beacon indication indicates a critical or significant change in a beacon frame, receiving the beacon frame. - View Dependent Claims (19, 20, 21)
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22. An access point comprising:
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a processor; a wireless network interface device; and a memory comprising instructions; said instructions causing the processor to cause the wireless network interface device to broadcast a TIM frame outside a beacon frame at a predetermined time; and said TIM frame comprising a bitmap control field comprising an offset and a partial virtual bitmap field indicative of the stations having buffered data awaiting. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A station for retrieving buffered data from an access point comprising:
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a processor; a wireless network interface device; and a memory comprising instructions; said instructions causing the processor to wake-up at a predetermined time and to cause the wireless network interface device to receive a TIM frame from an access point having a partial virtual bitmap and a check beacon indication; if the partial virtual bitmap is indicative that the access point has buffered data for the station, to receive the buffered data; and if the check beacon indication indicates a critical or significant change in a beacon frame, to receive the beacon frame. - View Dependent Claims (32, 33, 34)
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Specification