Method and apparatus for power management in WLAN
First Claim
1. A method for transmitting data in a wireless local area network, the method comprising:
- buffering, at an access point, frames including data to be transmitted to stations capable of operating in a power-saving state;
prior to sending a beacon frame, the access point dividing an interval between beacon frames into a number of time slices; and
transmitting, by the access point, the beacon frame which includes information about a time slice included within the number of time slices when buffered frames destined for particular stations will be sent;
assigning an association identifier to each station and each multicast group associated with the access point, wherein a multicast group is assigned a MAC address;
indicating, in the transmitting step, if there are buffered frames for each station and each multicast group by using the association identifier; and
maintaining a mapping between association identifiers and MAC addresses;
wherein the transmitting step includes transmitting a slicing index providing a relative starting position of the time slices assigned to a destination corresponding to a specific MAC address and a slicing control field which indicates the number of bits in each slicing index.
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Accused Products
Abstract
A method and apparatus for improving power performance of a wireless adapter which adopts a time slicing scheme by dividing a beacon interval into multiple slices, and assigning these slices to the stations through the beacon frame. The stations wakeup at the appointed slices to receive their buffered frames from an access point, and may enter into sleep state once the transactions conclude. A further embodiment including formatting data into a control frame for use in a wireless local area network, the frame including an indication, for each station associated with the wireless local area network, whether frames are buffered awaiting transmission to each respective station, a number of time intervals between control frames, and at which time interval the transmission of the buffered frames will begin for each station having buffered frames awaiting transmission.
25 Citations
18 Claims
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1. A method for transmitting data in a wireless local area network, the method comprising:
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buffering, at an access point, frames including data to be transmitted to stations capable of operating in a power-saving state; prior to sending a beacon frame, the access point dividing an interval between beacon frames into a number of time slices; and transmitting, by the access point, the beacon frame which includes information about a time slice included within the number of time slices when buffered frames destined for particular stations will be sent; assigning an association identifier to each station and each multicast group associated with the access point, wherein a multicast group is assigned a MAC address; indicating, in the transmitting step, if there are buffered frames for each station and each multicast group by using the association identifier; and maintaining a mapping between association identifiers and MAC addresses; wherein the transmitting step includes transmitting a slicing index providing a relative starting position of the time slices assigned to a destination corresponding to a specific MAC address and a slicing control field which indicates the number of bits in each slicing index. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An access point in a wireless local area network, which periodically transmits a beacon frame, the access point comprising:
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a transmitter for transmitting data, including the beacon frame, through the wireless local area network to plural stations; a memory to buffer frames awaiting transmission to the plural stations, which are capable of operating in a power-saving state; and a processor dividing an interval between beacon frames into a number of time slices, and transmitting information about a time slice included within the number of time slices when buffered frames for a respective station will be sent; wherein the processor further includes an indication whether there are buffered frames destined for a station and a time slice control field indicating a number of slices in the interval between beacon frames, and wherein the number of time slices in the interval between the beacon frames is 2n−
1, with n being an integer indicated in the slice control field. - View Dependent Claims (8, 9, 10)
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11. A method of receiving data in a wireless local area network, comprising:
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receiving a beacon frame having information regarding time slices indicating when data associated with a particular station will be transmitted; and determining whether an interval between a current beacon frame and a subsequent beacon frame includes data to be received by the particular station, if so, determining a time slice within the interval that includes the data to be received; maintaining an association identifier list containing one unicast association identifier and an association identifier assigned when joining a multicast group; and comparing a partial virtual bitmap field of a beacon frame with the association identifier list, and if a bit in the partial virtual bitmap field corresponding to the association identifier list is set, then determining the time slice within the interval that includes the data to be received, wherein the determining the time slice within the interval that includes the data to be received further includes; determining from a slicing control field the number of time slices during a beacon interval and a number of bits in each slicing index field; and determining from a slicing index field assigned to the particular station a starting point of the time slice within the interval that includes the data to be received by the particular station. - View Dependent Claims (12, 13, 14)
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15. A station in a wireless local area network, comprising:
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a receiver receiving a beacon frame having information regarding time slices indicating when data associated with the station will be transmitted; and a processor determining whether an interval between a current beacon frame and a subsequent beacon frame includes data to be received by the station, if so, determining a time slice within the interval that includes the data to be received, wherein the processor maintains an association identifier list containing one unicast association identifier and an association identifier assigned when joining a multicast group, and compares a partial virtual bitmap of a beacon frame with the association identifier list, and if a bit corresponding to the association identifier list is set, then determines the time slice within the interval that includes the data to be received; and wherein the processor determines the time slice within the interval that includes the data to be received by determining from a slicing control field a number of time slices during a beacon interval and a number of bits in each slicing index field of the beacon frame, and determining from a slicing index field assigned to the station a starting point of the time slice within the interval that includes the data to be received by the station. - View Dependent Claims (16, 17, 18)
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Specification