Speculative power save

• US 8,064,411 B2
• Filed: 01/31/2007
• Issued: 11/22/2011
• Est. Priority Date: 01/31/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Ecclesine, Peter W.
• Primary Examiner(s): Karikari; Kwasi
• Application Number:
  US11/669,808
• Publication Number:
  US 20080181156A1
• Time in Patent Office: 1,756 Days
• Field of Search: 455/426.2, 455/574, 455/343.4, 455/41.2, 455/556.1, 455/503, 370/311, 370/338, 370/328, 370/318, 370/458, 713/330, 713/320
• US Class Current: 370/337
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In an example embodiment, a method for speculative power saving. The beginning portion of a header (e.g. a physical layer convergence protocol “PLCP” header of a beacon) is processed to determine whether a predefined bit is set that indicates whether the frame contains any delivery traffic indication for buffered multicast and/or unicast frames. If the bit is set, indicating the frame contains no delivery traffic indication of buffered frames, receiving and processing of the frame stops (e.g. the remainder of the PPDU is not processed) and the receiver switches to a power save state. In an example embodiment, if a predefined NULL beacon frame is detected, receiving and processing of the frame (and PPDU) stops and the receiver switches to a power save state.

Claims

1. A method, comprising:

receiving a beginning portion of a signal;

processing a header in the beginning portion of the signal;

determining whether a bit in the header is set to a predetermined logic state indicating there are no delivery traffic indications for buffered frames contained within the frame;

determining a signal quality parameter selected from a group consisting of packet error rate and bit error rate;

determining whether the signal was received correctly based on the selected signal quality parameter;

halting receiving and processing of the entire frame responsive to determining the bit is set to the predetermined logic state indicating there are no delivery traffic indications for buffered frames contained within the frame; and

switching to a power save state responsive to determining the signal was received correctly based on the selected signal quality parameter.

2. The method according to claim 1, further comprising:

the header comprises one of a group consisting of a parity bit and a checksum; and

verifying the validity of the header using the one of a group consisting of a parity bit and a checksum;

wherein the receiving and processing of less than the entire frame and switching to a power save state are responsive to determining the bit is set and the validity of the header is verified with the one of a group consisting of a parity bit and a checksum.

3. The method according to claim 1, further comprising receiving and processing a frame control field, duration field and an address field of a frame within the signal, wherein the halting of receiving and processing and the switching to a power save state are responsive to determining the bit is set, the frame control field contains data indicating the frame is a beacon frame and the address is directed to an appropriate multicast group.

4. The method according to claim 3, further comprising determining whether the frame control field contains a predefined special value.

5. The method according to claim 4, wherein the predefined special value is selected from a group consisting of 0x1110 and 0x1111.

6. The method according to claim 3, further comprising determining from the frame control fields that the frame is a beacon frame and wherein halting receiving and processing and switching to a power save state are responsive to the bit is set and determining that the frame is a beacon frame.

7. The method according to claim 6, the beacon frame comprises a traffic indication map, wherein the traffic indication map is set to zero.

8. The method according to claim 3, wherein the address field comprises a source address, a destination address, and a basic service set identifier the method further comprises verifying the source address, the destination address and the basic service set identifier.

9. A method according to claim 1 wherein the header is a physical layer convergence protocol header.

10. The method of claim 1, further comprising:

receiving a beginning portion of a second signal;

processing a header in the beginning portion of the second signal;

determining whether a bit in the header of the second signal is set to a predetermined logic state indicating there are no delivery traffic indications for buffered frames contained within the frame;

determining a second signal quality parameter selected from a group consisting of packet error rate and bit error rate for the second signal;

determining whether the second signal was received correctly based on the selected second signal quality parameter; and

continuing to process the second signal upon determining the bit in the header of the second signal is set to the predetermined logic state responsive to determining the signal was not received correctly based on the selected second signal quality parameter.

11. A method, comprising:

receiving a frame;

determining whether the frame contains a predefined null beacon frame;

determining a signal quality parameter selected from a group consisting of packet error rate and bit error rate;

determining whether the frame was received correctly based on the selected signal quality parameter; and

switching to a power save state without processing the remainder of the frame responsive to both;

i) determining the frame contains the predefined null beacon frame and ii) determining the frame was received correctly based on the signal quality parameter.

12. The method according to claim 11, wherein the predefined null beacon frame consists of a frame control field, a duration field, a source address field, a destination address field, a basic service set identifier field, and a frame check sequence field.

13. The method according to claim 12, wherein the frame control field is two octets in size, the duration field is two octets in size, the source address field is six octets in size, the destination address field is six octets in size, the basic service set identifier is six octets in size and the frame check sequence field is four octets in size.

14. The method according to claim 12, further comprising verifying the frame check sequence corresponds to the predefined null beacon frame, wherein the switching to a power save state is responsive to determining the frame contains the predetermined null beacon frame and the frame check sequence corresponds to the predefined null beacon frame.

15. An apparatus, comprising:

a wireless transceiver;

a processor coupled to the wireless transceiver and operable to process a frame received by the wireless transceiver; and

power save logic coupled to the processor;

wherein the processor is operable to process a header of the frame received by the wireless transceiver to determine whether a predefined bit in the header is set indicating there are no delivery traffic indications for buffered multicast frames contained within the frame;

wherein the processor is operable to determine a signal quality parameter selected from a group consisting of packet error rate and bit error rate;

wherein the processor is operable to determine whether the signal was received correctly based on the selected signal quality parameter; and

wherein the processor is responsive to halting receiving and processing of the frame and to signal the power save logic to switch to a power save state responsive to determining the predefined bit is set, to signal the power save logic to switch to a power save, and the signal was received correctly based on the selected signal quality parameter.

16. The apparatus according to claim 15, further comprising:

the header comprises one of a group consisting of a parity bit and a checksum; and

wherein the processor is configured to verifying the validity of the header using the one of a group consisting of a parity bit and a checksum; and

wherein the processor is responsive to halting receiving and processing of the frame and to signal the power save logic to switch to a power save state responsive to determining the predefined bit is set and the validity of the header is verified with the one of a group consisting of a parity bit and a checksum.

17. The apparatus according to claim 15, further comprising

the processor is configured to process a frame control field, duration field and an address field within the frame;

and

wherein the processor is responsive to halting receiving and processing the frame and to signal the power save logic to switch to a power save state responsive to determining the predefined bit is set, the frame control field contains data indicating the frame is a beacon frame and the address is directed to an appropriate multicast group.

18. An apparatus, comprising:

a wireless transceiver;

a processor coupled to the wireless transceiver and operable to process a frame received by the wireless transceiver; and

power save logic coupled to the processor;

wherein the processor is operable to process the frame to determine whether the frame contains a predefined null beacon frame;

wherein the processor is operable to determine a signal quality parameter selected from a group consisting of packet error rate and bit error rate;

wherein the processor is operable to determine whether the signal was received correctly based on the selected signal quality parameter; and

wherein the processor is operable to signal the power save logic to switch to a power save state and halt processing the remainder of the frame responsive to;

i) the determining the frame contains the predefined null beacon frame and ii) the determining the signal was received correctly based on the signal quality parameter.

19. The apparatus according to claim 18, wherein the null beacon frame comprises a frame control sequence, further comprising the processor is operable to verify the frame control sequence corresponds to the predefined null beacon frame, wherein the switching to a power save state is responsive to determining the frame contains the predetermined null beacon frame and the frame control sequence corresponds to the predefined null beacon frame.