Methods and apparatus for frame filtering in snoop-based range measurements

1. A method, comprising:

receiving, at a first communication device, a packet that includes scheduling information for a range measurement signal exchange session between a second communication device and a third communication device;

determining, at the first communication device, when the range measurement signal exchange session will occur using the scheduling information in the packet;

in response to determining when the range measurement signal exchange session will occur using the scheduling information in the packet, observing, with the first communication device, the range measurement signal exchange session, including

performing an initial analysis of range measurement packets received at the first communication device by analyzing transmitter addresses in the range measurement packets to determine whether to further process the range measurement packets for range measurement purposes, wherein the range measurement packets are packets for which the second communication device and the third communication device collectively record respective transmit times and respective receipt times; and

determining, at the first communication device, range measurements based on observing the one range measurement signal exchange session.

2. The method of claim 1 , wherein:

determining when the range measurement signal exchange session will occur using the scheduling information in the packet includes determining a time period when the range measurement signal exchange session will occur;

performing the initial analysis of range measurement packets received at the first communication device includes

determining whether transmitter addresses in range measurement packets received during the time period match an address of the second communication device,

determining to further process range measurement packets received during the time period and having transmitter addresses that match the address of the second communication device, and

determining not to further process range measurement packets received during the time period and having transmitter addresses that do not match the address of the second communication device.

3. The method of claim 2 , wherein performing the initial analysis of range measurement packets received at the first communication device received during the time period includes:

ignoring receiver addresses in range measurement packets received during the time period.

4. The method of claim 1 , wherein:

determining when the range measurement signal exchange session will occur using the scheduling information in the packet includes determining a time period when the range measurement signal exchange session will occur;

performing the initial analysis of range measurement packets received at the first communication device includes

determining whether transmitter addresses in range measurement packets received during the time period match an address of the second communication device,

determining whether receiver addresses in range measurement packets received during the time period match an address of the third communication device,

determining to further process range measurement packets received during the time period and having i) transmitter addresses that match the address of the second communication device, and ii) receiver addresses in range measurement packets that match the address of the third communication device,

determining not to further process range measurement packets received during the time period and having transmitter addresses that do not match the address of the second communication device, and

determining not to further process range measurement packets received during the time period and having receiver addresses that do not match the address of the third communication device.

5. The method of claim 4 , further comprising:

determining, at the first communication device, the address of the third communication device using the scheduling information for the range measurement signal exchange session between the second communication device and the third communication device.

6. The method of claim 5 , wherein:

the scheduling information for the range measurement signal exchange session between the second communication device and the third communication device includes a basic service set identifier (BSSID) corresponding to the third communication device; and

determining, at the first communication device, the address of the third communication device comprises determining the address of the third communication device as the BSSID included in the scheduling information.

7. An apparatus, comprising:

a network interface device associated with a first communication device, wherein the network interface device includes one or more integrated circuits (ICs) configured to

receive a packet that includes scheduling information for a range measurement signal exchange session between a second communication device and a third communication device,

determine when the range measurement signal exchange session will occur using the scheduling information in the packet, and

in response to determining when the range measurement signal exchange session will occur using the scheduling information in the packet, observe the range measurement signal exchange session, including

performing an initial analysis of range measurement packets received at the first communication device by analyzing transmitter addresses in the range measurement packets to determine whether to further process the range measurement packets for range measurement purposes, wherein the range measurement packets are packets for which the second communication device and the third communication device collectively record respective transmit times and respective receipt times; and

wherein the one or more ICs are, or a separate processor of the apparatus is, configured to determine range measurements based on observing the one range measurement signal exchange session.

8. The apparatus of claim 7 , wherein the one or more ICs are configured to:

determine a time period when the range measurement signal exchange session will occur;

perform the initial analysis of range measurement packets received at the first communication device at least by

determining whether transmitter addresses in range measurement packets received during the time period match an address of the second communication device,

determining to further process range measurement packets received during the time period and having transmitter addresses that match the address of the second communication device, and

determining not to further process range measurement packets received during the time period and having transmitter addresses that do not match the address of the second communication device.

9. The apparatus of claim 8 , wherein the one or more ICs are configured to:

ignore receiver addresses in range measurement packets received during the time period while performing the initial analysis.

10. The apparatus of claim 7 , wherein the one or more ICs are configured to:

determine a time period when the range measurement signal exchange session will occur;

perform the initial analysis of range measurement packets received at the first communication device at least by

determining whether transmitter addresses in range measurement packets received during the time period match an address of the second communication device,

determining whether receiver addresses in range measurement packets received during the time period match an address of the third communication device,

determining to further process range measurement packets received during the time period and having i) transmitter addresses that match the address of the second communication device, and ii) receiver addresses in range measurement packets that match the address of the third communication device,

determining not to further process range measurement packets received during the time period and having transmitter addresses that do not match the address of the second communication device, and

determining not to further process range measurement packets received during the time period and having receiver addresses that do not match the address of the third communication device.

11. The apparatus of claim 10 , wherein the one or more ICs are configured to:

determine the address of the third communication device using the scheduling information.

12. The apparatus of claim 11 , wherein:

the scheduling information for the range measurement signal exchange session between the second communication device and the third communication device includes a basic service set identifier (BSSID); and

the one or more ICs are configured to determine the address of the third communication device as the BSSID included in the scheduling information.

13. A non-transitory tangible computer readable medium or media, storing machine readable instructions that, when executed by one or more processors of a first communication device, cause the one or more processors to:

determine when a range measurement signal exchange session between a second communication device and a third communication device will occur using scheduling information in a packet received by the first communication device;

in response to determining when the range measurement signal exchange session will occur using the scheduling information in the packet,

perform an initial analysis of range measurement packets received at the first communication device as part of an observation, by the first communication device, of the range measurement signal exchange session, including

analyzing transmitter addresses in the range measurement packets to determine whether to further process the range measurement packets for range measurement purposes, wherein the range measurement packets are packets for which the second communication device and the third communication device collectively record respective transmit times and respective receipt times; and

determine range measurements based on observing the range measurement signal exchange session.

14. The non-transitory tangible computer readable medium or media of claim 13 , further storing machine readable instructions that, when executed by one or more processors, cause the one or more processors to:

determine a time period when the range measurement signal exchange session will occur;

perform the initial analysis of range measurement packets received at the first communication device at least by

determining whether transmitter addresses in range measurement packets received during the time period match an address of the second communication device,

determining to further process range measurement packets received during the time period and having transmitter addresses that match the address of the second communication device, and

determining not to further process range measurement packets received during the time period and having transmitter addresses that do not match the address of the second communication device.

15. The non-transitory tangible computer readable medium or media of claim 14 , further storing machine readable instructions that, when executed by one or more processors, cause the one or more processors to:

perform the initial analysis of range measurement packets received at the first communication device received during the time period at least by

ignoring receiver addresses in range measurement packets received during the time period.

16. The non-transitory tangible computer readable medium or media of claim 13 , further storing machine readable instructions that, when executed by one or more processors, cause the one or more processors to:

determine a time period when the range measurement signal exchange session will occur;

perform the initial analysis of range measurement packets received at the first communication device at least by

determining whether transmitter addresses in range measurement packets received during the time period match an address of the second communication device,

determining whether receiver addresses in range measurement packets received during the time period match an address of the third communication device,

determining to further process range measurement packets received during the time period and having i) transmitter addresses that match the address of the second communication device, and ii) receiver addresses in range measurement packets that match the address of the third communication device,

determining not to further process range measurement packets received during the time period and having transmitter addresses that do not match the address of the second communication device, and

determining not to further process range measurement packets received during the time period and having receiver addresses that do not match the address of the third communication device.

17. The non-transitory tangible computer readable medium or media of claim 16 , further storing machine readable instructions that, when executed by one or more processors, cause the one or more processors to:

determine the address of the third communication device using the scheduling information for the range measurement signal exchange session between the second communication device and the third communication device.

18. The non-transitory tangible computer readable medium or media of claim 17 , wherein:

the scheduling information for the range measurement signal exchange session between the second communication device and the third communication device includes a basic service set identifier (BSSID) corresponding to the third communication device; and

computer readable medium or media further store machine readable instructions that, when executed by one or more processors, cause the one or more processors to

determine the address of the third communication device as the BSSID included in the scheduling information.