Wi-Fi Low Energy Preamble

• US 20150257106A1
• Filed: 02/20/2015
• Published: 09/10/2015
• Est. Priority Date: 03/06/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Mujtaba, Syed Aon, Kim, Joonsuk
• Granted Patent: US 9,681,386 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04W 28/0221 power availability or consumption
• CPC Class Codes: H04W 52/0238 where the received signal is an unwanted signal, e.g. interference or idle signal
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

This disclosure relates to low energy communication techniques. According to some embodiments, a wireless transmission may be received by a wireless device. The wireless transmission may include a physical layer (PHY) preamble and PHY data. The PHY preamble may include destination information indicating a destination and length information indicating a length (or duration) of the wireless transmission. The destination and length information may be included prior to a portion of the PHY preamble configured for channel estimation. The wireless device may determine whether the wireless transmission is destined to the wireless device based on the destination information. If the wireless transmission is not destined to the wireless device, the wireless device may drop a remainder of the wireless transmission.

Claims

1. A method, comprising:

by a wireless device;

receiving a wireless transmission, wherein the wireless transmission comprises a physical layer (PHY) preamble and PHY data, wherein the PHY preamble comprises destination information indicating a destination and length information indicating a length of the wireless transmission;

determining whether the wireless transmission is or is not destined to the wireless device based on the destination information; and

dropping a remainder of the wireless transmission if the wireless transmission is not destined to the wireless device.

2. The method of claim 1,

wherein the PHY preamble comprises a portion configured for channel estimation, wherein the destination information and the length information are located prior to the portion of the PHY preamble configured for channel estimation.

3. The method of claim 2,

wherein the destination information and the length information are differentially encoded;

wherein portions of the wireless transmission subsequent to the portion configured for channel estimation are coherently encoded.

4. The method of claim 1,

wherein the wireless transmission is an IEEE 802.11 wireless communication, wherein the PHY preamble comprises at least a legacy short training field and a legacy long training field, wherein the destination information and the length information are provided subsequent to the legacy short training field and prior to the legacy long training field.

5. The method of claim 1,

wherein dropping the remainder of the first wireless transmission comprises sleeping or entering a low power state for the length of the first wireless transmission based on the length information.

6. The method of claim 1,

wherein the destination information comprises one of a partial media access control (MAC) address of the destination device or a partial association ID (PAID) of the destination device.

7. The method of claim 1,

wherein the length information indicates a length of the wireless transmission in one or bytes or OFDM symbols.

8. The method of claim 1, further comprising

identifying a field of the PHY preamble comprising the destination information and the length information as a LE-SIG field based at least in part on a cyclic prefix structure of the LE-SIG field.

9. A wireless device, comprising:

a radio; and

an processing element operably coupled to radio;

wherein the radio and the processing element are configured to;

receive a wireless transmission,

wherein the wireless transmission comprises a physical layer (PHY) preamble and PHY data,

wherein the PHY preamble comprises destination information indicating a destination and length information indicating a length of the wireless transmission,

wherein the PHY preamble comprises a portion configured for channel estimation,

wherein the destination information and the length information are located prior to the portion of the PHY preamble configured for channel estimation;

determine whether or not the wireless transmission is intended for the wireless device based on the destination information; and

drop a remainder of the wireless transmission if the destination information indicates that the wireless transmission is intended for the wireless device.

10. The wireless device of claim 9,

wherein the destination information and the length information are differentially encoded,

wherein portions of the wireless transmission subsequent to the portion configured for channel estimation are coherently encoded.

11. The wireless device of claim 9,

wherein the destination information and the length information are comprised in a differentially encoded field of the PHY preamble, wherein OFDM symbols the destination information and the length information are repeated at least twice during the differentially encoded field.

12. The wireless device of claim 9,

wherein the wireless transmission is an IEEE 802.11 wireless communication, wherein the PHY preamble comprises at least a legacy short training field and a legacy long training field, wherein the destination information and the length information are provided subsequent to the legacy short training field and prior to the legacy long training field.

13. The wireless device of claim 12, wherein the radio and the processing element are further configured to:

determine whether a field of the PHY preamble subsequent to the legacy short training field is a legacy long training field or a low energy signaling field comprising the destination information and the length information.

14. The wireless device of claim 13, wherein to determine whether the field of the PHY preamble subsequent to the legacy short training field is a legacy long training field or a low energy signaling field, the radio and the processing element are further configured to:

collect samples for a first 0.8 μ

s of the field subsequent to the legacy short training field;

perform auto-correlation of the first 0.8 μ

s with a next 0.8 μ

s of the field subsequent to the legacy short training field;

determine that the field subsequent to the legacy short training field is a legacy long training field if the auto-correlation results in a peak; and

determine that the field subsequent to the legacy short training field is a low energy signaling field if the auto-correlation does not result in a peak.

15. The wireless device of claim 9,

wherein dropping the remainder of the first wireless transmission comprises sleeping or entering a low power state for the length of the first wireless transmission based on the length information.

16. A method, comprising:

by a first wireless device;

generating a signal for wireless transmission,

wherein the signal comprises a physical layer (PHY) preamble and PHY data,

wherein the PHY preamble comprises destination information indicating a device to which the wireless transmission is intended and length information indicating a length of the wireless transmission,

wherein the PHY preamble comprises a portion configured for channel estimation,

wherein the destination information and the length information are located prior to the portion of the PHY preamble configured for channel estimation; and

wirelessly transmitting the signal.

17. The method of claim 16,

wherein the destination information and the length information are differentially encoded,

wherein portions of the signal subsequent to the portion configured for channel estimation are coherently encoded.

18. The method of claim 16,

wherein the destination information comprises a partial association ID (PAID) of the destination device.

19. The method of claim 16,

wherein the signal is an IEEE 802.11 wireless communication signal, wherein the PHY preamble comprises at least a legacy short training field and a legacy long training field, wherein the destination information and the length information are provided subsequent to the legacy short training field and prior to the legacy long training field.

20. The method of claim 16,

wherein the destination and length information are comprised in a low energy signaling (LE-SIG) field.