Wi-Fi low energy preamble

• US 9,681,386 B2
• Filed: 02/20/2015
• Issued: 06/13/2017
• Est. Priority Date: 03/06/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Mujtaba, Syed Aon, Kim, Joonsuk
• Primary Examiner(s): Yeung, Mang
• Application Number:
  US14/626,947
• Publication Number:
  US 20150257106A1
• Time in Patent Office: 844 Days
• Field of Search: 370311
• 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, wherein the PHY preamble comprises an initial portion configured for channel estimation, wherein the destination information and the length information are located prior to the initial portion of the PHY preamble configured for channel estimation or are included in the initial portion of the PHY preamble configured for channel estimation;

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

in response to determining that the wireless transmission is not destined to the wireless device, dropping a remaining portion of the wireless transmission if the wireless transmission is not destined to the wireless device.

2. The method of claim 1, wherein the destination information and the length information are located prior to the initial 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 one or more portions of the wireless transmission subsequent to the initial portion configured for channel estimation are coherently encoded.

4. The method of claim 1,

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

6. The method of claim 1, further comprising

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

7. The method of claim 1, wherein the PHY preamble comprises a first legacy training field and a second legacy training field, and wherein the destination information and the length information are provided subsequent to the first legacy training field and prior to the second legacy training field.

8. A wireless device, comprising:

a radio; and

an processing element operably coupled to the 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 an initial portion configured for channel estimation, wherein the destination information and the length information are located prior to or within the initial 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 not intended for the wireless device.

9. The wireless device of claim 8,

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

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

10. The wireless device of claim 8,

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

11. The wireless device of claim 8,

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.

12. The wireless device of claim 11, 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 signaling field comprising the destination information and the length information.

13. The wireless device of claim 12, 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 signaling field comprising the destination information and the length information, 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 signaling field comprising the destination information and the length information if the auto-correlation does not result in a peak.

14. The wireless device of claim 8, wherein the PHY preamble comprises a first legacy training field and a second legacy training field, and wherein the destination information and the length information are provided subsequent to the first legacy training field and prior to the second legacy training field.

15. An apparatus, comprising:

one or more memory elements; and

one or more processing elements communicatively coupled to the one or more memory elements, wherein the one or more processing elements are configured to operate with the one or more memory elements 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 an initial portion configured for channel estimation, wherein the destination information and the length information are located prior to the initial portion of the PHY preamble configured for channel estimation or are included in the initial portion of the PHY preamble configured for channel estimation;

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

in response to determining that the wireless transmission is not destined to the wireless device, drop a remaining portion of the wireless transmission if the wireless transmission is not destined to the wireless device.

16. The apparatus of claim 15, wherein the destination information and the length information are located prior to the initial portion of the PHY preamble configured for channel estimation.

17. The apparatus of claim 16,

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

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

18. The apparatus of claim 15,

wherein the wireless transmission comprises 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.

19. The apparatus of claim 15, wherein the one or more processing elements are further configured to:

identify a field of the PHY preamble comprising the destination information and the length information based at least in part on a cyclic prefix structure of the field.

20. The apparatus of claim 15, wherein the PHY preamble comprises a first legacy training field and a second legacy training field, and wherein the destination information and the length information are provided subsequent to the first legacy training field and prior to the second legacy training field.