Wi-fi low energy preamble

• US 10,206,173 B2
• Filed: 05/11/2017
• Issued: 02/12/2019
• 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 Hang
• Application Number:
  US15/592,355
• Publication Number:
  US 20170245216A1
• Time in Patent Office: 642 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 device of the wireless transmission, wherein the destination information is comprised within a first signaling field of the PHY preamble, wherein the first signaling field comprises a first cyclic prefix prior to a first portion of the first signaling field and a second cyclic prefix prior to a second portion of the first signaling field, wherein the first portion of the first signaling field and the second portion of the first signaling field each comprise the destination information;

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 responsive to determining the wireless transmission is not destined to the wireless device.

2. The method of claim 1,

wherein the PHY preamble comprises an initial portion configured for channel estimation, wherein the destination information is located prior to the initial portion of the PHY preamble configured for channel estimation.

3. The method of claim 2,

wherein the destination information is 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 is 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 wireless transmission comprises sleeping or entering a lower power state for the length of the wireless transmission based on length information provided in the PHY preamble, wherein the length information indicates a length of the wireless transmission in OFDM symbols.

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, further comprising

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

8. The method of claim 7,

wherein the cyclic prefix structure of the first signaling field comprises a first single cyclic prefix prior to the first portion of the first signaling field and a second single cyclic prefix prior to the second portion of the first signaling field.

9. The method of claim 8,

wherein to identify the field of the PHY preamble, the method further comprises performing auto-correlation.

10. A wireless device, comprising:

a radio; and

processing circuitry operably coupled to the radio;

wherein the radio and the processing circuitry 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 of the wireless transmission, wherein the destination information are located within a first signaling field of the PHY preamble, wherein the first signaling field comprises a first cyclic prefix prior to a first portion of the first signaling field and a second cyclic prefix prior to a second portion of the first signaling field, wherein the first portion of the first signaling field and the second portion of the first signaling field each comprise the destination information;

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 responsive to determining the destination information indicates that the wireless transmission is not intended for the wireless device.

11. The wireless device of claim 10, wherein the destination information is differentially encoded, wherein portions of the wireless transmission subsequent to the portion configured for channel estimation are coherently encoded.

12. The wireless device of claim 10, wherein the destination information is comprised in a differentially encoded field of the PHY preamble, wherein OFDM symbols including the destination information are repeated at least twice during the differentially encoded field.

13. The wireless device of claim 10, 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 is provided subsequent to the legacy short training field and prior to the legacy long training field.

14. The wireless device of claim 13, wherein the radio and the processing circuitry 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.

15. The wireless device of claim 14, 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, the radio and the processing circuitry 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 when 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 when the auto-correlation does not result in a peak.

16. The wireless device of claim 10,

wherein dropping the remainder of the wireless transmission comprises sleeping or entering a lower power state for the length of the wireless transmission based on length information provided in the PHY preamble.

17. 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 destination device to which the wireless transmission is intended,

wherein the destination information is comprised within a first signaling field of the PHY preamble, wherein the first signaling field comprises a first cyclic prefix prior to a first portion of the first signaling field and a second cyclic prefix prior to a second portion of the first signaling field, wherein the first portion of the first signaling field and the second portion of the first signaling field each comprise the destination information, wherein the destination information is useable by a second wireless device to determine whether the signal is or is not destined to the second wireless device and to drop a remainder of the signal upon a determination that the signal is not destined to the second wireless device; and

wirelessly transmitting the signal.

18. The method of claim 17,

wherein the destination information is differentially encoded,

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

19. The method of claim 17,

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 is provided subsequent to the legacy short training field and prior to the legacy long training field.