# US 11,310,743 B2 · Determining a tone sequence for wake-up procedures

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- Number: US 11,310,743 B2
- Document ID: US11310743B2
- Status: Granted
- Kind: B2
- Application number: 16/924,567
- Filed: 2020-07-09
- Published: 2021-01-14
- Granted: 2022-04-19
- Earliest claimed: 2019-07-12
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Geert Arnout Awater; Stephen Jay Shellhammer; Didier Johannes Richard Van Nee; Bin Tian
- Web page: https://patentgrep.com/patent/US11310743B2

## CPC

- H04L 27/2613: {Structure of the reference signals}
- H04W 52/0235: {where the received signal is a power saving command}
- H04L 1/0003: {by switching between different modulation schemes}
- H04L 1/0013: {Rate matching, e.g. puncturing or repetition of code symbols}
- H04L 1/0021: {in which the algorithm uses adaptive thresholds}
- H04L 1/0033: {arrangements specific to the transmitter}
- H04L 27/2614: {Peak power aspects}
- H04W 52/0222: {in packet switched networks}
- H04L 1/0016: {involving special memory structures, e.g. look-up tables}
- Y02D 30/70: in wireless communication networks
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

This disclosure provides systems, methods, and apparatuses, including computer programs encoded on computer storage media, for determining one or more tone sequences (for example, for wake-up procedures). In one aspect, an access point (AP) may wake a mobile station (STA) from a low power mode using a wake-up packet, where an ON symbol of the wake-up packet is modulated using a tone sequence. To reduce the likelihood of a STA falsely identifying the ON symbol as a packet preamble, the AP may implement a tone sequence that satisfies a correlation metric threshold. For example, for a set of candidate tone sequences, each tone sequence may be associated with a correlation metric and peak-to-average-power ratio (PAPR) coordinate pair, and the tone sequence for modulating the ON symbol of the wake-up packet may be selected from a lower convex hull of the coordinate pairs.

## Claims

### Claim 1

An apparatus of an access point (AP) for wireless communications, comprising:
a processing system configured to:
determine that a station (STA) associated with the AP is to be awakened from a low power mode; and
generate a wake-up packet for reception by a wake-up radio of the STA to trigger wake-up of the STA, the wake-up packet including a tone sequence for an ON symbol of the wake-up packet, wherein the tone sequence is associated with a maximum correlation metric that is less than a maximum correlation metric threshold; and
an interface configured to:
output the wake-up packet for transmission to the STA.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein:
each of a plurality of cyclic shifts of the ON symbol satisfy the maximum correlation metric threshold.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein:
the maximum correlation metric is based at least in part on a maximum value of a plurality of absolute values of normalized auto-correlations over one or more sample start times of the tone sequence, one or more repetition numbers of the tone sequence, or a combination thereof.

### Claim 4 (depends on 3)

The apparatus of claim 3, wherein:
the normalized auto-correlations correspond to repetition intervals over a length of time equal to a short training sequence duration within the ON symbol using the tone sequence.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein:
the tone sequence further comprises a maximum peak-to-average-power ratio that satisfies a maximum peak-to-average-power ratio threshold by being less than the maximum peak-to-average-power ratio threshold.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein:
satisfaction of the maximum peak-to-average-power ratio threshold is based at least in part on each of a plurality of cyclic shifts of the ON symbol satisfying the maximum peak-to-average-power ratio threshold.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein:
the tone sequence comprises a binary phase shift keying modulated tone sequence, a quadrature phase shift keying modulated tone sequence, a quadrature amplitude modulated tone sequence, or a combination thereof.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein:
the processing system is further configured to:
select a data rate for the ON symbol of the wake-up packet; and
determine the tone sequence based at least in part on the data rate.

### Claim 9 (depends on 8)

The apparatus of claim 8, wherein:
the data rate comprises a high data rate and the ON symbol spans a first time period and uses a first number of subcarriers; or
the data rate comprises a low data rate and the ON symbol spans a second time period longer than the first time period and uses a second number of subcarriers greater than the first number of subcarriers.

### Claim 10 (depends on 1)

The apparatus of claim 1, wherein:
the tone sequence comprises one of the following sequences:
[1 −1 1 1 −1 −1 0 −1 1 1 −1 −1 −1], [−1 1 1 −1 −1 1 0 1 −1 −1 −1 −1 −1], [1 −1 1 1 −1 1 0 1 1 1 −1 −1 −1], [1 −1 1 −1 −1 −1 0 −1 1 −1 −1 −1 −1], [−1 1 −1 1 1 −1 0 1 1 −1 −1 −1 −1], or [−1 1 1 1 −1 1 0 −1 −1 −1 1 −1 −1].

### Claim 11

An apparatus for selection of a tone sequence, comprising:
a memory; and
a processing system configured to:
identify a plurality of candidate tone sequences;
store, in the memory and in association with an identifier for corresponding candidate tone sequences, a correlation metric and a peak-to-average-power ratio for each of the plurality of candidate tone sequences;
associate the correlation metric and the peak-to-average-power ratio for each of the plurality of candidate tone sequences into a plurality of coordinate pairs, each pair representative of one of the plurality of candidate tone sequences;
identify one or more of the plurality of coordinate pairs that define a lower convex hull of the plurality of coordinate pairs; and
select the tone sequence for an ON symbol of a wake-up packet from the one or more coordinate pairs that define the lower convex hull.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein:
the processing system configured to identify the one or more of the plurality of coordinate pairs that define the lower convex hull of the plurality of coordinate pairs is further configured to:
identify a first coordinate pair of the plurality of coordinate pairs having a smallest correlation metric;
identify a second coordinate pair of the plurality of coordinate pairs having a steepest negative slope with respect to the first coordinate pair; and
identify additional coordinate pairs of the plurality of coordinate pairs, each of the additional coordinate pairs having a correlation metric that is greater than that of a most recently identified coordinate pair and having a steepest negative slope with respect to the most recently identified coordinate pair,
wherein the first coordinate pair, the second coordinate pair, and the additional coordinate pairs comprise the one or more of the plurality of coordinate pairs that define the lower convex hull of the plurality of coordinate pairs.

### Claim 13 (depends on 12)

The apparatus of claim 12, wherein:
the processing system is further configured to:
sort the plurality of coordinate pairs based on the peak-to-average-power ratio prior to identifying the first coordinate pair.

### Claim 14 (depends on 11)

The apparatus of claim 11, wherein:
the processing system configured to identify the one or more of the plurality of coordinate pairs that define the lower convex hull of the plurality of coordinate pairs is further configured to:
represent the plurality of coordinate pairs in a scatter plot with a first axis representing the correlation metric and a second axis representing a peak-to-average-power ratio grid; and
identify the one or more of the plurality of coordinate pairs from the lower convex hull of the scatter plot.

### Claim 15 (depends on 11)

The apparatus of claim 11, wherein:
the correlation metric for each candidate tone sequence of the plurality of candidate tone sequences comprises a maximum correlation metric for each candidate tone sequence; and
the peak-to-average-power ratio for each candidate tone sequence of the plurality of candidate tone sequences comprises a maximum peak-to-average-power ratio for each candidate tone sequence.

### Claim 16

A method for wireless communications at an apparatus of an access point (AP), comprising:
determining that a station (STA) associated with the AP is to be awakened from a low power mode;
generating a wake-up packet for reception by a wake-up radio of the STA to trigger wake-up of the STA, the wake-up packet including a tone sequence for an ON symbol of the wake-up packet, wherein the tone sequence is associated with a maximum correlation metric that is less than a maximum correlation metric threshold; and
transmitting the wake-up packet to the STA.

### Claim 17 (depends on 16)

The method of claim 16, wherein:
each of a plurality of cyclic shifts of the ON symbol satisfy the maximum correlation metric threshold.

### Claim 18 (depends on 16)

The method of claim 16, wherein:
the maximum correlation metric is based at least in part on a maximum value of a plurality of absolute values of normalized auto-correlations over one or more sample start times of the tone sequence, one or more repetition numbers of the tone sequence, or a combination thereof.

### Claim 19 (depends on 16)

The method of claim 16, wherein:
the tone sequence comprises one of the following sequences:
[1 −1 1 1 −1 −1 0 −1 1 1 −1 −1 −1], [−1 1 1 −1 −1 1 0 1 −1 −1 −1 −1 −1], [1 −1 1 1 −1 1 0 1 1 1 −1 −1 −1], [1 −1 1 −1 −1 −1 0 −1 1 −1 −1 −1 −1], [−1 1 −1 1 1 −1 0 1 1 −1 −1 −1 −1], or [−1 1 1 1 −1 1 0 −1 −1 −1 1 −1 −1].

### Claim 20 (depends on 18)

The method of claim 18, wherein:
the normalized auto-correlations correspond to repetition intervals over a length of time equal to a short training sequence duration within the ON symbol using the tone sequence.

### Claim 21 (depends on 16)

The method of claim 16, wherein:
the tone sequence further comprises a maximum peak-to-average-power ratio that satisfies a maximum peak-to-average-power ratio threshold by being less than the maximum peak-to-average-power ratio threshold.

### Claim 22 (depends on 21)

The method of claim 21, wherein:
satisfaction of the maximum peak-to-average-power ratio threshold is based at least in part on each of a plurality of cyclic shifts of the ON symbol satisfying the maximum peak-to-average-power ratio threshold.

### Claim 23 (depends on 16)

The method of claim 16, wherein:
the tone sequence comprises a binary phase shift keying modulated tone sequence, a quadrature phase shift keying modulated tone sequence, a quadrature amplitude modulated tone sequence, or a combination thereof.

### Claim 24 (depends on 16)

The method of claim 16, further comprising:
selecting a data rate for the ON symbol of the wake-up packet; and
determining the tone sequence based at least in part on the data rate.

### Claim 25 (depends on 24)

The method of claim 24, wherein:
the data rate comprises a high data rate and the ON symbol spans a first time period and uses a first number of subcarriers; or
the data rate comprises a low data rate and the ON symbol spans a second time period longer than the first time period and uses a second number of subcarriers greater than the first number of subcarriers.

### Claim 26

A method for selection of a tone sequence, comprising:
identifying a plurality of candidate tone sequences;
storing, in memory and in association with an identifier for corresponding candidate tone sequences, a correlation metric and a peak-to-average-power ratio for each of the plurality of candidate tone sequences;
associating the correlation metric and the peak-to-average-power ratio for each of the plurality of candidate tone sequences into a plurality of coordinate pairs, each pair representative of one of the plurality of candidate tone sequences;
identifying one or more of the plurality of coordinate pairs that define a lower convex hull of the plurality of coordinate pairs; and
selecting the tone sequence for an ON symbol of a wake-up packet from the one or more coordinate pairs that define the lower convex hull.

### Claim 27 (depends on 26)

The method of claim 26, wherein:
identifying the one or more of the plurality of coordinate pairs that define the lower convex hull of the plurality of coordinate pairs comprises:
identifying a first coordinate pair of the plurality of coordinate pairs having a smallest correlation metric;
identifying a second coordinate pair of the plurality of coordinate pairs having a steepest negative slope with respect to the first coordinate pair; and
identifying additional coordinate pairs of the plurality of coordinate pairs, each of the additional coordinate pairs having a correlation metric that is greater than that of a most recently identified coordinate pair and having a steepest negative slope with respect to the most recently identified coordinate pair,
wherein the first coordinate pair, the second coordinate pair, and the additional coordinate pairs comprise the one or more of the plurality of coordinate pairs that define the lower convex hull of the plurality of coordinate pairs.

### Claim 28 (depends on 27)

The method of claim 27, further comprising:
sorting the plurality of coordinate pairs based on the peak-to-average-power ratio prior to identifying the first coordinate pair.

### Claim 29 (depends on 26)

The method of claim 26, wherein:
identifying the one or more of the plurality of coordinate pairs that define the lower convex hull of the plurality of coordinate pairs comprises:
representing the plurality of coordinate pairs in a scatter plot with a first axis representing the correlation metric and a second axis representing a peak-to-average-power ratio grid; and
identifying the one or more of the plurality of coordinate pairs from the lower convex hull of the scatter plot.

### Claim 30 (depends on 26)

The method of claim 26, wherein:
the correlation metric for each candidate tone sequence of the plurality of candidate tone sequences comprises a maximum correlation metric for each candidate tone sequence; and
the peak-to-average-power ratio for each candidate tone sequence of the plurality of candidate tone sequences comprises a maximum peak-to-average-power ratio for each candidate tone sequence.