Mirrored split passive scanning

Patent metadata

Field	Value
Publication number	US-12445944-B2
Application number	US-202118043006-A
Country	US
Kind code	B2
Filing date	Feb 23, 2021
Priority date	Oct 14, 2020
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

This disclosure provides methods, devices, and systems for performing passive scanning operations on one or more wireless channels. In some implementations, a wireless communication device configures an off-channel scan time and a passive scanning period for passive scanning operations based on latency requirements of a low-latency application, and selects a home channel dwell time for the passive scanning operations. The wireless communication device may perform the passive scanning operation by alternating between listening for beacon frames on one or more second wireless channels for the configured off-channel scan time and dwelling on a home channel for the selected home channel dwell time during a first portion of the configured scanning period. The wireless communication device also may listen for beacon frames on the one or more second wireless channels during a second portion of the configured scanning period that is defined by the selected home channel dwell time.

First claim

What is claimed is:

1. A method of wireless communication performed by an apparatus of a wireless communication device, comprising:
configuring an off-channel scan time for one or more passive scanning operations to be less than or equal to a maximum off-channel scan duration permitted by a first wireless access point (AP) operating on a first wireless channel;
selecting a home channel dwell time for the one or more passive scanning operations;
configuring a scanning period of the one or more passive scanning operations to be less than or equal to a maximum scanning period permitted by the first wireless AP; and
performing the one or more passive scanning operations on one or more corresponding second wireless channels, each of the one or more passive scanning operations comprising:
alternating between:
listening for beacon frames on a respective second wireless channel for the configured off-channel scan time;
dwelling on the first wireless channel for the selected home channel dwell time during a first portion of the configured scanning period; and
listening for beacon frames on the respective second wireless channel during a second portion of the configured scanning period, the second portion spanning a period of time defined by the selected home channel dwell time.

2. The method of claim 1 , wherein the alternating between comprises:
passively scanning the respective second wireless channel during a first time period defined by the configured off-channel scan time;
dwelling on the first wireless channel during a second time period defined by the selected home channel dwell time;
passively scanning the respective second wireless channel during a third time period defined by the configured off-channel scan time; and
dwelling on the first wireless channel during a fourth time period defined by the selected home channel dwell time.

3. The method of claim 2 , wherein the listening for beacon frames on the respective second wireless channel during the second portion of the configured scanning period comprises:
passively scanning the respective second wireless channel during a fifth time period defined by the selected home channel dwell time.

4. The method of claim 3 , wherein the fifth time period is configured to begin one beacon interval after a beginning of the second time period.

5. The method of claim 3 , further comprising:
receiving a transmission of a first group of beacon frames over the respective second wireless channel during the first time period;
missing a transmission of a second group of beacon frames over the respective second wireless channel during the second time period;
receiving a transmission of a third group of beacon frames over the respective second wireless channel during the third time period; and
receiving a subsequent transmission of the second group of beacon frames over the respective second wireless channel during the fifth time period.

6. The method of claim 5 , further comprising:
initializing a timer to a value indicative of a beacon interval of a second AP operating on the respective second wireless channel;
initiating a countdown of the timer at a beginning of the second time period; and
passively scanning the respective second wireless channel at a beginning of the fifth time period based on the timer reaching a zero value.

7. The method of claim 6 , wherein the fifth time period is configured for receiving one or more beacon frames over the respective second wireless channel that were missed by the wireless communication device while dwelling on the first wireless channel during the second time period.

8. A method of wireless communication performed by an apparatus of a wireless communication device, comprising:
selecting a home channel dwell time for one or more passive scanning operations;
configuring an off-channel scan time for a first passive scanning operation to be less than or equal to a maximum off-channel scan duration permitted by a first wireless access point (AP) operating on a first wireless channel;
performing one or more first passive scanning operations on one or more corresponding second wireless channels, each of the one or more first passive scanning operations including:
alternating between:
listening for beacon frames on a respective second wireless channel for the configured off-channel scan time; and
dwelling on the first wireless channel for the selected home channel dwell time; and

performing a second passive scanning operation on each respective second wireless channel, the second passive scanning operation including:
dwelling on the first wireless channel for the configured off-channel scan time; and
listening for beacon frames on the respective second wireless channel for the selected home channel dwell time.

9. The method of claim 8 , further comprising:
discovering one or more second APs operating on a corresponding second wireless channel during a respective first passive scanning operation; and
determining an AP coverage level on the corresponding second wireless channel provided by the one or more discovered second APs before performing the second passive scanning operation.

10. The method of claim 9 , wherein determining the AP coverage level comprises:
reporting the one or more discovered second APs from a medium access control (MAC) layer of the wireless communication device to an application layer of the wireless communication device before performing the second passive scanning operation.

11. A wireless communication device, comprising:
at least one memory; and
at least one processor communicatively coupled with the at least one memory, the at least one processor operable to cause the wireless communication device to:
configure an off-channel scan time for one or more passive scanning operations to be less than or equal to a maximum off-channel scan duration permitted by a first wireless access point (AP) operating on a first wireless channel;
select a home channel dwell time for the one or more passive scanning operations;
configure a scanning period of the one or more passive scanning operations to be less than or equal to a maximum scanning period permitted by the first wireless AP; and
perform the one or more passive scanning operations on one or more corresponding second wireless channels, wherein, to perform each of the one or more passive scanning operations, the at least one processor is operable to cause the wireless communication device to alternate between:
listening for beacon frames on a respective second wireless channel for the configured off-channel scan time;
dwelling on the first wireless channel for the selected home channel dwell time during a first portion of the configured scanning period; and
listening for beacon frames on the respective second wireless channel during a second portion of the configured scanning period, the second portion spanning a period of time defined by the selected home channel dwell time.

12. The wireless communication device of claim 11 , wherein the maximum off-channel scan duration and the maximum scanning period are specified by an off-channel scanning procedure associated with the first wireless AP.

13. The wireless communication device of claim 11 , wherein the first wireless channel comprises a home channel associated with an active real-time application specifying one or more low-latency requirements.

14. The wireless communication device of claim 11 , wherein the one or more second wireless channels comprise 16 dynamic frequency selection (DFS) channels in a 5 GHz frequency spectrum.

15. The wireless communication device of

Assignees

• Qualcomm Inc

Inventors

• Homchaudhuri Sandip
• Raissinia Alireza
• Del Prado Pavon Javier
• Dai Shuibing
• Li Zhao
• Phogat Vikram
• Basaralu Subramanya Prasanna

Classifications

• H04W48/12

  using downlink control channel · CPC title

• H04W88/02

  Terminal devices · CPC title

• H04W84/12

  WLAN [Wireless Local Area Networks] · CPC title

• H04W74/0866

  using a dedicated channel for access · CPC title

• H04W8/005

  Discovery of network devices, e.g. terminals · CPC title