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US-20260129629-A1 - DYNAMIC BANDWIDTH EXPANSION ACTIVATION AND TERMINATION OPERATION

US20260129629A1US 20260129629 A1US20260129629 A1US 20260129629A1US-20260129629-A1

Abstract

Signal mechanisms are described for performing dynamic bandwidth expansion (DBE) at an access point (AP). In one embodiment, the AP and stations (STAs) exchange signals indicating their respective DBE capabilities (e.g., whether DBE is supported, maximum dynamic BW, etc.). Later, the AP (or a network controller) can determine to perform DBE. For example, the load on the AP may jump because the AP is located in a conference room or an event center. To provide additional BW, the AP (or RRM) can determine to perform DBE to increase the bandwidth available to the AP. To do so, the AP transmits a DBE announcement to inform the STAs. This announcement can include information such as bandwidth, center frequency, whether a subchannel is punctured, etc.). The AP and STAs can then use the expanded bandwidth.

Inventors

  • Binita Gupta
  • Malcolm M. Smith
  • Brian D. Hart

Assignees

  • CISCO TECHNOLOGY, INC.

Dates

Publication Date
20260507
Application Date
20251219

Claims (20)

  1. 1 . A method comprising managing, by an access point, a basic service set (BSS) on a first operating channel and at a first channel bandwidth; determining a mode switch time for a Dynamic Bandwidth Expansion (DBE) mode of operation for the BSS; prior to the mode switch time, transmitting by the access point, a wireless management frame that announces a switch to the DBE mode of operation for the BSS, the management frame including data indicating the mode switch time and one or more DBE parameters; at the mode switch time, expanding, by the access point, a channel bandwidth of the BSS to a second channel bandwidth greater than the first channel bandwidth; and implementing, by the access point, the BSS in the DBE mode of operation at up to the second channel bandwidth for all DBE supporting stations.
  2. 2 . The method of claim 1 wherein the one or more DBE parameters comprises at least one of a center channel frequency and an expanded DBE channel bandwidth.
  3. 3 . The method of claim 1 wherein the one or more DBE parameters comprises one or more punctured subchannels.
  4. 4 . The method of claim 1 wherein the data indicating the mode switch time is a number of target beacon transmission times until the mode switch time.
  5. 5 . The method of claim 1 further comprising transmitting, after the mode switch time, one or more additional management frames including data indicating the DBE mode of operation as active and the one or more DBE parameters.
  6. 6 . The method of claim 1 further comprising: advertising within the BSS, by the access point, support for the DBE mode of operation.
  7. 7 . The method of claim 1 wherein the wireless management frame is a beacon frame, a probe response frame or a (re)association response frame.
  8. 8 . The method of claim 1 wherein the wireless management frame comprises a critical update flag set to a value indicating a critical update.
  9. 9 . The method of claim 8 further comprising: incrementing a BSS Parameters Change Count, wherein the management frame further comprises the incremented BSS parameters change count.
  10. 10 . An access point comprising: one or more memories; and one or more processors communicatively coupled to the one or more memories, wherein the one or more processors are configured to, individually or collectively, perform operations comprising: managing, by the access point, a basic service set (BSS) on a first operating channel and at a first channel bandwidth; accessing a determination of a mode switch time for a Dynamic Bandwidth Expansion (DBE) mode of operation for the BSS; prior to the mode switch time, transmitting by the access point, a wireless management frame that announces a switch to the DBE mode of operation for the BSS, the management frame including data indicating the mode switch time and one or more DBE parameters; at the mode switch time, expanding, by the access point, a channel bandwidth of the BSS to a second channel bandwidth greater than the first channel bandwidth; and implementing, by the access point, the BSS in the DBE mode of operation at up to the second channel bandwidth for all DBE supporting stations.
  11. 11 . The access point of claim 10 wherein the one or more DBE parameters comprises at least one of a center channel frequency and an expanded DBE channel bandwidth.
  12. 12 . The access point of claim 10 wherein the one or more DBE parameters comprises one or more punctured subchannels.
  13. 13 . The access point of claim 10 , wherein the data indicating the mode switch time is a number of target beacon transmission times until the mode switch time.
  14. 14 . The access point of claim 10 , the operations further comprising: transmitting, after the mode switch time, one or more additional management frames including data indicating the DBE mode of operation as active and the one or more DBE parameters.
  15. 15 . The access point of claim 10 , the operations further comprising: advertising within the BSS, by the access point, support for the DBE mode of operation.
  16. 16 . The access point of claim 10 wherein the wireless management frame is a beacon frame, a probe response frame or a (re)association response frame.
  17. 17 . The access point of claim 10 wherein the wireless management frame comprises a critical update flag set to a value indicating a critical update.
  18. 18 . The access point of claim 17 , the operations further comprising: incrementing a BSS Parameters Change Count, wherein the management frame further comprises the incremented BSS parameters change count.
  19. 19 . A non-transitory computer readable storage medium comprising instructions that when executed configure one or more processors of an access point (AP) to perform operations comprising: managing, by the access point, a basic service set (BSS) on a first operating channel and at a first channel bandwidth; accessing a determination of a mode switch time for a Dynamic Bandwidth Expansion (DBE) mode of operation for the BSS; prior to the mode switch time, transmitting by the access point, a wireless management frame that announces a switch to the DBE mode of operation for the BSS, the management frame including data indicating the mode switch time and one or more DBE parameters; at the mode switch time, expanding, by the access point, a channel bandwidth of the BSS to a second channel bandwidth greater than the first channel bandwidth; and implementing, by the access point, the BSS in the DBE mode of operation at up to the second channel bandwidth for all DBE supporting stations.
  20. 20 . The non-transitory computer readable storage medium of claim 19 wherein the one or more DBE parameters comprises at least one of a center channel frequency, an expanded DBE channel bandwidth or one or more punctured subchannels.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of co-pending U.S. patent application Ser. No. 19/205,972 filed May 12, 2025, which claims benefit of co-pending U.S. provisional patent application Ser. No. 63/766,935 filed Mar. 4, 2025 and U.S. provisional patent application Ser. No. 63/645,639 filed May 10, 2024. The aforementioned related patent applications are herein incorporated by reference in their entirety. TECHNICAL FIELD Embodiments presented in this disclosure generally relate to real-time dynamic bandwidth (BW) expansion (RT-DBE) or simply DBE. BACKGROUND In enterprise deployments, wider channel bandwidths (e.g. 80, 160 & 320 MHz) are unlikely to be deployed, because the RRM (Radio Resource Management) logic and policy for enterprise deployments prefer stability for the WLAN and hence employs frequency reuse where available spectrum bandwidth is split among neighboring APs for those APs to operate on non-overlapping channels (each with different primacy channel). RRM logic typically employs high frequency reuse (e.g., a 10+ frequency reuse pattern), leading to adoption of e.g. 20/40 MHz channel bandwidth for 5 GHz and 20/40/80 MHz for 6 GHz. High client density also discourages use of wide-channels because Enhanced Distributed Channel Access (EDCA) performance quickly degrades in HD (e.g. 100+ stations (STAs)). RRM also limits channel changes and bandwidth changes due to legacy compatibility issues observed in 2.4 and 5 GHz spectrum where some legacy STAs will roam away from the AP when a channel switch is announced or may not connect to an AP that supports channel changes/channel switch. Hence, to avoid these negative impacts of legacy devices, channel changes are typically done infrequently in enterprise WLAN networks—e.g., once every day during off-peak hours or once every 8-12 hours, to minimize legacy compatibility concerns. Load on an AP typically varies with some APs experiencing high load on a temporal basis, e.g., during a meeting the access point(s) (AP(s)) in the conference room experience higher load because more devices are connected versus APs outside in the cubicle areas where smaller number of devices are connected. Given the increased load is temporary, but channel and bandwidth assignment are for much longer time scales (e.g. for a day), current enterprise deployments miss on the opportunity to provide higher throughput to serve higher temporal load. Channel Switch Announcement (CSA) or Extended CSA (E-CSA) in 802.11 standard can support changing the operating BW of a basic service set (BSS). However, as described above using existing CSA or E-CSA to obtain more frequency or perform dynamic bandwidth change for RT-DBE has undesirable impacts on legacy devices. For example, most legacy stations (STAs) respond to CSA/E-CSA by roaming away and then roaming back (causing double scan/roam hit). To perform RT BW expansion using CSA/E-CSA (e.g., every few seconds or minutes), the double roaming has a serious negative impact on the performance of the legacy STAs. In addition, some legacy STAs will not associate with an AP that supports CSA. Further, CSA/E-CSA BW changes is designed for use with radio resource management (RRM), which is primarily for non-real time (or longer time scale) changes to channel and BW selection, and is not expected to be used for fast/real-time/frequent BW changes (e.g., at each transmit opportunity (TXOP) level, every millisecond, every second, or every minute or every few minutes etc.). In addition, the CSA/ECSA is mainly used for changing primary channel, which is not the case for DBE (or RT-DBE), where primary 20 MHz channel remains same and only BW changes. Using CSA/ECSA for only bandwidth change may cause field interop issues with legacy devices. BRIEF DESCRIPTION OF THE DRAWINGS So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate typical embodiments and are therefore not to be considered limiting, other equally effective embodiments are contemplated. FIG. 1 is timing graph for performing DBE, according to one embodiment. FIG. 2 is a flowchart for performing DBE, according to one embodiment. FIG. 3 is a scheme for signaling DBE capabilities between an AP and a STA, according to one embodiment. FIG. 4 is a scheme for announcing a DBE, according to one embodiment. FIGS. 5A and 5B are schemes for signaling DBE BW parameters, according to one embodiment. FIG. 6 is a scheme for signaling DBE BW parameters, according to one embodiment. FIG. 7 is a flowchart for adjusting the BW of a neighboring AP in response to a DBE, according to one embodiment. FIG. 8 depicts an example computing device configured to perform various aspects of the present