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US-12628185-B2 - Preemption scheduling for raw deterministic traffic

US12628185B2US 12628185 B2US12628185 B2US 12628185B2US-12628185-B2

Abstract

Techniques for managing communications between access points (APs) and stations (STAs) are described herein. In one embodiment, an AP broadcasts a trigger message to a plurality of STAs, the trigger message including a matrix defining a plurality of resource units (RUs) that the plurality of STAs are assigned to transmit or receive data, and a fragment flag. The presence of the fragment flag, within the scheduling matrix, informs the AP that the data transmission that the fragment flag is appended to is a partial transmission that will be completed in a subsequent transmission opportunity.

Inventors

  • Pascal Thubert
  • Jerome Henry
  • Juan Carlos Zuniga
  • Matthew A. Silverman
  • Domenico Ficara
  • Amine Choukir
  • Robert E. BARTON

Assignees

  • CISCO TECHNOLOGY, INC.

Dates

Publication Date
20260512
Application Date
20230329

Claims (20)

  1. 1 . An access point (AP) comprising: a transmitter configured to: transmit a first message to a station (STA) indicating a first fixed duration in a first resource unit (RU) that the STA can use to transmit data to the AP; receive, after transmitting the first message to the STA, traffic in the first RU from the STA having a fragment flag, the fragment flag indicating the STA sent an incomplete packet during the first fixed duration, wherein the fragment flag is transmitted at an end of the first RU; and transmit a second message to the STA indicating a second fixed duration in a second RU that the STA can use to transmit a remaining portion of the packet to the AP.
  2. 2 . The AP of claim 1 , wherein the first and second RUs are a same frequency band.
  3. 3 . The AP of claim 1 , wherein the first and second RUs are different frequency bands.
  4. 4 . The AP of claim 1 , wherein the first RU comprises the first fixed duration for the STA and a third fixed duration for a second STA to use to transmit data to the AP.
  5. 5 . The AP of claim 1 , wherein the transmitter is configured to: before receiving the fragment flag, receive a preemption flag from the STA indicating the STA is switching between transmitting different priority traffic within the first fixed duration of the first RU.
  6. 6 . The AP of claim 5 , wherein the traffic is prioritized based on classification of the data as one of express, non-express, or deterministic.
  7. 7 . The AP of claim 6 , wherein the first message comprises a trigger frame scheduling transmission of data for a first transmission opportunity of the first fixed duration and the second message comprises an echo trigger frame scheduling transmission of data for a second transmission opportunity of the second fixed duration that is shorter than the first fixed duration.
  8. 8 . A method of data transmission, executed by an AP comprising: transmitting a first message to a station (STA) indicating a first fixed duration in a first resource unit (RU) that the STA can use to transmit data to the AP; receiving, after transmitting the first message to the STA, traffic in the first RU from the STA having a fragment flag, the fragment flag indicating the STA sent an incomplete packet during the first fixed duration, wherein the fragment flag is transmitted at an end of the first RU; and transmitting a second message to the STA indicating a second fixed duration in a second RU that the STA can use to transmit a remaining portion of the packet to the AP.
  9. 9 . The method of claim 8 , wherein the first and second RUs are a same frequency band.
  10. 10 . The method of claim 8 , wherein the first and second RUs are different frequency bands.
  11. 11 . The method of claim 8 , wherein the first RU comprises the first fixed duration for the STA and a third fixed duration for a second STA to use to transmit data to the AP.
  12. 12 . The method of claim 8 , further comprising, before receiving the fragment flag: receiving a preemption flag from the STA indicating the STA is switching between transmitting different priority traffic within the first fixed duration of the first RU.
  13. 13 . The method of claim 12 , wherein the traffic is prioritized based on classification of the data as one of express, non-express, or deterministic.
  14. 14 . The method of claim 13 , wherein the first message comprises a trigger frame scheduling transmission of data for a first transmission opportunity of the first fixed duration and the second message comprises an echo trigger frame scheduling transmission of data for a second transmission opportunity of the second fixed duration that is shorter than the first fixed duration.
  15. 15 . A non-transitory computer-readable medium containing computer program code that, when executed by operation of one or more computer processors, performs an operation comprising: transmitting a first message to a station (STA) indicating a first fixed duration in a first resource unit (RU) that the STA can use to transmit data to an AP; receiving, after transmitting the first message to the STA, traffic in the first RU from the STA having a fragment flag, the fragment flag indicating the STA sent an incomplete packet during the first fixed duration, wherein the fragment flag is transmitted at an end of the first RU; and transmitting a second message to the STA indicating a second fixed duration in a second RU that the STA can use to transmit a remaining portion of the packet to the AP.
  16. 16 . The non-transitory computer-readable medium of claim 15 , wherein the first and second RUs are a same frequency band.
  17. 17 . The non-transitory computer-readable medium of claim 15 , wherein the first and second RUs are different frequency bands.
  18. 18 . The non-transitory computer-readable medium of claim 17 , wherein the first RU comprises the first fixed duration for the STA and a third fixed duration for a second STA to use to transmit data to the AP.
  19. 19 . The non-transitory computer-readable medium of claim 18 , wherein the operation further comprises, before receiving the fragment flag: receiving a preemption flag from the STA indicating the STA is switching between transmitting different priority traffic within the first fixed duration of the first RU.
  20. 20 . The non-transitory computer-readable medium of claim 19 , wherein the first message comprises a trigger frame scheduling transmission of data for a first transmission opportunity of the first fixed duration and the second message comprises an echo trigger frame scheduling transmission of data for a second transmission opportunity of the second fixed duration that is shorter than the first fixed duration.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims benefit of U.S. provisional patent application Ser. No. 63/367,978 filed Jul. 8, 2022. The aforementioned related patent application is herein incorporated by reference in its entirety. TECHNICAL FIELD Embodiments presented in this disclosure generally relate to techniques for managing Wi-Fi communications between access points and stations. BACKGROUND Time-Sensitive Networking (TSN) extends Wi-Fi communications with deterministic elements and time-sensitive capabilities. However, a short coming of TSN networking is handling partial data transmission with interrupts and pre-emption schemes. The embodiments described herein set forth a fragment flag that improves transmission interruption and pre-emption. TSN enables reliable and timely communication over networks by providing a suite of mechanisms and protocols that enable networked devices to exchange critical data with very low latency and high reliability. Some of the key features of TSN include: time synchronization, traffic scheduling, bandwidth reservation, and stream identification. One important aspect of TSN is Frame Replication and Elimination for Multipoint Applications (FREMA) preemption. FREMA preemption is a mechanism that enables a higher-priority stream to preempt a lower-priority stream during transmission in order to meet strict timing requirements. However, for Wi-Fi communications between Access Points (AP) and Stations (STAs), TSN and deterministic communications may benefit from improvements in data transmission interruption and pre-emption. The implementation of TSN, in the context of Wi-Fi networks, relies on effective communication between APs and STAs. APs are devices that schedule the transmission of data to and from STA. STAs are devices that use data sent over the Wi-Fi network to carry out specific tasks. Some examples of STAs include personal computers, cellular phones, and servers. Because Wi-Fi transmission are not bound to cables or wires, each STA is unaware of transmission by other STAs and each STA tends to be unaware of the busy/idle state of the APs. Wi-Fi STA transmit a data frame and wait for an acknowledgement from the intended receiver that the data frame was received. If no acknowledgement is received, the STA can send the transmission again. The STA will repeatedly send transmission until an acknowledgement is received. There is a cost to repeatedly transmitting frames. Each retransmission attempt results in longer wait times between retransmissions that compound, creating greater and greater overhead costs. Another cost associated with the transmission of data over Wi-Fi networks is the efficient allocation of data frames to available RUs. If the data that could be transmitted is larger than an available time slot for assigned to an RU, then the data is not scheduled for transmission and the transmission opportunity is wasted. A similar cost is associated with data that is smaller than the time slot assigned to an RU. If the data is smaller than the size of the time slot assigned to an RU, then padding is inserted into the transmission to fill out the size of the time slot. The insertion of padding consumes resources that could be more efficiently allocated. 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 illustrates a non-deterministic downlink transmission. FIG. 2 illustrates a non-deterministic uplink transmission. FIG. 3 illustrates a deterministic data communication with a fragment flag according to an embodiment of the current disclosure. FIG. 4 illustrates a wireless network according to an embodiment of the current disclosure. FIG. 5 illustrates a communication network according to an embodiment of the current disclosure. FIG. 6 illustrates a method according to an embodiment of the current disclosure. To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially used in other embodiments without specific recitation. DESCRIPTION OF EXAMPLE EMBODIMENTS Overview One embodiment presented in this disclosure includes an AP including a transmitter configured to transmit a first message to a STA indicating a fixed duration in a first RU that the STA can use to transmit data to the AP. After transmitting the message to the STA, the AP receives traffic in the first RU from the STA having a fragment flag, the fragment flag indi