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US-20260128771-A1 - TRAINING PPDU DESIGN FOR MILLIMETER WAVE LINKS

US20260128771A1US 20260128771 A1US20260128771 A1US 20260128771A1US-20260128771-A1

Abstract

Methods and apparatus are described for beamforming training of a millimeter wave link (mmWave link) by a wireless multi-link device (MLD). The wireless MLD determine to perform a beam establishment procedure or a beam tracking procedure for the mmWave link and generates a mmWave link training PPDU (training PPDU). The training PPDU is a Null Data Packet (NDP) and includes a PHY preamble having at least a Short Training Field (STF), a Long Training Field (LTF), and a universal Signal field (U-SIG field) carrying beam training parameters. The wireless MLD transmits the training PPDU, via the mmWave link, for reception by a second wireless MLD. In an example, all or portions of the PHY preamble correspond to an upclocked PHY preamble of a sub-7 GHz orthogonal frequency-division multiplexing (OFDM) PPDU as defined by the IEEE 802.11 standard. The training PPDU may further include training field(s) and an Integrated Millimeter Wave SIG field.

Inventors

  • XIAYU ZHENG
  • Rui Cao
  • Liwen Chu
  • Hongyuan Zhang

Assignees

  • NXP USA, INC.

Dates

Publication Date
20260507
Application Date
20251107

Claims (20)

  1. 1 . A method for beamforming training of a millimeter wave link (mmWave link) by a wireless multi-link device (MLD), comprising: determining to perform a beam establishment procedure or a beam tracking procedure for the mmWave link; generating a mmWave link training PPDU (training PPDU), wherein the training PPDU is a Null Data Packet (NDP) and includes a PHY preamble, and wherein the PHY preamble includes: a Short Training Field (STF); a Long Training Field (LTF); and a universal Signal field (U-SIG field) carrying beam training parameters; and transmitting the training PPDU, via the mmWave link, for reception by a second wireless MLD.
  2. 2 . The method of claim 1 , wherein the PHY preamble corresponds to an upclocked PHY preamble of a sub-7 GHz orthogonal frequency-division multiplexing (OFDM) PPDU as defined by the IEEE 802.11 standard.
  3. 3 . The method of claim 1 , wherein the LTF corresponds to an upclocked LTF of a sub-7 GHz orthogonal frequency-division multiplexing (OFDM) PPDU as defined by the IEEE 802.11 standard, and wherein the LTF includes a legacy or non-legacy LTF sequence design.
  4. 4 . The method of claim 1 , wherein the training PPDU further includes at least one training field (TRN field), and wherein the PHY preamble further includes a Signal field (SIG field) carrying TRN field related parameters.
  5. 5 . The method of claim 4 , wherein transmitting the training PPDU includes transmitting the PHY preamble with a first beam and transmitting at least one TRN field with a differing beam.
  6. 6 . The method of claim 4 , the at least one TRN field has the same bandwidth as an operating bandwidth for transmitting a data PPDU via the mmWave link, and wherein a different power scaling is applied to the PHY preamble and the at least one TRN field.
  7. 7 . The method of claim 4 , wherein the training PPDU is configured to train a plurality of radio frequency (RF) chains and includes a plurality of TRN fields, and wherein each TRN field includes a number of LTF symbols that is correlated to the number of RF chains.
  8. 8 . The method of claim 1 , wherein the training PPDU is generated in response to determining to perform a beam establishment procedure, further comprising: determining to perform a beam tracking procedure for the mmWave link; generating a second training PPDU, wherein the second training PPDU is a data frame and includes a PHY preamble, a data field and at least one training field (TRN field), and wherein the PHY preamble of the second training PPDU includes: a STF; a LTF; and a U-SIG field; and an Integrated Millimeter Wave SIG field (IMMW-SIG field), wherein the IMMW-SIG field and the data field carry TRN field related parameters; and transmitting the second training PPDU, via the mmWave link, for reception by the second wireless MLD.
  9. 9 . The method of claim 8 , wherein the at least one TRN field is configured in accordance with the TRN field related parameters for a transmit beam training type, a receive beam training type, or a transmit/receive beam training type, and wherein the TRN field related parameters indicate an antenna weight vector (AWV) correspondence.
  10. 10 . The method of claim 8 , wherein the bandwidth and format of a packet detection portion of the PHY preamble of the training PPDU for a beam establishment procedure or a beam tracking procedure are the same.
  11. 11 . The method of claim 1 , wherein the training PPDU is configured for the beam establishment procedure and has a smaller bandwidth than an operating bandwidth for transmitting a data PPDU via the mmWave link.
  12. 12 . The method of claim 1 , wherein the beam training parameters include one or more of a sector identifier, a beam index, a transmit radio frequency (RF) chain identifier, a training PPDU index, or a countdown index.
  13. 13 . A wireless multi-link device (MLD), comprising: one or more wireless transceivers; and one or more processors operably coupled to the one or more wireless transceivers, wherein the one or more processors are arranged to: determine to perform a beam establishment procedure or a beam tracking procedure for the mmWave link; generate a mmWave link training PPDU (training PPDU), wherein the training PPDU is a Null Data Packet (NDP) and includes a PHY and wherein the PHY preamble includes: a Short Training Field (STF); a Long Training Field (LTF); and a universal Signal field (U-SIG field) carrying beam training related parameters; and transmit the training PPDU, via the mmWave link, for reception by a second wireless MLD.
  14. 14 . The wireless MLD of claim 13 , wherein the PHY preamble corresponds to an upclocked PHY preamble of a sub-7 GHz orthogonal frequency-division multiplexing (OFDM) PPDU as defined by the IEEE 802.11 standard.
  15. 15 . The wireless MLD of claim 13 , wherein the LTF corresponds to an upclocked LTF of a sub-7 GHz orthogonal frequency-division multiplexing (OFDM) PPDU as defined by the IEEE 802.11 standard.
  16. 16 . The wireless MLD of claim 13 , wherein the training PPDU further includes at least one training field (TRN field), and wherein the PHY preamble further includes a Signal field (SIG field) carrying additional TRN field related parameters.
  17. 17 . The wireless MLD of claim 16 , wherein transmitting the training PPDU includes transmitting the PHY preamble with a first beam and transmitting at least one TRN field with a differing beam.
  18. 18 . The wireless MLD of claim 13 , wherein the training PPDU is generated in response to determining to perform a beam establishment procedure, and wherein the one or more processors are further arranged to: determine to perform a beam tracking procedure for the mmWave link; generate a second training PPDU, wherein the second training PPDU is data frame and includes a PHY preamble, a data field and at least one training field (TRN field), and wherein the PHY preamble of the second training PPDU includes: a STF; a LTF; and a U-SIG field; and an Integrated Millimeter Wave SIG field (IMMW-SIG field), wherein the IMMG-SIG field and the data field carry TRN field related parameters; and transmit the second training PPDU, via the mmWave link, for reception by the second wireless MLD.
  19. 19 . The wireless MLD of claim 13 , wherein the at least one TRN field is configured in accordance with the TRN field related parameters for a transmit beam training type, a receive beam training type, or a transmit/receive beam training type, and wherein the TRN field related parameters indicate an antenna weight vector (AWV) correspondence.
  20. 20 . A method for beamforming training of a millimeter wave link (mmWave link) by a wireless multi-link device (MLD), comprising: determining to perform a beam tracking procedure for the mmWave link; generating a mm Wave link training PPDU (training PPDU), wherein the training PPDU includes a PHY preamble and at least one training field (TRN field), and wherein the PHY preamble includes: a Short Training Field (STF); a Long Training Field (LTF); a universal Signal field (U-SIG field); and a Signal field (SIG field), wherein with the exception of the at least one training field, the format of the training PPDU corresponds to an upclocked sub-7 GHz orthogonal frequency-division multiplexing (OFDM) PPDU as defined by the IEEE 802.11 standard, and wherein one or more subfields of the U-SIG field or SIG field are redefined to carry TRN field related parameters; and transmitting the training PPDU, via the mmWave link, for reception by a second wireless MLD.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present U.S. Utility Patent application claims priority pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63/717,603, entitled “TRAINING PPDU DESIGN FOR MMWAVE LINK”, filed Nov. 7, 2024, which is hereby incorporated herein by reference in its entirety and made part of the present U.S. Utility Patent Application for all purposes. TECHNICAL FIELD This disclosure relates generally wireless communications, and more specifically to beamforming training for a millimeter wave link. BACKGROUND Wireless local area networks (WLANs) have evolved rapidly over the past couple of decades, including WLANs that conform to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards. A typical 802.11-based WLAN may be formed by one or more access points (APs) that provide a shared wireless communication medium for servicing a number of client devices or stations (STAs). In particular, an AP manages a Basic Service Set (BSS) that is identified by a Basic Service Set Identifier (BSSID) and advertised by the AP. The AP periodically broadcasts beacon frames to enable STAs within wireless range of the AP to establish and maintain communication links with the AP. More recently, the 802.11be amendment to the IEEE 802.11 standard (“Wi-Fi 7”) has added support for Multi-Link Operation (MLO). This feature increases capacity by simultaneously sending and receiving data across different frequency bands and channels (e.g., 2.4 GHz, 5 GHZ, and 6 GHZ). With MLO, for example, an access point multi-link (AP MLD) simultaneously establishes multiple links with a non-AP MLD client over more than one frequency band in order to increase throughput, reduce latency, and improve reliability. The 802.11ad amendment to the IEEE 802.11 standard (“WiGig”) further defines a standalone high-rate mmWave PHY operating in the 57-71 GHz range. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an example of a multi-link communications system in accordance with embodiments of the present disclosure; FIG. 2 illustrates an example of a frame exchange sequence of a mm Wave beam tracking procedure initiated by a non-mm Wave link in accordance with an embodiment of the present disclosure; FIG. 3 illustrates examples of legacy sub-7 GHz PPDU formats that may be redefined (in whole or part) as mmWave link training PPDUs in accordance with various embodiments of the present disclosure; FIG. 4 illustrates an example of a training field sequence for training multiple mmWave beams using a single training PPDU in accordance with embodiments of the present disclosure; FIG. 5 illustrates an example of a mmWave link Null Data Packet (NDP) in accordance with an embodiment of the present disclosure; FIG. 6 is a table illustrating an example correspondence between a number of a transmit (Tx) radio frequency (RF) chains being trained and a number of LTF symbols carried in a TRN field(s); FIG. 7 illustrates an example of an Integrated Millimeter Wave (IMMW) NDP in accordance with an embodiment of the present disclosure; FIG. 8 illustrates another example of a mm Wave NDP including a data field in accordance with an embodiment of the present disclosure; FIG. 9 illustrates an example of a training PPDU configured for beam tracking in accordance with an embodiment of the disclosure; FIG. 10 is a flow chart illustrating an example method for performing a mm Wave link beamforming training procedure (e.g., a beam establishment or beam tracking procedure) in accordance with embodiments of the present disclosure; and FIG. 11 illustrates an example of wireless multi-link device according to an embodiment of the present disclosure. DETAILED DESCRIPTION The various implementations described in the following description relate generally to “training” physical layer (PHY) protocol data units (PPDUs) to support beamforming training operations for millimeter wave (mmWave) communications. The Institute of Electrical and Electronics Engineers (IEEE) has formed an 802.11 task force to develop an integrated mm Wave (IMMW) amendment (“802.11bq”) to the 802.11 standard. The amendment is intended to meet the demands (e.g., throughput, latency, accuracy, etc.) of emergent applications such as augmented/virtual reality and proximity ranging and sensing. For example, reductions in complexity and integration cost savings may be achieved by leveraging the multi-link operation (MLO) operations defined in the sub-7 GHz band (non-mmWave link) sections of the 802.11 standard to support non-standalone operations in mm Wave links. As described with reference to FIG. 2, MLO can be utilized to support beamforming procedures such as beam establishment and beam tracking procedures. For example, MLO can be utilized to assist an initiation packet exchange, training PPDU sequence and feedback frame transmission(s). The present disclosure describes various embodiments in which all or portions of existing sub-7 GHz PPDU formats (e.