# US 12,003,441 B2 · Backward compatible physical layer convergence procedure (PLCP) protocol data unit (PPDU) design in wireless local area network (WLAN) system

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- Number: US 12,003,441 B2
- Document ID: US12003441B2
- Status: Granted
- Kind: B2
- Application number: 17/626,543
- Filed: 2020-07-10
- Published: 2022-08-11
- Granted: 2024-06-04
- Earliest claimed: 2019-07-12
- Assignees: InterDigital Patent Holdings, Inc.
- Applicants: Interdigital Patent Holdings, Inc.
- Inventors: Hanqing Lou; Li-Hsiang Sun; Rui Yang; Joseph S. Levy; Xiaofei Wang
- Web page: https://patentgrep.com/patent/US12003441B2

## CPC

- H04L 5/0044: {Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH}
- H04L 5/0046: {Determination of the number of bits transmitted on different sub-channels}
- H04L 1/0026: {Transmission of channel quality indication}
- H04L 5/0037: {Inter-user or inter-terminal allocation}
- H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)}
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04L 5/006: {Quality of the received signal, e.g. BER, SNR, water filling}
- H04L 5/0085: {when channel conditions change}
- H04L 5/0091: {Signalling for the administration of the divided path, e.g. signalling of configuration information}
- H04L 25/0224: {using sounding signals}
- H04L 25/03146: {with a recursive structure (H04L25/03127 takes precedence)}
- H04L 25/067: {providing soft decisions, i.e. decisions together with an estimate of reliability (H04L25/068 and H04L25/069 take precedence; sequence estimation techniques H04L25/03178)}
- H04L 27/2613: {Structure of the reference signals}
- H04L 27/2646: {using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length}
- H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports}
- H04L 5/0026: {Division using four or more dimensions, e.g. beam steering or quasi-co-location [QCL]}
- H04L 5/0035: {Resource allocation in a cooperative multipoint environment}
- H04L 27/2035: {using a single or unspecified number of carriers}
- 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)

## Abstract

Methods and apparatuses are described herein for feedback based midamble adaptation. For example, a first station (STA) may transmit, to a second STA, a request frame that includes an indicator indicating a request for midamble information. The first STA may receive, from the second STA, a response frame that includes the midamble information determined by the second STA based on one or more channel measurements associated with the second STA. The midamble information may include a midamble report, a Doppler measurement report, or the like. The midamble report or the Doppler measurement report may include at least one of a midamble periodicity, a mobility/Doppler level, or the like. Based on the midamble information, the first STA may generate a physical layer convergence procedure (PLCP) protocol data unit (PPDU) that includes at least one midamble within a data portion of the PPDU.

## Claims

### Claim 1

A method for use in a first station (STA), the method comprising:
transmitting, to a second STA, a request frame that includes an indicator indicating a request for midamble information;
receiving, from the second STA, a response frame that includes the midamble information indicating one or more channel conditions based on the request frame; and
transmitting a physical layer convergence procedure (PLCP) protocol data unit (PPDU) that includes at least one midamble generated based on the midamble information.

### Claim 2 (depends on 1)

The method of claim 1, wherein the midamble information includes a midamble report or a Doppler measurement report.

### Claim 3 (depends on 2)

The method of claim 2, wherein the midamble report or the Doppler measurement report includes at least one of a midamble periodicity, a mobility/Doppler level, a midamble frequency, a category for a midamble setting, a number of midamble required, or an indicator indicating whether the first STA needs to use a midamble.

### Claim 4 (depends on 3)

The method of claim 3, wherein the midamble periodicity indicates zero periodicity, low periodicity, medium periodicity, or high periodicity of the at least one midamble located within a data portion of the PPDU, and wherein the low periodicity indicates the midamble periodicity to be higher relative to the zero periodicity and lower relative to medium periodicity, the medium periodicity indicates the midamble periodicity to be higher relative to the low periodicity and lower relative to high periodicity, and the high periodicity indicates the midamble periodicity to be higher relative to the to medium periodicity.

### Claim 5 (depends on 4)

The method of claim 4, wherein the zero periodicity of the at least one midamble indicates that there is no need to use a midamble.

### Claim 6 (depends on 4)

The method of claim 4, wherein the low periodicity, the medium periodicity, or the high periodicity of the at least one midamble indicates a periodicity being associated with a number of OFDMA symbols based on the at least one midamble located within the data portion of the PPDU.

### Claim 7 (depends on 4)

The method of claim 4, wherein the mobility/Doppler level indicates a low mobility/Doppler level, a medium mobility/Doppler level, or a high mobility/Doppler level.

### Claim 8 (depends on 1)

The method of claim 1, wherein the at least one midamble is within a data portion of the PPDU, and wherein the at least one midamble includes channel estimation information.

### Claim 9

A first station (STA) comprising:
a receiver; and
a transmitter,
the transmitter configured to transmit, to a second STA, a request frame that includes an indicator indicating a request for midamble information;
the receiver configured to receive, from the second STA, a response frame that includes the midamble information indicating one or more channel conditions based on the request frame; and
the transmitter configured to transmit a physical layer convergence procedure (PLCP) protocol data unit (PPDU) that includes at least one midamble generated based on the midamble information.

### Claim 10 (depends on 9)

The first STA of claim 9, wherein the midamble information includes a midamble report or a Doppler measurement report.

### Claim 11 (depends on 10)

The first STA of claim 10, wherein the midamble report or the Doppler measurement report includes at least one of a midamble periodicity, a mobility/Doppler level, a midamble frequency, a category for a midamble setting, a number of midamble required, or an indicator indicating whether the first STA needs to use a midamble.

### Claim 12 (depends on 11)

The first STA of claim 11, wherein the midamble periodicity indicates zero periodicity, low periodicity, medium periodicity, or high periodicity of the at least one midamble located within a data portion of the PPDU, and wherein the low periodicity indicates the midamble periodicity to be higher relative to the zero periodicity and lower relative to medium periodicity, the medium periodicity indicates the midamble periodicity to be higher relative to the low periodicity and lower relative to high periodicity, and the high periodicity indicates the midamble periodicity to be higher relative to the to medium periodicity.

### Claim 13 (depends on 12)

The first STA of claim 12, wherein the zero periodicity of the at least one midamble indicates that there is no need to use a midamble.

### Claim 14 (depends on 12)

The first STA of claim 12, wherein the low periodicity, the medium periodicity, or the high periodicity of the at least one midamble indicates a periodicity being associated with a number of OFDMA symbols based on the at least one midamble located within the data portion of the PPDU.

### Claim 15 (depends on 12)

The first STA of claim 12, wherein the mobility/Doppler level indicates a low mobility/Doppler level, a medium mobility/Doppler level, or a high mobility/Doppler level.

### Claim 16 (depends on 9)

The first STA of claim 9, wherein the at least one midamble is within a data portion of the PPDU, and wherein the at least one midamble includes channel estimation information.