# US 2020/0403680 A1 · Channel stae information for multiple access points

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- Number: US 2020/0403680 A1
- Document ID: US20200403680A1
- Status: Published application
- Kind: A1
- Application number: 17/012,796
- Filed: 2020-09-04
- Published: 2020-12-24
- Earliest claimed: 2019-10-30
- Assignees: Intel Corporation
- Inventors: Qinghua Li; Feng Jiang; Xiaogang Chen; Po-Kai Huang; Jonathan Segev; Dibakar Das
- Web page: https://patentgrep.com/patent/US20200403680A1

## CPC

- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/024: Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
- H04B 7/0452: Multi-user MIMO systems
- H04B 7/0617: {for beam forming}
- H04B 7/0628: {Diversity capabilities}
- H04B 7/0632: {Channel quality parameters, e.g. channel quality indicator [CQI]}
- H04W 48/12: using downlink control channel
- H04W 84/12: WLAN [Wireless Local Area Networks]
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Methods, apparatuses, and computer readable media for channel state information for multiple access points are disclosed. Channel station information (CSI) may be coordinated for multiple access points (APs) where one AP may act as a master AP with other AP acting as slave APs. The channel station information may be based on information from null data packets received by stations from multiple-APs, which may enable a multi-AP coordinated beamforming (CBF) to be determined based on the received first CSI reports. New frame formats are disclosed that include fields for including APs. Overlapping basic service set (OBSS) stations may respond to APs that are not within their BSS. Some embodiments relate to passive range finding in a multi-AP sounding where location configuration information (LCI) changes for one of the APs.

## Claims

### Claim 1

An apparatus of a master access point (AP), the apparatus comprising memory; and processing circuitry coupled to the memory, the processing circuitry configured to:
encode a null data packet announcement (NDPA) frame, the NDPA frame comprising an identification of the master AP, an indication that a slave AP is to transmit a second NDP simultaneously with the master AP transmitting a first NDP, and an indication that a station is to provide a channel state information (CSI) report to the master station;
configure the master AP to transmit the NDPA frame;
encode for transmission the first NDP;
encode for transmission a beam forming report poll (BFRP) trigger frame, the BFRP trigger frame indicating a resource unit (RU) allocation for the station to transmit the CSI report to the master station; and
decode the CSI report in accordance with the RU allocation.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the BFRP trigger frame is a first BFRP trigger frame, the CSI report is a first CSI report, and the station is a first station, and wherein the processing circuitry is further configured to:
encode for transmission a poll frame, the poll frame to indicate to the slave AP to transmit a second BFRP trigger frame to solicit a second CSI report from a second station.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the poll frame is a first poll frame, and wherein the processing circuitry is further configured to:
in response to not receiving the second BRIT trigger frame, encode for transmission a second poll frame, the second poll frame to indicate to the slave AP to transmit a third BFRP trigger frame to solicit the second CSI report from the second station.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the RU is a first RU, the CSI reports is a first CSI report, and the station is a first station, and wherein the NDPA frame further comprises an indication that a second station is to provide a second CSI report to the master station, wherein the BFRP trigger frame further indicates a second RU allocation for the second station to simultaneously transmit the second CSI report to the master station, and wherein decode the first CSI report comprises decode the first CSI report and the second CSI report.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein the BFRP trigger frame is a first BFRP trigger frame and wherein the first BFRP trigger frame indicates that the slave AP is to transmit a second BFRP trigger frame an interframe duration after the first station has transmitted the first CSI. reports and the second station has transmitted the second CSI report.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein the BFRP trigger frame is a first BFRP trigger frame, the CSI report is a first CSI report, and the station is a first station, and wherein the first BFRP trigger frame indicates to the slave AP to transmit a second BFRP trigger frame to solicit a second CSI report from a second station after the first station transmits the first CSI report.

### Claim 7 (depends on 2)

The apparatus of claim 2, wherein the first CSI report is based on the first NDP and the second NDP.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein the NDPA frame comprises an indication of a resource allocation for the slave AP to transmit the second NDP.

### Claim 9 (depends on 8)

The apparatus of claim 8, wherein the resource allocation comprises one of an 80 MHz subchannel or a 20 MHz subchannel, and wherein the slave AP is to transmit the second NDP a short interframe space (SIFS) after receiving the NDPA frame.

### Claim 10 (depends on 2)

The apparatus of claim 2, wherein the first station is an overlapping basic service set (OBSS) station.

### Claim 11 (depends on 2)

The apparatus of claim 2, wherein the indication that the slave AP is to transmit the NDP simultaneously with the master AP comprises an identification of the slave AP.

### Claim 12 (depends on 2)

The apparatus of claim 2 wherein the processing circuitry is further configured to:
receive from the slave AP the second CSI report via a backhaul connection.

### Claim 13 (depends on 2)

The apparatus of claim 2, wherein the processing circuitry is further configured to:
determining a multi-AP coordinated beamforming (CBF) based on the received first CSI report.

### Claim 14 (depends on 1)

The apparatus of claim 1, wherein the NDPA frame further comprises an indication that a plurality of stations are to provide CSI reports to the master station and the indication that the plurality of stations are to provide CSI reports to the master station comprises the indication that the station is to provide the CSI report to the master station, wherein the BFRP trigger frame comprises an indication of RU allocations for the plurality of stations to simultaneously transmit the CSI reports to the master station and wherein the plurality of stations comprises the station, and wherein decode the CSI report further comprises decode the CSI reports in accordance with the RU allocations, the RU allocations comprising the RU allocation.

### Claim 15

The apparatus of claim I further comprising: mixer circuitry to downconvert RF signals to baseband signals; and synthesizer circuitry, the synthesizer circuitry comprising one of a fractional-N synthesizer or a fractional N/N+1 synthesizer, the synthesizer circuitry configured to generate an output frequency for use by the mixer circuitry, wherein the processing circuitry is configured to decode the baseband signals, the baseband signals including the R2I NDP frame.

### Claim 16 (depends on 1)

The apparatus of claim 1 further comprising: mixer circuitry to down-convert RF signals to baseband signals; and synthesizer circuitry, the synthesizer circuitry comprising a delta-sigma synthesizer, the synthesizer circuitry configured to generate an output frequency for use by the mixer circuitry, wherein the processing circuitry is configured to decode the baseband signals, the baseband signals including the R2I NDP frame.

### Claim 17

A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of an apparatus of a station (STA), the instructions to configure the one or more processors to:
encode a trigger frame for null data packet announcement (NDPA) frames, the trigger frame comprising an identification of the master AP, an indication that a slave AP is to transmit a second NDPA frame simultaneously with the master AP transmitting a first NDPA frame, and that the slave AP is to transmit a second null data packet (NDP) simultaneously with a master station transmitting a first NDP;
configure the master station to transmit the trigger frame;
encode the first NDPA frame, the first NDPA frame comprising an identification of the master AP and an indication that a plurality of stations are to provide channel state information (CSI) reports to the master station;
configure the master AP to transmit the first NDPA. frame;
encode a first NDP for transmission;
encode for transmission a beam forming report poll (BFRP) trigger frame, the first BFRP trigger frame indicating resource units (RUs) for the plurality of stations to simultaneously transmit the CSI reports to the master station; and
decode the CSI reports in accordance with the RUs.

### Claim 18 (depends on 17)

The non-transitory computer-readable storage medium of claim 17, wherein the CSI reports are based on the first NDP and the second NDP.

### Claim 19

An apparatus of a station, the apparatus comprising memory; and processing circuitry coupled to the memory, the processing circuitry configured to:
decode a null data packet announcement (NDPA) frame, the NDPA frame comprising an identification of the master AP, an indication that a slave AP is to transmit a second NDP simultaneously with the master AP transmitting a first NDP, and an indication that the station is to provide a channel state information (CSI) report to the master station;
decode a first NDP and the second NDP;
determine the CSI report based on the first NDP and the second NDP;
decode a beam forming report poll (BFRP) trigger frame, the BFRP trigger frame indicating a resource unit (RU) for the station to transmit the CSI report to the master station; and
configure the station to transmit the CSI report to the master station in accordance with the resource unit.

### Claim 20 (depends on 19)

The apparatus of claim 19, wherein the master station is an overlapping basic service set (OBSS) AP.