# US 11,444,666 B2 · Channel condition estimation

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- Number: US 11,444,666 B2
- Document ID: US11444666B2
- Status: Granted
- Kind: B2
- Application number: 16/931,555
- Filed: 2020-07-17
- Published: 2021-03-11
- Granted: 2022-09-13
- Earliest claimed: 2020-07-17
- Assignees: Telefonaktiebolaget LM Ericsson (publ)
- Applicants: Telefonaktiebolaget LM Ericsson (publ)
- Inventors: Sven Petersson; Fredrik Athley; Mikael Coldrey; Andreas Nilsson
- Web page: https://patentgrep.com/patent/US11444666B2

## CPC

- H04B 7/0469: {taking special antenna structures, e.g. cross polarized antennas into account}
- H04B 7/0617: {for beam forming}
- H04L 25/0204: {of multiple channels}
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

There is provided mechanisms for obtaining channel conditions per antenna element, A method is performed by a wireless radio transceiver device comprising N antenna elements in an antenna array with analog beamforming and being configured to communicate using beams. The method comprises obtaining, for a stationary radio propagation channel, channel conditions for signals received by the wireless radio transceiver device in M beams, where M>1. The method comprises transforming the channel conditions for the M beams to channel conditions for the N antenna elements by using a relation based on beamforming weights that map the N antenna elements to the M beams.

## Claims

### Claim 1

A method for obtaining channel conditions per antenna element, the method being performed by a stationary access node comprising N antenna elements in an antenna array with analog beamforming and being configured to communicate via a stationary radio propagation channel utilizing beams, wherein N>1, the method comprising:
obtaining, for the stationary radio propagation channel, channel conditions for signals received by the stationary access node in M beams, where M>1, wherein the channel conditions comprise M channel estimates; and
transforming the M channel estimates for the M beams to N channel estimates for the N antenna elements by utilizing a relation based on beamforming weights that map the N antenna elements to the M beams, wherein
the N channel estimates are channel estimates of the stationary radio propagation channel.

### Claim 2

A stationary access node for obtaining channel conditions per antenna element, the stationary access node comprising:
N antenna elements in an antenna array with analog beamforming, wherein N>1; and
processing circuitry being configured to cause the stationary access node to:
communicate via a stationary radio propagation channel utilizing beams;
obtain, for the stationary radio propagation channel, channel conditions for signals received by the stationary access node in M beams, where M>1, wherein the channel conditions comprise M channel estimates; and
transform the M channel estimates for the M beams to N channel estimates for the N antenna elements by utilizing a relation based on beamforming weights that map the N antenna elements to the M beams, wherein
the N channel estimates are channel estimates of the stationary radio propagation channel.

### Claim 3 (depends on 2)

The stationary access node of claim 2, wherein the stationary access node is one of: an access node or a user equipment (UE).

### Claim 4 (depends on 2)

The stationary access node of claim 2, wherein the stationary access node is configured to communicate with another stationary access node via the stationary radio propagation channel.

### Claim 5 (depends on 2)

The stationary access node of claim 2, wherein MN.

### Claim 6 (depends on 2)

The stationary access node of claim 2, wherein M=N, and wherein the M beams are mutually orthogonal with respect to each other.

### Claim 7 (depends on 2)

The stationary access node of claim 2, wherein M<N, and wherein the relation specifies correlations between the N antenna elements.

### Claim 8 (depends on 2)

The stationary access node of claim 2, wherein the beamforming weights are precoder weights.

### Claim 9 (depends on 8)

The stationary access node of claim 8, wherein the relation is defined by a pseudo-inverse of the precoder weights.

### Claim 10 (depends on 2)

The stationary access node of claim 2, wherein the relation is defined by a zero-forcing estimator of the channel estimates for the N antenna elements.

### Claim 11 (depends on 2)

The stationary access node of claim 2, wherein the relation is defined by a linear minimum mean square error estimator of the channel estimates for the N antenna elements.

### Claim 12 (depends on 2)

The stationary access node of claim 2, wherein
each of the N antenna elements has its own phase shifter,
the beamforming weights determine settings for the phase shifters, and
the processing circuitry is further configured to cause the stationary access node to determine updated settings for the phase shifters based on the N channel estimates for the N antenna elements.

### Claim 13 (depends on 2)

The stationary access node of claim 2, wherein
each of the N antenna elements has its own amplitude taper,
the beamforming weights determine settings for the amplitude tapers, and
the processing circuitry being configured to further cause the stationary access node to
determine updated settings for the amplitude tapers based on the N channel estimates for the N antenna elements.

### Claim 14 (depends on 2)

The stationary access node of claim 2, wherein the channel estimates for the N antenna elements are indicative of at least one of signal to interference plus noise ratio (SINR) of the received signals, and channel throughput of the stationary radio propagation channel.

### Claim 15 (depends on 2)

The stationary access node of claim 2, wherein the stationary access node is served by another stationary access node, and wherein the channel estimates for M beams are indicative of the signals as received from the another stationary access node as well as interfering signals received from at least yet another access node.

### Claim 16 (depends on 2)

The stationary access node of claim 2, wherein obtaining the channel estimates for the M beams further comprises:
sweeping through the M beams, and
while sweeping through the M beams, receiving the signals in the M beams.

### Claim 17 (depends on 2)

The stationary access node of claim 2, wherein the channel estimates for the M beams are representative of channel estimations for the M beams as averaged over multiple time and/or frequency samples.

### Claim 18

A wireless device comprising a radio transceiver device for obtaining channel estimates per antenna element, the radio transceiver device comprising:
N antenna elements in an antenna array and being configured to communicate utilizing beams, wherein N>1; and
processing circuitry being configured to cause the radio transceiver device to:
obtain for a radio propagation channel, channel conditions for signals received by the radio transceiver device in M beams, where M>1, wherein the channel conditions comprise M channel estimates; and
transform the M channel estimates for the M beams to N channel estimates for the N antenna elements, wherein
the N channel estimates are channel estimates of the radio propagation channel.

### Claim 19 (depends on 18)

The wireless device of claim 18, the wireless device is configured to transform the M channel estimates utilizing a relation based on beamforming weights that map the N antenna elements to the M beams.