# US 12,009,890 B2 · Codebook design for beamforming in 5G and beyond mmWave systems

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- Number: US 12,009,890 B2
- Document ID: US12009890B2
- Status: Granted
- Kind: B2
- Application number: 17/856,305
- Filed: 2022-07-01
- Published: 2023-01-26
- Granted: 2024-06-11
- Earliest claimed: 2021-07-06
- Assignees: NEC Corporation
- Applicants: NEC Laboratories America, Inc.
- Inventors: Mohammad Khojastepour; Nariman Torkzaban
- Web page: https://patentgrep.com/patent/US12009890B2

## CPC

- H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H04B 7/0482: {Adaptive codebooks}
- H04B 7/0617: {for beam forming}
- H04B: TRANSMISSION

## Abstract

A communications system for hybrid beamforming is provided. The communications system includes a base station encoding data into a plurality of streams, each transmitted through a radio frequency chain. The communication system further includes a beamforming codebook including a set of beamforming codewords. The communications system also includes a beamformer transmitting a given one of the plurality of streams through multiple antennas by adjusting a phase and a gain of symbols of the given one of the plurality of streams for each of the multiple antennas by using a corresponding beamforming coefficient of a given beamforming codeword chosen from the beamforming codebook. A beam and its corresponding beamforming codeword is designed such that the mean squared error between the beam pattern generated with the given beamforming codeword and a given beam pattern is minimized.

## Claims

### Claim 1

A communications system for hybrid beamforming,
comprising:
a base station encoding data into a plurality of streams, each transmitted through a radio frequency chain;
a beamforming codebook comprising a set of beamforming codewords; and
a beamformer transmitting a given one of the plurality of streams through multiple antennas by adjusting a phase and a gain of symbols of the given one of the plurality of streams for each of the multiple antennas by using a corresponding beamforming coefficient of a given beamforming codeword chosen from the beamforming codebook,
wherein a beam and its corresponding beamforming codeword is designed such that the mean squared error between the beam pattern generated with the given beamforming codeword and a given beam pattern is minimized, wherein the beam pattern covers a given interval in azimuth angle with a constant gain.

### Claim 2 (depends on 1)

The communications system of claim 1, wherein the beam are designed for Uniform Linear Arrays (ULA).

### Claim 3 (depends on 1)

The communications system of claim 1, wherein the beam are designed for Uniform Planar Arrays (UPA).

### Claim 4 (depends on 1)

The communications system of claim 1, wherein the beam are designed for a Twin Uniform Linear Array (TULA) antenna structure that is comprised of two Uniform Linear Arrays that are employed side by side.

### Claim 5 (depends on 4)

The communications system of claim 4, wherein a distance between the two Uniform Linear Arrays is controlled to generate an asymmetric beam pattern.

### Claim 6 (depends on 1)

The communications system of claim 1, wherein an absolute value of an mth beamforming coefficient for a beamforming codeword q is given by product of a constant factor and sinc(δq(η+m)), wherein δq and η are two constant values.

### Claim 7 (depends on 6)

The communications system of claim 6, wherein a smoothness and a sharpness of the beam is controlled by the constant value η.

### Claim 8 (depends on 4)

The communications system of claim 4, wherein an element of one ULA using the beamforming coefficient w has a corresponding element in the other ULA for which the beamforming coefficient is given by w=ejb, where b is a design constant and j is the square root of −1.

### Claim 9 (depends on 8)

The communications system of claim 8, wherein the design constant b controls an isolation between the beam and a beam counterpart, the isolation being a ratio of the average power of the beam over the average power of the beam counterpart.

### Claim 10

A method for hybrid beamforming in a communications system, comprising:
encoding, by a base station, data into a plurality of streams, each transmitted through a radio frequency chain;
a forming a beamforming codebook comprising a set of beamforming codewords; and
transmitting, by a beamformer, a given one of the plurality of streams through multiple antennas by adjusting a phase and a gain of symbols of the given one of the plurality of streams for each of the multiple antennas by using a corresponding beamforming coefficient of a given beamforming codeword chosen from the beamforming codebook,
wherein a beam and its corresponding beamforming codeword is designed such that the mean squared error between the beam pattern generated with the given beamforming codeword and a given beam pattern is minimized, wherein the beam pattern covers a given interval in azimuth angle with a constant gain.

### Claim 11 (depends on 10)

The method of claim 10, wherein the beam are designed for Uniform Linear Arrays (ULA).

### Claim 12 (depends on 10)

The method of claim 10, wherein the beam are designed for Uniform Planar Arrays (UPA).

### Claim 13 (depends on 10)

The method of claim 10, wherein the beam are designed for a Twin Uniform Linear Array (TULA) antenna structure that is comprised of two Uniform Linear Arrays that are employed side by side.

### Claim 14 (depends on 13)

The method of claim 13, wherein a distance between the two Uniform Linear Arrays is controlled to generate an asymmetric beam pattern.

### Claim 15 (depends on 10)

The method of claim 10, wherein an absolute value of an mth beamforming coefficient for a beamforming codeword q is given by product of a constant factor and sinc(δq(η+m)), wherein δq and η are two constant values.

### Claim 16 (depends on 15)

The method of claim 15, wherein a smoothness and a sharpness of the beam is controlled by the constant value η.

### Claim 17 (depends on 13)

The method of claim 13, wherein an element of one ULA using the beamforming coefficient w has a corresponding element in the other ULA for which the beamforming coefficient is given by w=ejb, where b is a design constant and j is the square root of −1.

### Claim 18 (depends on 17)

The method of claim 17, wherein the design constant b controls an isolation between the beam and a beam counterpart, the isolation being a ratio of the average power of the beam over the average power of the beam counterpart.

### Claim 19

A communications system for hybrid beamforming, comprising:
a base station encoding data into a plurality of streams, each transmitted through a radio frequency chain;
a beamforming codebook comprising a set of beamforming codewords; and
a beamformer transmitting a given one of the plurality of streams through multiple antennas by adjusting a phase and a gain of symbols of the given one of the plurality of streams for each of the multiple antennas by using a corresponding beamforming coefficient of a given beamforming codeword chosen from the beamforming codebook,
wherein a beam and its corresponding beamforming codeword is designed such that the mean squared error between the beam pattern generated with the given beamforming codeword and a given beam pattern is minimized, wherein an absolute value of an mth beamforming coefficient for a beamforming codeword q is given by product of a constant factor and sinc(δq(η+m)), wherein δq and η are two constant values.