# US 2018/0026367 A1 · Beam Forming Using an Antenna Arrangement

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- Number: US 2018/0026367 A1
- Document ID: US20180026367A1
- Status: Published application
- Kind: A1
- Application number: 15/548,445
- Filed: 2015-03-06
- Published: 2018-01-25
- Earliest claimed: 2015-03-06
- Assignees: Telefonaktiebolaget LM Ericsson (publ)
- Applicants: Telefonaktiebolaget LM Ericsson (publ)
- Inventors: Fredrik Athley; Sven Petersson
- Web page: https://patentgrep.com/patent/US20180026367A1

## CPC

- H01Q 3/40: with phasing matrix
- H01Q 1/246: {specially adapted for base stations}
- H01Q 21/0025: {Modular arrays}
- H04B 7/0617: {for beam forming}
- H04B 7/0691: {using subgroups of transmit antennas}
- H04B 7/10: Polarisation diversity; Directional diversity
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)
- H04B: TRANSMISSION

## Abstract

There is provided mechanisms for beam forming using an antenna array comprising dual polarized elements. A method comprises generating one or two beam ports, wherein the one or two beam ports are defined by combining at least two non-overlapping subarrays. Each subarray has two subarray ports, the two subarray ports having identical power patterns and mutually orthogonal polarization. The at least two non-overlapping subarrays are combined via expansion weights. The expansion weights map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays. At least some of the expansion weights have identical non-zero magnitude and are related in phase to form a transmission lobe. The method comprises transmitting signals using said one or two beam ports.

## Claims

### Claim at position 1

1-18. (canceled)

### Claim 19

A method for beam forming using an antenna array comprising dual polarized elements, the method comprising:
generating one or two beam ports:
wherein the one or two beam ports are defined by combining at least two non-overlapping subarrays;
wherein each subarray has two subarray ports, the two subarray ports having identical power patterns and mutually orthogonal polarization;
wherein the at least two non-overlapping subarrays are combined via expansion weights;
wherein the expansion weights map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays; and
wherein at least some of the expansion weights have identical non-zero magnitude and are related in phase to form a transmission lobe;
wherein the expansion weights are collected in an expansion matrix and are determined such that the expansion matrix is spatially white; and
transmitting signals using the one or two beam ports.

### Claim 20 (depends on 19)

The method of claim 19, wherein the expansion weights map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays.

### Claim 21 (depends on 19)

The method of claim 19, wherein:
there are two beam ports; and
the expansion weights are defined to keep the polarization of the two beam ports mutually orthogonal.

### Claim 22 (depends on 19)

The method of claim 19, wherein:
there are two beam ports; and
the expansion weights map the two beam ports to products of powers of 2, 6, or 10 subarrays per dimension.

### Claim 23 (depends on 19)

The method of claim 19, wherein
there is one beam port; and
the expansion weights map the beam port to powers of 2, 6, and/or 10 times 1, 3, or 5 subarrays.

### Claim 24 (depends on 19)

The method of claim 19, wherein the subarrays are further expanded by further expansion weights before defining the one or two beam ports.

### Claim 25 (depends on 19)

The method of claim 19, wherein the expansion weights are determined such that all elements in a matrix defined by the sum of the magnitude squared of the two-dimensional discrete Fourier transform of a first expansion weight matrix applied to a first of the subarray ports and the magnitude squared of the two-dimensional discrete Fourier transform of a second expansion weight matrix applied to a second of the subarray ports have the same value.

### Claim 26 (depends on 19)

The method of claim 19, wherein the expansion weights are determined such that:
|DFT(ea)|2+|DFT(eb)|2=k·Jrc
where DFT(ea) and DFT(eb) denote the discrete Fourier transforms of ea and eb, respectively, where ea and eb are the total expansion matrices applied to the subarray ports a and b, respectively, where a is first of the subarray ports, where b is a second of the subarray ports, where k is a constant, and where Jrc is an all-one matrix having r rows and c columns.

### Claim 27 (depends on 19)

The method of claim 19, wherein the at least two non-overlapping subarrays together cover all elements of the antenna array.

### Claim 28 (depends on 19)

The method of claim 19, wherein the expansion weights of the at least two sub-arrays are added to generate one of the one or two beam ports.

### Claim 29 (depends on 19)

The method of claim 19, wherein the expansion weights for a port a with a first polarization are determined as:
ea
2
=
[
e
i

π
4

[
1

-
1
]
Z
12
]
,

ea
6
=
[
e
i

π
4

[
3
1
0
0
1
3
]
Z
32
]
,

ea
10
=
[
e
i

π
4

[
-
2
0
-
1
3
0
0
3
-
1
0
-
2
]
Z
52
]
,
where eam denotes the expansion weights for mapping one beam port of the one or two beam ports to multiples of m subarrays, and where Zrc is an all-zero matrix having r rows and c columns.

### Claim 30 (depends on 29)

The method of claim 29, wherein the expansion weights for a port b with a second polarization, orthogonal to the first polarization, is determined as:
ebm=flipud([eam(:,2)−eam(:,1)]*)
where eam(:,c) denotes column c of eam, where * denotes complex conjugate, and where flipud(x) reverses the row order of x.

### Claim 31 (depends on 19)

The method of claim 19, wherein the signals comprise at least one of broadcast information and system information.

### Claim 32 (depends on 19)

The method of claim 19, wherein there are two beam ports; and wherein the expansion weights map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays, and the two beam ports have mutually orthogonal polarizations in any direction.

### Claim 33

An antenna arrangement, comprising:
an antenna array comprising dual polarized elements for beam forming;
processing circuitry configured to cause the antenna array to:
generate one or two beam ports:
wherein the beam ports are defined by combining at least two non-overlapping subarrays;
wherein each subarray has two subarray ports, the two subarray ports having identical power patterns and mutually orthogonal polarization;
wherein the at least two non-overlapping subarrays are combined via expansion weights;
wherein the expansion weights map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays;
wherein at least some of the expansion weights have identical non-zero magnitude and are related in phase to form a transmission lobe;
wherein the expansion weights are collected in an expansion matrix and are determined such that the expansion matrix is spatially white;
transmit signals using the one or two beam ports.

### Claim 34

A network node comprising:
an antenna arrangement comprising an antenna array and processing circuitry;
wherein the antenna array comprises dual polarized elements for beam forming;
wherein the processing circuitry is configured to cause the antenna array to:
generate one or two beam ports:
wherein the beam ports are defined by combining at least two non-overlapping subarrays;
wherein each subarray has two subarray ports, the two subarray ports having identical power patterns and mutually orthogonal polarization;
wherein the at least two non-overlapping subarrays are combined via expansion weights;
wherein the expansion weights map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays;
wherein at least some of the expansion weights have identical non-zero magnitude and are related in phase to form a transmission lobe;
wherein the expansion weights are collected in an expansion matrix and are determined such that the expansion matrix is spatially white;
transmit signals using the one or two beam ports.

### Claim 35

A wireless device, comprising:
an antenna arrangement comprising an antenna array and processing circuitry;
wherein the antenna array comprises dual polarized elements for beam forming;
wherein the processing circuitry is configured to cause the antenna array to:
generate one or two beam ports:
wherein the beam ports are defined by combining at least two non-overlapping subarrays;
wherein each subarray has two subarray ports, the two subarray ports having identical power patterns and mutually orthogonal polarization;
wherein the at least two non-overlapping subarrays are combined via expansion weights;
wherein the expansion weights map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays;
wherein at least some of the expansion weights have identical non-zero magnitude and are related in phase to form a transmission lobe;
wherein the expansion weights are collected in an expansion matrix and are determined such that the expansion matrix is spatially white;
transmit signals using the one or two beam ports.

### Claim 36

A non-transitory computer readable recording medium storing a computer program product for beam forming using an antenna array comprising dual polarized elements, the computer program product comprising software instructions which, when run on processing circuitry, causes the antenna array to:
generate one or two beam ports:
wherein the beam ports are defined by combining at least two non-overlapping subarrays;
wherein each subarray has two subarray ports, the two subarray ports having identical power patterns and mutually orthogonal polarization;
wherein the at least two non-overlapping subarrays are combined via expansion weights;
wherein the expansion weights map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays;
wherein at least some of the expansion weights have identical non-zero magnitude and are related in phase to form a transmission lobe;
wherein the expansion weights are collected in an expansion matrix and are determined such that the expansion matrix is spatially white; and
transmit signals using the one or two beam ports.