US 12,445,339 B2Granted

Methods and systems for digital representation of encoded communications data and simplified evaluation of precoding in systems using phase-cyclical precoding

AssigneeWavestream Corporation

InventorJames Jordan Rosenberg

Life of this patent

Estimating the term…

Abstract

The present invention discloses the structure and operation of the “geometric shift transform” that enables the use of symbol alphabet code word representation of a user's binary data stream as the signal transport format from a central unit (modem) of a precoded OFDM system to a remote unit (the RF equipment). The invention simplifies the precoding transform (DFT) calculation, enables secure transmissions, and contemplates layer and resource block mapping operations in the central unit.

Claims6

Dependent claims

A method for implementing an M-point phase-cyclic transform used for precoding in a pre-coded orthogonal frequency-division multiplexing (OFDM) system, on a digital signal stream represented as a sequence of M k-bit symbol code words, wherein M is a number of code words and k is a number of bits in a code word, each code word representing one of 2k points in a base constellation of points on the complex plane, the method comprising:

a. generating a geometric shift table of stored values, having 2k rows and M columns, the geometric shift table defined by
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wherein each column is referenced by an index, n, and each of row is referenced by one of the 2k k-bit symbol code words, with n ranging from 0 for the first column to n=M−1 for the Mth column, and the φm exponents represent the phase factors characteristic of the phase-cyclic transform to be implemented
and wherein entries in the first column contain the complex numeric values from r[1]ejθ[1] to r[2k]ejθ[2k] corresponding to each point in the base constellation, ordered by the corresponding code word, and each subsequent column containing entries equaling the complex numeric value of each point in the base constellation multiplied by the corresponding phase factors, φn, that characterize said phase-cyclic transform, with each row entry ordered by the corresponding code word;
b. mapping each of the M symbol code words within said sequence of M k-bit symbol code words to an index, m, with m ranging from 0 to M−1;
c. forming a set of M outputs of the transform, referenced by an index, l, with l ranging from 0 to M−1;
and
d. evaluating each of said M outputs of the set of M outputs as a sum of M table entries, each said entry selected from the nth column of the geometric shift table where n is evaluated as a product of l and m, modulo M, and from the row corresponding to the code word assigned to the mth index, m ranging from 0 to M−1.

192 more elements

A method for transporting a digital signal stream within a pre-coded orthogonal frequency-division multiplexing (OFDM) transmission system, the method comprising:

a. encoding in a modem the digital signal stream as a sequence of M k-bit symbol code words, wherein M is a number of code words and k is a number of bits in a code word, each code word representing one of 2k points in a base constellation of points on the complex plane;
and
b. transporting from the modem the sequence of M k-bit symbol code words to a remote unit;
wherein, at the remote unit, the sequence of M k-bit symbol code words is input into an M-point phase-cyclic precoding transform implemented by
i. generating a geometric shift table of stored values, having 2k rows and M columns, the geometric shift table defined by
C
α
,
n
=
[
r
[
1
]
⁢
e
j
⁢
θ
[
1
]
⁢
e
j
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φ
0
r
[
1
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1
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1
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M
-
1
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2
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2
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]
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0
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1
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k
]
⁢
e
j
⁢
θ
[
2
k
]
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e
j
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φ
M
-
1
]
wherein each column is referenced by an index, n, and each of row is referenced by one of the 2k k-bit symbol code words, with n ranging from 0 for the first column to n=M−1 for the Mth column, and the φm exponents represent the phase factors characteristic of the phase-cyclic precoding transform to be applied,
and wherein entries in the first column contain the complex numeric values from r[1]ejθ[1] to r[2k]ejθ[2k] corresponding to each point in the base constellation, ordered by the corresponding code word, and each subsequent column containing entries equaling the complex numeric value of each point in the base constellation multiplied by the corresponding phase factors, φn, that characterize said phase-cyclic precoding transform, with each row entry ordered by the corresponding code word;
ii. mapping each of the M symbol code words within said sequence of M k-bit symbol code words to an index, m, with m ranging from 0 to M−1;
iii. forming a set of M outputs of the transform, referenced by an index, l, with l ranging from 0 to M−1;
and
iv. evaluating each of said M outputs of the set of M outputs as a sum of M table entries, each said entry selected from the nth column of the table where n is evaluated as a product of l and m, modulo M, and from the row corresponding to the code word assigned to the mth index, m ranging from 0 to M−1.

196 more elements

A non-transitory computer-readable storage medium storing one or more computer-readable programs which, when executed on a processor, configure the processor to carry out a method for computationally performing an M-point phase-cyclic transform used for precoding in a pre-coded orthogonal frequency-division multiplexing (OFDM) system, on a digital signal stream represented as a sequence of M k-bit symbol code words, wherein M is a number of code words and k is a number of bits in a code word, each code word representing one of 2k points in a base constellation of points on the complex plane, the method comprising:

a. generating a geometric shift table of stored values, having 2k rows and M columns, the geometric shift table defined by
C
α
,
n
=
[
r
[
1
]
⁢
e
j
⁢
θ
[
1
]
⁢
e
j
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φ
0
r
[
1
]
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e
j
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θ
[
1
]
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e
j
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φ
1
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r
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[
1
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M
-
1
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[
2
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k
]
⁢
e
j
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θ
[
2
k
]
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e
j
⁢
φ
M
-
1
]
wherein each column is referenced by an index, n, and each of row is referenced by one of the 2k k-bit symbol code words, with n ranging from 0 for the first column to n=M−1 for the Mth column, and the φm exponents represent the phase factors characteristic of the phase-cyclic transform to be applied,
and wherein entries in the first column contain the complex numeric values from r[1]ejθ[1] to r[2k]ejθ[2k] corresponding to each point in the base constellation, ordered by the corresponding code word, and each subsequent column containing entries equaling the complex numeric value of each point in the base constellation multiplied by the corresponding phase factors, φn, that characterize said phase-cyclic transform, with each row entry ordered by the corresponding code word;
b. mapping each of the M symbol code words within said sequence of M k-bit symbol code words to an index, m, with m ranging from 0 to M−1;
c. forming a set of M outputs of the transform, referenced by an index, l, with l ranging from 0 to M−1;
and
d. evaluating each of said M outputs of the set of M outputs as a sum of M table entries, each said entry selected from the nth column of the table where n is evaluated as a product of l and m, modulo M, and from the row corresponding to the code word assigned to the mth index, m ranging from 0 to M−1.

192 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/334,321Filed 13 Jun 2023
Published: US 2024/0422049 A119 Dec 2024
Granted: 14 Oct 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H04L 27/2636
Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation:…
H04L 27/2698
In combination with other modulation techniques: double density OFDM/OQAM system, e.g. OFDM/OQAM-IOTA system
G06F 17/142
Discrete Fourier transforms: fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm
H04L 5/0007
Time-frequency: the frequencies being orthogonal, e.g. OFDM or DMT

Family

US 2024/0422049 A1Pre-grant publication · published 19 Dec 2024
US 12,445,339 B2This patent

From the US filing history. Foreign family members aren’t listed.

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Abstract

a. generating a geometric shift table of stored values, having 2k rows and M columns, the geometric shift table defined by
C
α
,
n
=
[
r
[
1
]
⁢
e
j
⁢
θ
[
1
]
⁢
e
j
⁢
φ
0
r
[
1
]
⁢
e
j
⁢
θ
[
1
]
⁢
e
j
⁢
φ
1
…
r
[
1
]
⁢
e
j
⁢
θ
[
1
]
⁢
e
j
⁢
φ
M
-
1
r
[
2
]
⁢
e
j
⁢
θ
[
2
]
⁢
e
j
⁢
φ
0
r
[
2
]
⁢
e
j
⁢
θ
[
2
]
⁢
e
j
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φ
1
…
r
[
2
]
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e
j
⁢
θ
[
2
]
⁢
e
j
⁢
φ
M
-
1
⋮
⋮
⋱
⋮
r
[
2
k
]
⁢
e
j
⁢
θ
[
2
k
]
⁢
e
j
⁢
φ
0
r
[
2
k
]
⁢
e
j
⁢
θ
[
2
k
]
⁢
e
j
⁢
φ
1
…
r
[
2
k
]
⁢
e
j
⁢
θ
[
2
k
]
⁢
e
j
⁢
φ
M
-
1
]
wherein each column is referenced by an index, n, and each of row is referenced by one of the 2k k-bit symbol code words, with n ranging from 0 for the first column to n=M−1 for the Mth column, and the φm exponents represent the phase factors characteristic of the phase-cyclic transform to be implemented
and wherein entries in the first column contain the complex numeric values from r[1]ejθ[1] to r[2k]ejθ[2k] corresponding to each point in the base constellation, ordered by the corresponding code word, and each subsequent column containing entries equaling the complex numeric value of each point in the base constellation multiplied by the corresponding phase factors, φn, that characterize said phase-cyclic transform, with each row entry ordered by the corresponding code word;
b. mapping each of the M symbol code words within said sequence of M k-bit symbol code words to an index, m, with m ranging from 0 to M−1;
c. forming a set of M outputs of the transform, referenced by an index, l, with l ranging from 0 to M−1;
and
d. evaluating each of said M outputs of the set of M outputs as a sum of M table entries, each said entry selected from the nth column of the geometric shift table where n is evaluated as a product of l and m, modulo M, and from the row corresponding to the code word assigned to the mth index, m ranging from 0 to M−1.

192 more elements

Facts

Application

18/334,321Filed 13 Jun 2023

Published

US 2024/0422049 A119 Dec 2024

Granted

14 Oct 2025

Term ends

Not estimatedThe source records don’t support an estimate.

Classification9 codes

H04L 27/2636
Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation:…
H04L 27/2698
In combination with other modulation techniques: double density OFDM/OQAM system, e.g. OFDM/OQAM-IOTA system
G06F 17/142
Discrete Fourier transforms: fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm
H04L 5/0007
Time-frequency: the frequencies being orthogonal, e.g. OFDM or DMT