Pulse-shaping filters for improving the spectral efficiency of broadband satellite systems

Patent metadata

Field	Value
Publication number	US-12477392-B2
Application number	US-202218148565-A
Country	US
Kind code	B2
Filing date	Dec 30, 2022
Priority date	Dec 30, 2022
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

Systems and methods are described for generating and implementing pulse-shaping filters for efficient utilization of limited spectral resources in wireless communication systems. Wireless communication systems operating at high spectral efficiency conventionally use pulse shaping filters that rely on Nyquist waveforms for good main lobe performance with low inter-symbol interference (ISI) power. Conventional uses of non-Nyquist waveforms typically involve an orthogonalization process to convert those non-Nyquist waveforms to Nyquist waveforms for ISI free performance. Embodiments of pulse shaping filters described herein generate a non-Nyquist partial response (NNPR) transmit filter and/or matched receive filter based on applying a tunable second-weighted orthogonalization to a tunable first-weighted non-Nyquist waveform to obtain a pulse-shaping waveform with parametric control over throughput and power penalty.

First claim

What is claimed is:

1 . A system for communicating a data signal in a wireless communication network, the system comprising:
a transmitter to transmit a pulse-shaped signal over a wireless channel of the wireless communication network, the transmitter having:
a front-end configured to convert a stream of information bits to a sequence of symbols and to modulate the sequence of symbols onto the data signal; and
a non-Nyquist partial response (NNPR) filter configured to pulse-shape the data signal with a non-Nyquist pulse-shaping waveform to generate the pulse-shaped signal,
wherein the non-Nyquist pulse-shaping waveform is generated by weighting a non-Nyquist waveform as a function of a first tunable weighting factor to generate a weighted non-Nyquist waveform, and
wherein the non-Nyquist pulse-shaping waveform is generated by applying weighted orthogonalization to the weighted non-Nyquist waveform as a function of a second tunable weighting factor, the second tunable weighting factor controlling a non-zero amount of inter-symbol interference (ISI) in the non-Nyquist pulse-shaping waveform; and
a receiver to receive the pulse-shaped signal via the wireless channel, the receiver having:
a matched filter configured to filtering the received pulse-shaped signal in accordance with pulse-shaping by the NNPR filter.

2 . The system of claim 1 , wherein:
the wireless channel is associated with a target throughput characteristic and a target power penalty characteristic; and
the first tunable weighting factor and the second tunable weighting factor are set, such that the non-Nyquist pulse-shaping waveform is generated to yield a throughput at least meeting the target throughput characteristic accompanied by a power penalty at least meeting the target power penalty characteristic.

3 . The system of claim 1 , wherein:
the matched filter outputs a sequence of symbol samples based on sampling the received pulse-shaped signal; and the receiver further has a back-end to soft-convert the symbol samples to bit probabilities, and to de-interleave and decode the bit probabilities to obtain a stream of estimated bits corresponding to the stream of information bits.

4 . The system of claim 1 , wherein:
the NNPR filter is configured to have a frequency response of

ϕ
NNPR

(
f
)

=

S
G

(
f
)

⁢

/
[

∑

k
∈
ℤ

|

S
G

(

f
+

k
·

γ
f

(
k
)

T
s

)

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2

]

1
/
2

;

the weighted non-Nyquist waveform has a frequency response of

S
G

(
f
)

=

e

-

(

(

2
⁢
π
⁢
f

)

2

⁢

(

σ
⁢

T
s

)

2

)

;

σT s is the first tunable weighting factor; and
γ f (k) is the second tunable weighting factor.

5 . The system of claim 4 , wherein:
the wireless channel is associated with a target impulse response characteristic; and the first tunable weighting factor and the second tunable weighting factor are set, such that the non-Nyquist pulse-shaping waveform is generated to yield an impulse response, p NNPR,T (t), that at least meets the target impulse response characteristic and has a frequency-to-time-domain conversion of ϕ NNPR (f).

6 . The system of claim 1 , wherein the front-end comprises:
a forward error correction (FEC) block to apply a coding scheme to the stream of information bits to generate codebits; an interleaver block

Assignees

• Hughes Network Systems Llc

Inventors

• Seshadri Rohit Iyer
• Beidas Bassel F

Classifications

• H04L25/03834

  using pulse shaping · CPC title

• H04L1/0061

  Error detection codes · CPC title

• H04B7/18513

  Transmission in a satellite or space-based system · CPC title

• H03M7/02

  Conversion to or from weighted codes, i.e. the weight given to a digit depending on the position of the digit within the block or code word · CPC title

• H04B7/1851

  Systems using a satellite or space-based relay (H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576) · CPC title