Communication device for performing differential phase shift keying based on a plurality of previous signals and operating method thereof

Patent metadata

Field	Value
Publication number	US-12021671-B2
Application number	US-202217819984-A
Country	US
Kind code	B2
Filing date	Aug 16, 2022
Priority date	Aug 17, 2021
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

An method of determining a symbol according to a phase difference between input signals input in order of time may include calculating a first phase difference between a phase of a first previous signal received prior to a target signal and a phase of a second previous signal received prior to the first previous signal; calculating a second phase difference between a phase of the target signal and the phase of the second previous signal; calculating target likelihoods based on the first phase difference and the second phase difference; and determining an expected phase difference between the target signal and the first previous signal or an expected symbol for the target signal, based on the target likelihoods.

First claim

What is claimed is:

1. A method of determining a symbol according to a phase difference between input signals input in order of time, the method comprising:
calculating a first phase difference between a phase of a first previous signal and a phase of a second previous signal, wherein the first previous signal is received prior to a target signal, and wherein the second previous signal is received prior to the first previous signal;
calculating a second phase difference between a phase of the target signal and the phase of the second previous signal;
calculating, based on the first phase difference and the second phase difference, target likelihoods that a phase difference between the target signal and the first previous signal corresponds to each of a plurality of symbols; and
determining, based on the calculated target likelihoods, an expected symbol of the plurality of symbols for the target signal or an expected phase difference between the target signal and the first previous signal.

2. The method of claim 1 , further comprising:
obtaining hard-decision phase differences for one or more received signals up to the second previous signal; and
determining the phase of the second previous signal by adding up the hard-decision phase differences.

3. The method of claim 1 , wherein the calculating of the target likelihoods comprises:
calculating a plurality of first likelihoods that the first phase difference corresponds to each of the plurality of symbols; and
calculating a plurality of second likelihoods that the second phase difference corresponds to each of the plurality of symbols.

4. The method of claim 3 , wherein the calculating of the first likelihoods comprises calculating a reliability of the first phase difference based on a code corresponding to the first phase difference, and
the calculating of the second likelihoods comprises calculating a reliability of the second phase difference, based on a code corresponding to the second phase difference.

5. The method of claim 4 , wherein:
the calculating of the first likelihoods comprises:
selecting a first likelihood corresponding to the reliability of the first phase difference from a lookup table; and
determining the selected first likelihood as at least some of the first likelihoods, and the calculating of the second likelihoods comprises:
selecting a second likelihood corresponding to the reliability of the second phase difference from the lookup table; and
determining the selected second likelihood as at least some of the second likelihoods.

6. The method of claim 3 , wherein:
the calculating of the first likelihoods comprises:
calculating first distances between the first phase difference and a phase corresponding to
each of the plurality of symbols; and
calculating the first likelihoods based on the first distances,

and the calculating of the second likelihoods comprises:
calculating second distances between the second phase difference and the phase corresponding to each of the plurality of symbols; and
calculating the second likelihoods, based on the second distances.

7. The method of claim 6 , wherein the first distances comprise a Euclidean squared distance between the phase corresponding to each of the plurality of symbols and the first phase difference, and
the second distances comprise a Euclidean squared distance between the phase corresponding to each of the plurality of symbols and the second phase difference.

8. The method of claim 3 , wherein the calculating of the target likelihoods comprises:
multiplying a likelihood that the first phase difference corresponds to a first symbol of the plurality of symbols by a likelihood that the second phase difference corresponds to a symbol obtained by combining the first symbol to a second symbol; and
determining the target likelihood that the phase difference between the target signal and the first previous signal corresponds to the second symbol by summing products of the first likelihood and the second likelihood when the first symbol corresponds to each of the plurality of symbols.

9. The method of claim 8 , wherein the determining of the expected phase difference or the expected symbol for the target signal comprises determining the expected symbol based on a combination of the target likelihoods predetermined per bit.

10. The method of claim 8 , wherein the determining of the expected phase difference or the expected symbol for the target signal comprises:
determining a first axis expected value and a second axis expected value, based on the target likelihood when the second symbol corresponds to each of the plurality of symbols; and
determining the expected phase difference, based on the first axis expected value and the second axis expected value.

11. The method of claim 10 , wherein the determining of the first axis expected value and the second axis expected value comprises:
determining the first axis expected value by summing products of the target likelihood corresponding to each of the plurality of symbols and a first axis value; and
determining the second axis expected value by summing products of the target likelihood corresponding to each of the plurality of symbols and a second axis value.

12. A method of determining a symbol corresponding to an input signal, the method comprising:
generating a first phase difference between a first input signal and a previous signal, wherein the first input signal is input in a previous sequence prior to a target sequence, and wherein the previous signal is received prior to the previous sequence;
generating a second phase difference between a second input signal and the previous signal, wherein the second input signal is input in the target sequence; and
determining an expected phase difference between the second input signal and the first input signal based on the first phase difference and the second phase difference.

13. The method of claim 12 , further comprising:
obtaining hard-decision phase differences for one or more signals received prior to receiving the previous signal; and
determining a phase of the previous signal by summing the hard-decision phase differences.

14. The method of claim 12 , wherein the determining of the expected phase difference comprises:
calculating target likelihoods that a phase difference between the second input signal and the first input signal corresponds to each of a plurality of symbols based on the first phase difference and the second phase difference; and
determining the expected phase difference based on the target likelihoods and a phase of a symbol corresponding to each target likelihood.

15. The method of claim 14 , wherein the calculating of the target likelihoods comprises:
calculating a plurality of first likelihoods that the first phase difference corresponds to each of the plurality of symbols; and
calculating a plurality of second likelihoods that the second phase difference corresponds to each of the plurality of symbols.

16. The method of claim 15 , wherein the calculating of the first likelihoods comprises calculating a reliability of the first phase difference, based on a code corresponding to the first phase difference, and
the calculating of the second likelihoods comprises calculating a reliability of the second phase difference, based on a code corresponding to the second phase difference.

17. The method of claim 16 , wherein:
the calculating of the first likelihoods comprises:
selecting a first likelihood corresponding to the reliability of the first phase difference from a lookup table;

Assignees

• Samsung Electronics Co Ltd

Inventors

• Baik Jonghyun

Classifications

• H04L27/32

  Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26 · CPC title

• H03D13/001

  in which a pulse counter is used followed by a conversion into an analog signal · CPC title

• H04L25/061

  providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of DC offset (removal of DC offset in coupling arrangements H04L25/029, H04L25/0296) · CPC title

• H04L27/3845

  using non - coherent demodulation, i.e. not using a phase synchronous carrier · CPC title

• H04L25/067

  providing soft decisions, i.e. decisions together with an estimate of reliability (H04L25/068 and H04L25/069 take precedence; sequence estimation techniques H04L25/03178) · CPC title