Reference signal design with Zadoff-Chu sequences

Patent metadata

Field	Value
Publication number	US-11356313-B2
Application number	US-202017009581-A
Country	US
Kind code	B2
Filing date	Sep 1, 2020
Priority date	Nov 11, 2016
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

Provided are methods of estimating a time delay and/or a frequency shift of a reference signal. Such methods include receiving a first reference signal that is generated using a first Zadoff-Chu (ZC) sequence, receiving a second reference signal that is generated using a second ZC sequence that is different than the first ZC sequence, and processing the first reference signal and the second reference signal to estimate at least one of the time delay and the frequency shift of the first reference signal and/or the second reference signal. The first ZC sequence is generated by a first root and the second ZC sequence is generated by a second root that is different than the first root.

First claim

What is claimed is:

1. A method of estimating a time delay and/or a frequency shift of a reference signal, the method comprising:
receiving a first reference signal that is generated using a first Zadoff-Chu (ZC) sequence, the first ZC sequence being generated using a first root;
receiving a second reference signal that is generated using a second ZC sequence that is different than the first ZC sequence, the second ZC sequence being generated using a second root that is different than the first root; and
processing the first reference signal and the second reference signal to estimate at least one of the time delay and the frequency shift of at least one of the first reference signal and the second reference signal, processing the first and second reference signals further comprising:
detecting the signals using a set of hypotheses of at least one of the time delay and frequency shift;
determining a best hypothesis of the set of hypotheses; and
estimating at least one of the time delay and frequency shift according to the best hypothesis.

2. The method of claim 1 , wherein processing the first reference signal comprises:
correlating the first reference signal with a local copy of the first reference signal to generate a first set of correlation results;
detecting a first correlation peak in the first set of correlation results;
estimating at least one of the time delay and the frequency shift of at least one of the reference signals using the detected first peak.

3. The method of claim 1 , wherein processing the first and second reference signals includes:
correlating the second reference signal with a local copy of the second reference signal to generate a second set of correlation results;
detecting a second correlation peak in the second set of correlation results; and
estimating at least one of the time delay and the frequency shift of at least one of the reference signals using the detected second correlation peak.

4. The method of claim 1 , wherein the first and second reference signals are time and/or frequency domain multiplexed.

5. The method of claim 1 , wherein the first ZC sequence has a same length as the second ZC sequence.

6. The method of claim 1 , wherein the second ZC sequence includes a cyclic shift relative to the first ZC sequence.

7. The method of claim 1 , wherein the second ZC sequence is generated as a conjugate of the first ZC sequence.

8. The method of claim 1 , wherein the first ZC sequence comprises a first length and the second ZC sequence comprises a second length that is different than the first length.

9. The method of claim 1 , wherein the first and second reference signals are downlink synchronization signals or arc uplink random access preambles.

10. A user equipment (UE) comprising:
a transceiver to provide wireless communication over a radio interface;
at least one processor coupled to the transceiver; and at least one memory coupled to the at least one processor and storing program code that when executed by the at least one processor causes the at least one processor to perform operations comprising:
receiving a first reference signal that is generated using a first Zadoff-Chu (ZC) sequence, the first ZC sequence being generated using a first root;
receiving a second reference signal that is generated using a second ZC sequence that is different than the first ZC sequence, the second ZC sequence being generated using a second root that is different than the first root; and
processing the first reference signal and the second reference signal to estimate at least one of a time delay and a frequency shift of at least one of the first reference signal and the second reference signal, processing the first and second reference signals further comprising:
detecting the signals using a set of hypotheses of at least one of the time delay and frequency shift;
determining a best hypothesis of the set of hypotheses; and
estimating at least one of the time delay and frequency shift according to the best hypothesis.

11. The user equipment of claim 10 , wherein processing the first reference signal comprises:
correlating the first reference signal with a local copy of the first reference signal to generate a first set of correlation results;
detecting a first correlation peak in the first set of correlation results;
estimating at least one of the time delay and the frequency shift of at least one of the reference signals using the detected first peak.

12. The user equipment of claim 10 , wherein processing the first and second reference signals includes:
correlating the second reference signal with a local copy of the second reference signal to generate a second set of correlation results;
detecting a second correlation peak in the second set of correlation results; and
estimating at least one of the time delay and the frequency shift of at least one of the reference signals using the detected second correlation peak.

13. The user equipment of claim 10 , wherein the first ZC sequence has a same length as the second ZC sequence.

14. The user equipment of claim 10 , wherein the second ZC sequence includes a cyclic shift relative to the first ZC sequence.

15. The user equipment of claim 10 , wherein the second ZC sequence is generated as a conjugate of the first ZC sequence.

16. A network node comprising:
a reference signal generation module that is configured to generate first and second reference signals using first and second ZC sequences, wherein the first ZC sequence is generated using a first root and the second ZC sequence is generated using a second root that is different than the first root; and
a reference signal transmission module that is configured to transmit the first and second reference signals to a radio node that is configured to estimate at least one of a time delay and a frequency shift by processing the first and second reference signals, processing the first and second reference signals further comprising:
detecting the signals using a set of hypotheses of at least one of the time delay and frequency shift;
determining a best hypothesis of the set of hypotheses; and
estimating at least one of the time delay and frequency shift according to the best hypothesis.

17. The network node of claim 16 , wherein the first ZC sequence has a same length as the second ZC sequence.

18. The network node of claim 16 , wherein the second ZC sequence includes a cyclic shift relative to the first ZC sequence.

Assignees

• Ericsson Telefon Ab L M

Inventors

• Lin Xingqin
• Adhikary Ansuman
• Khayrallah Ali S
• Koorapaty Havish
• Wang Yi-Pin Eric

Classifications

• H04W74/0833

  Random access procedures, e.g. with 4-step access · CPC title

• H04L27/2675 Primary

  Pilot or known symbols · CPC title

• H04L27/2613 Primary

  Structure of the reference signals · CPC title

• H04J13/0062

  Zadoff-Chu · CPC title

• H04L27/2657

  Carrier synchronisation · CPC title