US-12628182-B2 - User equipment performing blind decoding and operating method thereof

Abstract

A method of wireless communication is described. A user equipment performs data communication based on a polar code with a base station by obtaining a physical downlink control channel (PDCCH) candidate from at least one search area in a frequency band for the data communication, performing error detection on frozen bits of the PDCCH candidate, determining whether the PDCCH candidate is a valid PDCCH candidate based on a result of the error detection, and selectively performing polar decoding on the PDCCH candidate based on a determination result of the valid PDCCH candidate.

Inventors

• Daeson KIM
• Juhyuk IM

Assignees

• SAMSUNG ELECTRONICS CO., LTD.

Dates

Publication Date

20260512

Application Date

20230711

Priority Date

20220714

Claims (19)

1. 1 . A method of data communication, the method comprising: obtaining a physical downlink control channel (PDCCH) candidate from at least one search area in a frequency band for the data communication; performing error detection on frozen bits of the PDCCH candidate; determining whether the PDCCH candidate is a valid PDCCH candidate based on a result of the error detection; and selectively performing polar decoding on the PDCCH candidate based on a determination result of the valid PDCCH candidate, wherein the performing of the error detection further comprises: performing a hard decision on a log likelihood ratio (LLR) of the PDCCH candidate; first multiplying a result of the hard decision by a generator matrix used for polar encoding; and generating a frozen bit error ratio (FBER) from a result of the first multiplying.
2. 2 . The method of claim 1 , wherein generating the FBER comprises: counting a first number of bits that are not zero among frozen bits in the result of the first multiplying; and generating a ratio between the counted first number and the number of frozen bits as the FBER.
3. 3 . The method of claim 2 , wherein the number of frozen bits is variable depending on a bit size of DCI.
4. 4 . The method of claim 1 , wherein: determining whether the PDCCH candidate is a valid PDCCH candidate comprises comparing the FBER with a first reference value; and determining the PDCCH candidate as the valid PDCCH candidate when the FBER is less than the first reference value.
5. 5 . The method of claim 1 , wherein, when the FBER is equal to or greater than a first reference value, performing of the error detection comprises performing frozen bit masking on the result of the first multiplying; second multiplying a result of the frozen bit masking by the generator matrix; and generating a regenerated frozen bit error ratio (RFBER) from a result of the second multiplying.
6. 6 . The method of claim 5 , wherein the generating the RFBER further comprises: counting a second number of bits having different values between the frozen bits in a result of the second multiplying and the frozen bits in the hard decision result; and generating as the RFBER a ratio between the counted second number and a number of frozen bit errors of the PDCCH candidate.
7. 7 . The method of claim 5 , wherein: determining whether the PDCCH candidate is a valid PDCCH candidate comprises comparing the RFBER with a second reference value; and determining the PDCCH candidate as the valid PDCCH candidate when the RFBER is less than the second reference value.
8. 8 . The method of claim 1 , wherein, in the selectively performing polar decoding on the PDCCH candidate when it is determined that the PDCCH candidate is not the valid PDCCH candidate, polar decoding for the PDCCH candidate is omitted, and when it is determined that the PDCCH candidate is the valid PDCCH candidate, the polar decoding is performed on the PDCCH candidate.
9. 9 . The method of claim 1 , wherein the performing of the error detection comprises: checking whether a puncturing technique is applied to the PDCCH candidate; and selectively excluding some of the frozen bits from detecting the error based on a result of the checking.
10. 10 . The method of claim 1 , further comprising: measuring a quality of a log likelihood ratio (LLR) of the PDCCH candidate; and determining whether the PDCCH candidate is the valid PDCCH candidate based on the quality of the LLR.
11. 11 . The method of claim 10 , wherein the determining whether the PDCCH candidate is the valid PDCCH candidate comprises comparing the quality of the LLR with a third reference value; and determining the PDCCH candidate as the valid PDCCH candidate when the quality of the LLR exceeds the third reference value.
12. 12 . The method of claim 11 , wherein, the determining whether the PDCCH candidate is the valid PDCCH candidate based on the quality of the LLR is performed prior to the performing of the error detection and the determining whether the PDCCH candidate is the valid PDCCH candidate based on the error detection result; and when the quality of the LLR exceeds the third reference value, the performing of the error detection and the determining whether the PDCCH candidate is the PDCCH valid candidate based on the error detection result are omitted.
13. 13 . A user equipment comprising: a transceiver configured to receive data based on a polar code from a base station; and a processor configured to perform error detection on frozen bits of a physical downlink control channel (PDCCH) candidate, determine whether the PDCCH candidate is a valid PDCCH candidate based on a result of the error detection, and perform selective polar decoding on the PDCCH candidate based on a determination result of the valid PDCCH candidate to obtain DCI from the data, wherein the processor is configured to perform hard decision on a log likelihood ratio (LLR) of the PDCCH candidate, first multiply a result of the hard decision by a generator matrix used for polar encoding, generate a frozen bit error rate (FBER) from a result of the first multiplying, and determine whether the PDCCH candidate is the valid PDCCH candidate based on the FBER.
14. 14 . The user equipment of claim 13 , wherein the FBER is a ratio between a first number of bits that are not zero among the frozen bits in the result of the first multiplication and the number of frozen bits.
15. 15 . The user equipment of claim 13 , wherein the processor is configured to perform frozen bit masking on a result of the first multiplying, second multiply a result of the frozen bit masking by the generator matrix, generate a regenerated frozen bit error rate (RFBER) from a result of the second multiplication, and determine whether the PDCCH candidate is the valid PDCCH candidate by additionally considering the RFBER.
16. 16 . The user equipment of claim 15 , wherein the RFBER is a ratio between a second number of bits having different values between frozen bits in a result of the second multiplication and frozen bits in a result of the hard decision and a number of frozen bit errors of the PDCCH candidate.
17. 17 . The user equipment of claim 13 , wherein the processor is configured to measure a quality of a log likelihood ratio (LLR) of the PDCCH candidate and determine whether the PDCCH candidate is the valid PDCCH candidate by preferentially considering the quality of the LLR.
18. 18 . A method of a user equipment, the method comprising: performing polar code-based error detection for each of a plurality of physical downlink control channel (PDCCH) candidates for obtaining DCI for data communication; determining valid PDCCH candidates from among the plurality of PDCCH candidates based on a result of the error detection; and performing blind decoding on the valid PDCCH candidates, wherein for each of the plurality of PDCCH candidates, the performing of the polar code-based error detection comprises: performing a hard decision on a log likelihood ratio (LLR) of the PDCCH candidate; first multiplying a result of the hard decision by a generator matrix used for polar encoding; and generating a frozen bit error ratio (FBER) from a result of the first multiplying.
19. 19 . The method of claim 18 , wherein the generating of the FBER comprises: counting a first number of bits that are not zero among frozen bits in the result of the first multiplying; and generating a ratio between the counted first number and the number of frozen bits as the FBER.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2022-0087090, filed on Jul. 14, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. BACKGROUND The present disclosure relates to wireless communication, and particularly to a user equipment for performing blind decoding in an arbitrary network-based communication, and an operating method thereof. A related downlink control information (DCI) supports transmission of downlink and uplink transmission channels in a communication system. The user equipment may receive a physical downlink control channel (PDCCH) from the base station, perform decoding on the PDCCH, and receive DCI based on the decoding result. The PDCCH may include various formats and the user equipment may not determine the format selected by the base station in advance. Additionally, in the PDCCH, since a time/frequency resource defined as a search space may be transmitted through an arbitrary resource in a set, the exact time/frequency resource through which the PDCCH is transmitted is not determined in advance by the user equipment. In some cases, the PDCCH is decoded based on blind decoding. Blind decoding refers to decoding performed by the user equipment on a plurality of PDCCH candidates with at least one control channel element (CCE) in a plurality of search spaces. The user equipment may determine that the DCI included in the corresponding PDCCH candidate is valid when a cyclic redundancy check (CRC) is passed in the process of decoding any one of the plurality of PDCCH candidates. Accordingly, the user equipment processes scheduling assignment, scheduling grant, and the like included in the corresponding DCI. The number of PDCCH candidates may increase due to an increase in the number of search spaces in next generation communication. The time and power required for blind decoding in the user equipment increases accordingly, which limits the performance of the user equipment. Therefore, there is a need in the art for improved methods of decoding PDCCH candidates. SUMMARY The present disclosure describes a user equipment for improving power consumption and time required for blind decoding, and a method of operating the same. The user equipment may determine valid physical downlink control channel (PDCCH) candidates from among the PDCCH candidates and perform selective blind decoding on the valid PDCCH candidates. According to an aspect of the present disclosure, a method of a user equipment performing data communication based on a polar code with a base station is provided, including obtaining a PDCCH candidate from at least one search area in a frequency band for the data communication, performing error detection on frozen bits of the PDCCH candidate, determining whether the PDCCH candidate is a valid PDCCH candidate based on a result of the error detection, and selectively performing polar decoding on the PDCCH candidate based on a determination result of the valid PDCCH candidate. According to another aspect of the present disclosure, a user equipment including a transceiver configured to receive data based on a polar code from a base station and a processor is provided. The user equipment is configured to perform error detection on frozen bits of a PDCCH candidate, determine whether the PDCCH candidate is a valid PDCCH candidate based on a result of the error detection, and perform selective polar decoding on the PDCCH candidate based on a determination result of the valid PDCCH candidate to obtain downlink control information from the data. According to another aspect of the present disclosure, a method of a user equipment performing data communication based on a polar code with a base station including performing polar code-based error detection for each of a plurality of physical downlink control channel (PDCCH) candidates for obtaining DCI for the data communication, determining valid PDCCH candidates from among the plurality of PDCCH candidates based on a result of the error detection, and performing blind decoding on the valid PDCCH candidates. According to another aspect of the present disclosure, a user equipment receives a plurality of PDCCH candidates from a base station. In some cases, the user equipment performs frozen bit error detection on the plurality of PDCCH candidates to obtain a frozen bit error ratio (FBER). Further, the user equipment selects a valid PDCCH candidate from the plurality of PDCCH candidates based on the FBER and decodes the valid PDCCH candidate. In some aspects, the method comprises performing a regenerated frozen bit error detection on the plurality of PDCCH candidates to obtain a regeneration frozen bit error ratio (RFBER), wherein the valid PDCCH candidate is selected based on the RFBER. In some aspects, the method further comprises measuring a log-likelihood ratio (LLR) quali