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EP-4738771-A1 - MODEM CHIP FOR ADJUSTING LOG LIKELIHOOD RATIO BY INFERRING CHANNEL ESTIMATION ERROR AND OPERATING METHOD OF THE MODEM CHIP

EP4738771A1EP 4738771 A1EP4738771 A1EP 4738771A1EP-4738771-A1

Abstract

A modem chip includes a radio frequency integrated circuit (RFIC) configured to receive a data signal and a reference signal through a precoding resource block group (PRG) including a plurality of first subcarriers to which the data signal is allocated and a plurality of second subcarriers to which the reference signal is allocated, and a processor configured to calculate a delay spread value of the data signal by using the reference signal, determine one of two threshold values, adjacent to the delay spread value, of a plurality of threshold values as a maximum threshold value corresponding to the delay spread value, and calculate an adjustment log likelihood ratio (LLR) of each of at least one first subcarrier among the plurality of first subcarriers, based on an adjustment coefficient corresponding to the maximum threshold value.

Inventors

  • KIM, JOOHAN
  • JUNG, Youngseok
  • JUNG, JAEHOON

Assignees

  • Samsung Electronics Co., Ltd.

Dates

Publication Date
20260506
Application Date
20250902

Claims (15)

  1. A modem chip comprising: a radio frequency integrated circuit, RFIC, configured to receive (S100) a data signal and a reference signal through a precoding resource block group, PRG, including a plurality of first subcarriers to which the data signal is allocated and a plurality of second subcarriers to which the reference signal is allocated; and a processor configured to: calculate (S200) a delay spread value of the data signal by using the reference signal, determine (S300) one of two threshold values, adjacent to the delay spread value, of a plurality of threshold values as a maximum threshold value corresponding to the delay spread value, and calculate (S400) an adjustment log likelihood ratio, LLR, of each of at least one first subcarrier among the plurality of first subcarriers, based on an adjustment coefficient corresponding to the maximum threshold value.
  2. The modem chip of claim 1, wherein the adjustment LLR is less than a raw LLR, corresponding to the adjustment LLR, of each of the at least one first subcarrier.
  3. The modem chip of claim 1 or claim 2, wherein the adjustment LLR is reduced as a number of the plurality of second subcarriers decreases.
  4. The modem chip of any preceding claim, wherein the adjustment LLR is reduced as the delay spread value increases.
  5. The modem chip of any preceding claim, further comprising: a memory configured to store the plurality of threshold values, wherein the at least one first subcarrier corresponds to a subcarrier having a lowest frequency among the plurality of first subcarriers in the PRG or a subcarrier having a highest frequency among the plurality of first subcarriers.
  6. The modem chip of any preceding claim, wherein the processor is configured further to: calculate a channel estimation value of each of the at least one first subcarrier; and calculate the adjustment LLR based on the channel estimation value of each of the at least one first subcarrier without calculating a channel estimation error of the channel estimation value.
  7. The modem chip of any preceding claim, wherein the delay spread value is a root mean square delay spread value.
  8. An operating method of a modem chip, the operating method comprising: receiving (S100) a data signal and a reference signal through a precoding resource block group, PRG, including a plurality of first subcarriers to which the data signal is allocated and a plurality of second subcarriers to which the reference signal is allocated; calculating (S200) a delay spread value of the data signal by using the reference signal; determining (S300) one of two threshold values, adjacent to the delay spread value, of a plurality of threshold values as a maximum threshold value corresponding to the delay spread value; and calculating (S400) an adjustment log likelihood ratio, LLR, of each of at least one first subcarrier among the plurality of first subcarriers, based on an adjustment coefficient corresponding to the maximum threshold value.
  9. The operating method of claim 8, wherein the adjustment LLR is less than a raw LLR, corresponding to the adjustment LLR, of each of the at least one first subcarrier.
  10. The operating method of claim 8 or claim 9, wherein the adjustment LLR is reduced as a number of the plurality of second subcarriers decreases.
  11. The operating method of any of claims 8-10, wherein the adjustment LLR is reduced as the delay spread value increases.
  12. The operating method of any of claims 8-11, wherein the at least one first subcarrier corresponds to a subcarrier having a lowest frequency among the plurality of first subcarriers in the PRG or a subcarrier having a highest frequency among the plurality of first subcarriers.
  13. The operating method of any of claims 8-12, further comprising: calculating a channel estimation value of each of the at least one first subcarrier, wherein the calculating of the adjustment LLR comprises: calculating the adjustment LLR, based on the channel estimation value and the adjustment coefficient without calculating a channel estimation error of the channel estimation value.
  14. A modem chip comprising: a radio frequency integrated circuit, RFIC, configured to receive (S100) a data signal and a reference signal through a precoding resource block group, PRG, including a plurality of first subcarriers to which the data signal is allocated and a plurality of second subcarriers to which the reference signal is allocated; and a processor configured to: calculate a delay spread value (S200) of the data signal by using the reference signal, and determine an adjustment coefficient so that an adjusted log likelihood ratio, LLR, of each of at least one first subcarrier among the plurality of first subcarriers is inversely proportional to the delay spread value, wherein the adjusted LLR corresponds to an LLR of each of the at least one first subcarrier adjusted using the adjustment coefficient.
  15. The modem chip of claim 14, wherein the adjusted LLR of the at least one first subcarrier is reduced as a number of the plurality of second subcarriers decreases.

Description

BACKGROUND The inventive concept relates to a modem chip and an operating method thereof, and more particularly, to a modem chip and an operating method thereof, which may infer a channel estimation error of a reception signal based on delay spread and/or a reference signal, and may adjust a log likelihood ratio based on an inference result, and thus, may enhance the accuracy of decoding. Recently, as wired/wireless communication technology and smart device-related technology advance rapidly, a wireless communication system needs the high accuracy of decoding of a signal received by a receiver. As the reliability of a log likelihood ratio (LLR) increases, a received signal may be accurately decoded. In this case, as a channel estimation error of an estimated channel is large, the channel estimation error may increase, and due to this, the reliability of an LLR may be reduced, causing a reduction in performance of a wireless communication system. Generally, a channel estimation error may increase as the amount of channel change between subcarriers is large (frequency selectivity), or the number of resource elements (REs) to which a reference signal is allocated is reduced. Therefore, a method of enhancing the performance of decoding by inferring a channel estimation error to adjust an LLR, based on the amount of channel change and/or the reference signal, is required. SUMMARY The inventive concept provides a modem chip and an operating method thereof, which may infer a channel estimation error to adjust a log likelihood ratio and may thus enhance the accuracy of decoding. The object of the inventive concept is not limited to the aforesaid, but other objects not described herein will be clearly understood by those of ordinary skill in the art from descriptions below. According to an embodiment of the present disclosure, a modem chip includes a radio frequency integrated circuit (RFIC) configured to receive a data signal and a reference signal through a precoding resource block group (PRG) including a plurality of first subcarriers to which the data signal is allocated and a plurality of second subcarriers to which the reference signal is allocated, and a processor configured to calculate a delay spread value of the data signal by using the reference signal, determine one of two threshold values, adjacent to the delay spread value, of a plurality of threshold values as a maximum threshold value corresponding to the delay spread value, and calculate an adjustment log likelihood ratio (LLR) of each of at least one first subcarrier among the plurality of first subcarriers, based on an adjustment coefficient corresponding to the maximum threshold value. According to an aspect of the present disclosure, an operating method of a modem chip includes receiving a data signal and a reference signal through a precoding resource block group (PRG) including a plurality of first subcarriers to which the data signal is allocated and a plurality of second subcarriers to which the reference signal is allocated, calculating a delay spread value of the data signal by using the reference signal, determining one of two threshold values, adjacent to the delay spread value, of a plurality of threshold values as a maximum threshold value corresponding to the delay spread value, and calculating an adjustment log likelihood ratio (LLR) of each of at least one first subcarrier among the plurality of first subcarriers, based on an adjustment coefficient corresponding to the maximum threshold value. According to an aspect of the present disclosure, a modem chip includes a radio frequency integrated circuit (RFIC) configured to receive a data signal and a reference signal through a precoding resource block group (PRG) including a plurality of first subcarriers to which the data signal is allocated and a plurality of second subcarriers to which the reference signal is allocated, and a processor configured to calculate a delay spread value of the data signal by using the reference signal, and determine an adjustment coefficient so that an adjusted log likelihood ratio (LLR) of each of at least one first subcarrier among the plurality of first subcarriers is inversely proportional to the delay spread value. The adjusted LLR corresponds to an LLR of each of the at least one first subcarrier adjusted using the adjustment coefficient. At least some of the above and other features of the invention are set out in the claims. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which: FIG. 1 is a block diagram illustrating a wireless communication system according to an embodiment;FIG. 2 is a block diagram illustrating a wireless communication device according to an embodiment;FIG. 3 is a block diagram illustrating a log likelihood ratio (LLR) adjustment module adjusting an LLR, according to an embodiment;FIG. 4 is a graph for des