Primary Synchronization Signal Detection With Differential DFT Processing

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Solution Overview

Problem

In high-frequency mobile communication systems, such as those operating in the terahertz band, the peak-to-average power ratio (PAPR) increases when using OFDM, and there is a challenge in maintaining a high probability of primary synchronization signal (PSS) detection, especially when the signal-to-noise ratio (SNR) is low.

Innovation Solution

The method involves differential decoding and discrete Fourier transform (DFT) processing of downlink signals to enhance PSS detection, including generating a reference signal (RS), performing DFT and inverse DFT on the PSS sequence, and adding a cyclic prefix to the DFT-s-OFDM symbol.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If OFDM is applied to downlink in high frequency band (terahertz band), then data service capability is improved, but peak-to-average power ratio (PAPR) increases

Engineering Contradiction:

Improvedata service capabilityVSAvoidpeak-to-average power ratio

Core Design Contradiction:

ProductivityVSPower

Solution Approach 1:

The patent applies DFT-s-OFDM which segments the OFDM signal processing into two stages: first performing DFT on data symbols to create spread spectrum, then performing OFDM modulation. This segmentation reduces the peak-to-average power ratio while maintaining the data service capability of OFDM in high frequency bands.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If conventional PSS transmission is used in high frequency band, then system simplicity is maintained, but PSS detection probability decreases when SNR is low

Engineering Contradiction:

Improvesystem simplicityVSAvoidPSS detection probability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent changes the PSS transmission parameters by applying differential encoding and DFT processing to the PSS sequence before transmission. This transforms the PSS signal characteristics to improve detection probability in low SNR conditions while maintaining system simplicity through standardized processing steps.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary processing on the PSS sequence by generating differential codes and applying DFT before the actual transmission. This preliminary action enhances the PSS detection capability when the signal arrives at the receiver, especially in low SNR environments, without adding complexity to the overall system architecture.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12563481B2Method of transmitting and receiving primary synchronization signal and apparatus thereof

Publication Date: 2026.02.24 LG ELECTRONICS INC

AI summary

Provided is a method performed by a user equipment (UE) in a wireless communication system including receiving a downlink signal, filtering the downlink signal, sampling the filtered downlink signal, performing differential decoding on the sampled downlink signal, obtaining a primary synchronization signal (PSS) sequence based on the downlink signal on which the differential decoding is performed, and obtaining cell area information based on the PSS sequence obtained based on the downlink signal on which the differential decoding is performed.