5G NR Zadoff-Chu Sequence Overview

This page provides an overview of the 5G NR Zadoff-Chu sequence. It includes a MATLAB simulation of a Zadoff-Chu sequence generator and explains its use in 5G NR technology.

Introduction

In 5G NR wireless systems, three main types of sequences are utilized:

• Zadoff-Chu sequence
• Gold sequence
• m-sequence

Gold sequences are typically used in CP-OFDM, Zadoff-Chu sequences are used in DFT-s-OFDM (specifically for SSS), and m-sequences are used in PSS.

Zadoff-Chu Sequence Use in 5G NR

Zadoff-Chu sequences have key applications in 5G NR, most notably:

• NR Random-Access Preambles (PRACH): They’re used to generate these preambles.

The Zadoff-Chu sequence’s popularity stems from its unique properties:

• Constant Amplitude: Maintains a constant amplitude both before and after Discrete Fourier Transform (DFT).
• Zero Cyclic Auto-Correlation: Exhibits zero cyclic auto-correlation.
• Low Cross-Correlation: Features low cross-correlation with other sequences.
• Low PAPR: For the PUSCH channel with DFT-S-OFDM physical layer, there is low Peak-to-Average Power Ratio.

The following PDF (as mentioned in TS 38.211 section 6.3.3) includes a snapshot of sequence generation for the random access channel.