Low PAPR SSB Design via DFT Spreading
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Solution Overview
Problem
In wireless communications, especially in higher frequency ranges, factors like high phase noise and power amplifier non-linearity can lead to waveform distortion, causing issues with decoding synchronization signals, particularly due to peak to average power ratio (PAPR) limitations, which affect the reliability and coverage of communications between base stations and user equipment.
Innovation Solution
Configuring synchronization signal blocks (SSBs) with low PAPR waveforms, including configurations for primary synchronization signals (PSS), physical broadcast channels (PBCH), and secondary synchronization signals (SSS), using discrete Fourier transform (DFT) spreading and specific sequence lengths, to maintain reliable downlink communications and extend coverage without increasing antenna complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional waveforms are used in higher frequency ranges, then communication can be established, but waveform distortion occurs due to high PAPR causing decoding failures and reduced reliability
Solution Approach 1:
The patent changes the waveform parameters by applying DFT spreading to the synchronization signal block, transforming the conventional waveform into a low-PAPR waveform. This parameter change reduces the peak to average power ratio, thereby minimizing waveform distortion caused by power amplifier non-linearity and improving decoding reliability in higher frequency ranges
2Length of stationary object
If transmit power is increased to improve coverage, then coverage area expands, but waveform distortion increases due to PAPR limitations
Solution Approach 1:
By changing the waveform parameter through DFT spreading to achieve low PAPR, the system enables higher average transmit powers to be used without causing excessive waveform distortion. This allows coverage area to be extended while maintaining signal quality and avoiding the harmful effects of high PAPR at elevated power levels
3Reliability
If additional antenna arrays are used to improve coverage, then coverage and reliability improve, but device complexity and cost increase
Solution Approach 1:
The patent substitutes the mechanical approach of adding more antenna elements with a signal processing approach - applying DFT spreading to create low-PAPR waveforms. This replaces the need for additional antenna arrays with a waveform design solution, thereby improving communication reliability without increasing hardware complexity or cost
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of low PAPR SSB configurations improves communication reliability and coverage by maintaining peak transmit power while reducing distortion, allowing for higher average transmit powers and increased coverage without the need for additional antenna arrays, thus simplifying the communication structure.
Implementation Method 1
A synchronization signal block (SSB) may be passed through a discrete Fourier transform (DFT) spreading operation in order to minimize an associated peak to average power ratio (PAPR)
Data Source
AI summary
Methods, systems, and devices for synchronization signal block (SSB) design are described to enable a base station to configure and transmit an SSB with a peak to average power ratio (PAPR) below a threshold. A low-PAPR SSB configuration may include a primary synchronization signal (PSS), a physical broadcast channel (PBCH), and a secondary synchronization signal (SSS). A user equipment (UE) may use the low-PAPR SSB configuration to monitor for and decode the SSB and begin communications with the base station. A low-PAPR SSB configuration may indicate available PSS sequences and lengths. A low-PAPR SSB configuration may also indicate multiplexing and symbol arrangements for a PBCH, DMRS, and SSS, and low-PAPR communications methods. A configuration may further indicate reference signal configurations, information for different communication types, subcarrier spacing, a number of symbols of an SSB, or a number of available SSBs and associated groups.