DMRS Signal Generation Using Pi/2-BPSK Modulation for PAPR Reduction
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Solution Overview
Problem
In New Radio mobile communications systems, the peak to average power ratio (PAPR) of demodulation reference signal (DMRS) symbols is higher than that of data symbols when transmission precoding is used for physical uplink shared channel (PUSCH) or physical uplink control channel (PUCCH), affecting uplink coverage performance.
Innovation Solution
A method for generating reference signals that involves performing π/2-BPSK or 8-PSK modulation followed by discrete Fourier transform modulation on target-reference-signal sequences, using indication information to indicate the type of reference signal for transmission, thereby reducing PAPR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transmission precoding (DFT-s-OFDM waveform) is used for PUSCH or PUCCH, then spectral efficiency and frequency selectivity are improved, but PAPR of DMRS symbols becomes higher than PAPR of data symbols, degrading uplink coverage performance
Solution Approach 1:
The patent changes the modulation parameter from conventional QPSK to π/2-BPSK or 8-PSK for generating target reference signal sequences. This parameter change in the modulation scheme directly addresses the PAPR issue while maintaining the benefits of transmission precoding, thereby resolving the contradiction between spectral efficiency and uplink coverage performance
2Ease of manufacture
If conventional reference signal generation methods are used, then implementation simplicity is maintained, but PAPR of DMRS symbols is higher, affecting uplink coverage performance
Solution Approach 1:
The patent modifies the modulation parameter (using π/2-BPSK or 8-PSK instead of conventional methods) to reduce PAPR of DMRS symbols. This parameter change maintains implementation simplicity while significantly improving uplink coverage performance by ensuring DMRS PAPR does not exceed data symbol PAPR
Solution Approach 2:
The patent generates target reference signal sequences by applying specific modulation to target reference signal sequences (which can be conventional sequences like Zadoff-Chu or computer-generated sequences). This copying approach with modified modulation maintains the good correlation properties of conventional sequences while achieving lower PAPR
Data Source
AI summary
A method for reference signal generation and a communications device are provided. The method includes: in a case that indication information is received from a second communications device, performing first modulation and then discrete Fourier transform modulation on at least one of target-reference-signal sequences to generate a target reference signal, where the first modulation includes any one of the following: π/2-BPSK modulation and 8-PSK modulation, and the indication information is used to indicate that a first communications device uses the target reference signal for transmission.