CG Sequence Selection for Low PAPR DMRS Transmission
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Solution Overview
Problem
The detailed Computer Generated (CG) sequences for generating Demodulation Reference Signal (DMRS) sequences in New Radio (NR) access, particularly for π/2-BPSK modulated Physical Uplink Shared Channel (PUSCH) and Physical Uplink Control Channel (PUCCH), have not been specified, leading to inefficiencies in DMRS transmission.
Innovation Solution
A method for selecting and generating CG sequences for DMRS transmission, ensuring low Peak to Average Power Ratio (PAPR), good autocorrelation, and cross-correlation performance, by configuring CG sequence tables in terminal and network devices, which include specific sequences for sequence lengths of 6, 12, 18, and 24, and determining the appropriate sequences based on predetermined criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DMRS sequence generation is based on unspecified CG sequences, then implementation flexibility is maintained, but transmission reliability and performance are degraded
Solution Approach 1:
The patent applies preliminary action by pre-configuring CG sequence tables in both terminal and network devices before actual DMRS transmission occurs. The sequence tables are prepared in advance with specific CG sequences for different sequence lengths (6, 12, 18, 24), allowing devices to quickly select appropriate sequences without real-time computation, thereby improving transmission reliability while maintaining implementation feasibility
Solution Approach 2:
The patent applies parameter changes by establishing specific parameters for CG sequences including sequence length parameters (6, 12, 18, 24), PAPR thresholds, and autocorrelation/cross-correlation performance criteria. These parameter specifications transform the undefined CG sequences into well-defined mathematical structures with controllable properties, improving DMRS transmission reliability through standardized parameter control
2Reliability
If CG sequences are not properly optimized, then implementation is simpler, but PAPR and correlation performance deteriorate
Solution Approach 1:
The patent pre-generates and stores optimized CG sequences in sequence tables during device initialization or manufacturing phase. This preliminary action separates the complex sequence generation process from real-time transmission, allowing sophisticated sequence optimization (for PAPR and correlation performance) to be performed in advance without impacting transmission efficiency during operation
Solution Approach 2:
The patent uses copying by storing pre-computed CG sequences in lookup tables that can be quickly referenced and copied during DMRS transmission. Instead of generating sequences in real-time, the system copies appropriate sequences from pre-prepared tables, maintaining both transmission efficiency and sequence optimization without requiring complex real-time generation capabilities
Data Source
AI summary
Embodiments of the present disclosure relate to methods, devices and computer readable media for DMRS transmission. A method implemented at a terminal device comprises selecting, from a plurality of computer generated (CG) sequences, a CG sequence for an uplink channel modulated with a predetermined modulation technique. The method further comprises generating, based on the selected CG sequence, a DMRS sequence for the uplink channel. In addition, the method further comprises transmitting, over the uplink channel, the DMRS sequence to a network device. The embodiments of the present disclosure can provide a set of candidate CG sequences with low PAPR, good autocorrelation performance and good cross-correlation performance for generating DMRS sequences for π/2-BPSK modulated PUSCH or PUCCH.