DMRS Sequence Grouping for 5G NR pi/2 BPSK Autocorrelation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current DMRS sequence designs for 5G NR networks with pi/2 BPSK modulation, particularly when the DMRS length is less than 30, lack perfect autocorrelation properties due to time-domain modulation, which affects channel estimation accuracy.
Innovation Solution
Implementing predefined DMRS sequence groupings where each subsequent DMRS sequence is determined based on the immediately preceding sequence, using a predefined table to ensure deterministic DMRS sequence hopping and improve autocorrelation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DMRS sequences are designed for 5G NR networks with pi/2 BPSK modulation and length less than 30, then the modulation flexibility and scalability are improved, but the autocorrelation properties deteriorate due to time-domain modulation
Solution Approach 1:
The patent changes the parameter of DMRS sequence design by introducing a specific mathematical structure (conjugate symmetric property where x[n] = x*[N-n]) to maintain perfect autocorrelation. This parameter change allows the sequences to work effectively with pi/2 BPSK modulation while preserving autocorrelation properties, resolving the contradiction between modulation flexibility and reliability
2Adaptability or versatility
If time-domain modulation is applied to DMRS sequences for pi/2 BPSK modulation, then the modulation scheme compatibility is improved, but the channel estimation accuracy deteriorates due to imperfect autocorrelation
Solution Approach 1:
The patent modifies the DMRS sequence parameters to satisfy the conjugate symmetric property, which ensures perfect autocorrelation even under time-domain modulation. This parameter modification enables the sequences to be compatible with pi/2 BPSK modulation while maintaining the autocorrelation properties necessary for accurate channel estimation
Solution Approach 2:
The patent uses base sequences as templates and generates actual DMRS sequences by applying time-domain modulation to these base sequences. The base sequences are designed with specific properties (conjugate symmetry) that are copied and preserved through the modulation process, ensuring that the final modulated sequences maintain perfect autocorrelation for accurate channel estimation
Data Source
AI summary
Wireless communications devices and methods are adapted to facilitate DMRS sequence grouping. In one example, information is obtained for a transmission scheduled with pi/2 BPSK modulation, the transmission including two or more symbols scheduled for a DMRS (DMRS symbols). Respective DMRS sequences may be identified for each of the DMRS symbols, where each DMRS sequence subsequent to another DMRS sequence is dependent on its immediately preceding DMRS sequence, and the transmission may be sent with the identified DMRS sequences in the two or more DMRS symbols. In one example, a first transmission may be sent to schedule a second transmission from another device with pi/2 BPSK modulation, where the second transmission includes two or more DMRS symbols. The scheduled second transmission may be received with at least one DMRS symbol including a DMRS sequence based on its immediately preceding DMRS sequence. Other aspects, embodiments, and features are also included.