5G NR PBCH DMRS Cyclic Shift Distribution
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Solution Overview
Problem
In 5G new radio (NR) technology, the detection performance of the physical broadcast channel (PBCH) demodulation reference signal (DMRS) is affected by unevenly distributed cyclic shift values of the m-sequence, leading to deteriorated detection performance due to small intervals between cyclic shift values for the same physical cell identifier and timing information.
Innovation Solution
A signal processing method that generates a gold sequence reference signal based on first and second m-sequences, where the cyclic shift values are determined to ensure even distribution for the same physical cell identifier, carrying physical cell identifier and synchronization signal block time index information, thereby improving the detection performance of the PBCH DMRS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cyclic shift values are used for reference signal sequence generation, then the reference signal can be generated based on physical cell identifier and timing information, but the cyclic shift values are unevenly distributed causing small intervals between values for the same physical cell identifier and timing information, which deteriorates detection performance
Solution Approach 1:
The patent changes the parameter used for cyclic shift determination from directly using physical cell identifier and timing information to using a derived parameter (floor of physical cell identifier divided by 6). This parameter transformation ensures more uniform distribution of cyclic shift values across different cells, resolving the issue of small intervals between cyclic shift values for the same physical cell identifier and timing information, thereby improving detection performance while maintaining the ease of reference signal generation.
2Productivity
If cyclic shift values are determined by physical cell identifier and timing information, then the reference signal sequence can be generated, but the intervals between cyclic shift values are small leading to deteriorated detection performance
Solution Approach 1:
The patent transforms the parameter determination method by introducing a floor division operation (physical cell identifier / 6) to determine the cyclic shift value. This parameter change maintains computational efficiency for reference signal generation while ensuring that cyclic shift values are more evenly distributed, thereby improving detection performance without sacrificing generation efficiency.
Solution Approach 2:
The patent performs preliminary grouping of physical cell identifiers by using the floor division operation to determine cyclic shift values before actual reference signal generation. This preliminary action ensures that cells are pre-assigned to different cyclic shift groups, preventing small intervals between cyclic shift values and improving detection performance in advance of the actual signal detection process.
Data Source
Figure 1~2B
Figure 3A
Figure 3B~4
AI summary
This application discloses a signal processing method and apparatus, to design a reference signal. The method includes: generating a reference signal sequence based on a first m-sequence and a second m-sequence, where the reference signal sequence is a gold sequence, a cyclic shift value of the first m-sequence is determined based on a physical cell identifier and first timing information, and for a same physical cell identifier, a difference between two cyclic shift values of the first m-sequence that are separately determined based on the physical cell identifier and any two pieces of adjacent first timing information is L1, where L1 is a positive integer, and the first timing information includes a synchronization signal block time index or a first part of the synchronization signal block time index; and after modulating the generated reference signal sequence, mapping a modulated reference signal sequence to N subcarriers to obtain a reference signal, where N is a positive integer greater than or equal to 1.