NR DM-RS Sequence Generation Using Nested PN Sequences
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Solution Overview
Problem
The existing 5G New Radio (NR) systems face challenges in efficiently generating and mapping reference signals (RS) and assigning precoders due to varying user equipment (UE) bandwidth assumptions, which affect channel state information determination and overall performance.
Innovation Solution
The proposed solution involves techniques for DM-RS sequence generation and precoder assignment that are independent of UE bandwidth assumptions, using nested PN sequences for RS modulation and cell/UE-specific PRG assignment to improve CSI determination and performance across different bandwidth scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RS sequence generation methods are used, then the system can operate with standard procedures, but the channel state information determination becomes inaccurate when UE bandwidth assumptions vary
Solution Approach 1:
The patent applies nesting by generating a basic PN sequence and then generating extended sequences that contain the basic sequence as a subset. The extended PN sequences are constructed by repeating and interleaving the basic sequence with modified versions, creating a nested structure where longer sequences are built from shorter ones. This ensures that channel state information determination remains accurate across different bandwidth configurations because the extended sequences maintain the fundamental properties of the basic sequence while adapting to larger bandwidths.
Solution Approach 2:
The patent creates a universal RS sequence generation method that works across multiple bandwidth scenarios. By designing extended PN sequences that can be generated from a single basic sequence through systematic repetition and interleaving, the system achieves multi-functionality where the same generation algorithm serves both narrowband and wideband configurations. This universal approach eliminates the need for separate sequence generation methods for different bandwidth assumptions, thereby improving both measurement precision and adaptability.
2Measurement precision
If separate PN sequences are generated for each bandwidth scenario, then accuracy for each specific bandwidth can be optimized, but the system complexity increases
Solution Approach 1:
The patent reduces complexity by nesting sequence generation within a unified framework. Instead of maintaining separate generation algorithms for each bandwidth, the system generates a single basic PN sequence and then creates extended sequences by repeating and interleaving this basic sequence. This nested approach allows the system to achieve bandwidth-specific optimization while using a single generation algorithm, thereby reducing device complexity while maintaining measurement precision across different bandwidth scenarios.
Solution Approach 2:
The patent implements a universal sequence generation algorithm that serves multiple bandwidth scenarios simultaneously. The same basic generation procedure produces sequences suitable for both narrowband and wideband configurations through parameter adjustments in the repetition and interleaving processes. This multi-functional approach eliminates the need for multiple separate generation algorithms, significantly reducing system complexity while preserving accuracy for each specific bandwidth case.
3Ease of manufacture
If LTE-based mapping is used for RS, then compatibility with existing systems is maintained, but the mapping does not optimize for NR-specific bandwidth configurations
Solution Approach 1:
The patent introduces dynamic adaptability to the RS mapping process by making the sequence generation and mapping behavior dependent on the actual bandwidth configuration. The system dynamically adjusts the PN sequence length and mapping pattern based on whether the configuration is narrowband or wideband, rather than using a fixed LTE-based mapping approach. This dynamic behavior allows the system to maintain LTE compatibility for basic operations while optimizing performance for NR-specific bandwidth configurations through adaptive sequence selection and mapping.
Solution Approach 2:
The patent optimizes NR-specific performance by changing key parameters of the RS sequence generation and mapping based on bandwidth configuration. The system modifies parameters such as the PN sequence length, repetition factor, and interleaving pattern according to the actual bandwidth assumptions. These parameter changes enable the system to maintain compatibility with LTE-based procedures when appropriate while achieving superior optimization for NR-specific bandwidth scenarios, thereby resolving the contradiction between compatibility and adaptability.
Data Source
AI summary
Systems, methods, and circuitries are disclosed for generating demodulation reference signals (DM-RS). In one example, a method for a user equipment (UE), includes receiving a configuration of a plurality of bandwidth parts (BWPs) configured with respective numerologies; generating a first pseudo-random sequence based at least in part on one or more of a physical cell ID, a virtual cell ID, a symbol index, a slot index, a frame index, a scrambling ID, or a UE ID for generation of a first DM-RS sequence, wherein a initialization seed for the first pseudo-random sequence is based on a scrambling ID and a slot index, wherein, for the plurality of BWPs a respective scrambling ID is associated with each BWP, and wherein the slot index is defined in accordance with the numerology of the associated BWP; and mapping, for a first BWP, the first DM-RS sequence to at least one DM-RS symbol.