Reference Signal Location in DFT-s-OFDM Symbols
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Solution Overview
Problem
High-frequency communication systems face performance deterioration due to phase noise, center frequency offset, and Doppler frequency shift, which are exacerbated by insufficient cyclic prefixes in high subcarrier spacing, leading to conflicts between phase tracking reference signals and data blocks in DFT-s-OFDM waveforms with flexible guard intervals, affecting demodulation performance.
Innovation Solution
A method for determining the target location of a reference signal in a DFT-s-OFDM symbol based on both pattern and location parameters, ensuring proper distribution and reducing conflicts with data blocks, thereby improving phase noise estimation and channel estimation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high subcarrier spacing is used to resist phase noise, then phase noise compensation performance is improved, but cyclic prefix becomes insufficient leading to performance deterioration
Solution Approach 1:
The patent changes the parameter of subcarrier spacing to a flexible guard interval spread mechanism. Instead of using fixed high SCS, the system dynamically adjusts guard intervals based on channel conditions, allowing the system to adapt to varying phase noise levels while maintaining sufficient cyclic prefix length for large delay spread scenarios.
2Reliability
If cyclic prefix length is increased to handle large delay spread, then performance is improved, but network efficiency deteriorates
Solution Approach 1:
The patent introduces a dynamic guard interval spread mechanism where the cyclic prefix length is not fixed but can be adjusted based on channel conditions. The system dynamically determines the appropriate guard interval length to handle large delay spread while avoiding excessive lengths that would reduce network efficiency, thus achieving adaptability between reliability and productivity.
3Ease of manufacture
If reference signal is placed at fixed location in DFT-s-OFDM symbol, then implementation is simplified, but conflict with data block occurs reducing estimation accuracy
Solution Approach 1:
The patent transitions from fixed reference signal placement to a dynamic location determination mechanism. The reference signal location is now determined based on both pattern parameters and location parameters of data blocks, allowing the system to adaptively position the reference signal to avoid conflicts with data blocks while maintaining implementation simplicity through automated location calculation.
Solution Approach 2:
The patent applies different location strategies for reference signals in different regions of the DFT-s-OFDM symbol. By considering the location parameters of data blocks, the system determines optimal reference signal positions in specific regions, ensuring that reference signals are placed where they provide best estimation accuracy without conflicting with data blocks, thus achieving local optimization of measurement precision.
Data Source
AI summary
A signal transmission method and a communication apparatus are described. The method may include: mapping a reference signal to a target location in a discrete Fourier transform-spread-orthogonal frequency division multiplexing DFT-s-OFDM symbol, where the target location is determined based on a pattern parameter of the reference signal and a location parameter of a data block, and the location parameter of the data block is used to determine a location of the data block in the DFT-s-OFDM symbol; and sending the DFT-s-OFDM symbol. Not only the pattern parameter of the reference signal is considered, but also the location parameter of the data block is considered, so that overall location distribution of the reference signal can be more proper, phase noise estimation performance and channel estimation performance are improved, and demodulation performance is improved.