Demodulation Reference Signal Density Tuning for Channel Estimation
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Solution Overview
Problem
In wireless communication systems, particularly in scenarios like non-terrestrial networks and terrestrial high frequencies, the existing demodulation reference signals (DMRS) with dense frequency domain and sparse time domain resources lead to resource waste due to weak frequency selective characteristics, affecting channel estimation and receiving performance.
Innovation Solution
Adopting a DMRS transmission method that adjusts the time-frequency resources by setting the frequency domain density of the first-type DMRS to 1/N of the second-type DMRS and the symbol occupancy to M times that of the second-type DMRS, where N and M are integers, allowing for more efficient resource use and improved channel estimation precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dense comb structure is used in frequency domain for DMRS transmission, then channel estimation precision for frequency-selective fading is improved, but resource waste occurs in scenarios with weak frequency selective characteristics
Solution Approach 1:
The patent applies dynamics by making the DMRS time-frequency resource configuration adaptive rather than fixed. The network device dynamically selects between first-type and second-type DMRS based on channel conditions (frequency selective fading strength), allowing the system to optimize resource usage according to actual channel characteristics. This resolves the contradiction by enabling the system to use dense frequency resources only when needed for channel estimation precision while avoiding resource waste in scenarios with weak frequency selectivity.
Solution Approach 2:
The patent changes the parameters of DMRS configuration by introducing two distinct types with different frequency domain densities (1/N for first-type, 1 for second-type). The network device adjusts these parameters based on channel conditions, switching between configurations to balance channel estimation precision and resource efficiency. This parameter adaptation resolves the technical contradiction by matching resource density to actual channel requirements.
2Measurement precision
If frequency domain density of DMRS is increased, then channel estimation accuracy is improved, but throughput is reduced due to more resource occupation
Solution Approach 1:
The system dynamically adjusts DMRS frequency domain density based on channel conditions. In scenarios with strong frequency selective fading, the second-type DMRS with higher frequency domain density is used to improve channel estimation accuracy. In scenarios with weak frequency selectivity, the first-type DMRS with lower frequency domain density (1/N) is used to reduce resource occupation and increase throughput. This dynamic adaptation resolves the contradiction between channel estimation accuracy and throughput.
Solution Approach 2:
The patent introduces configurable frequency domain density parameters (1/N for first-type, 1 for second-type) that can be adjusted based on channel characteristics. By changing these parameters adaptively, the system optimizes the balance between channel estimation accuracy and resource efficiency, thereby resolving the contradiction with throughput performance.
3Measurement precision
If time domain symbols for DMRS are increased, then channel estimation precision is improved, but resource occupation increases
Solution Approach 1:
The network device dynamically selects between first-type and second-type DMRS configurations based on channel conditions. The first-type DMRS uses M times the quantity of symbols of the second-type, allowing increased time domain resource occupation only when channel estimation precision is critically needed. This dynamic selection resolves the contradiction by adapting resource occupation to actual channel requirements.
Solution Approach 2:
The patent introduces a configurable parameter M that determines the quantity of symbols for first-type DMRS relative to second-type DMRS. This parameter can be adjusted to balance channel estimation precision against resource occupation, resolving the technical contradiction by allowing flexible parameter optimization based on service requirements and channel conditions.
Data Source
AI summary
This application provides a demodulation reference signal transmission method which includes a communication apparatus determining a first time-frequency resource that is in at least one resource block (RB) and that is for transmission of a first-type demodulation reference signal (DMRS), frequency domain density of the first-type DMRS is 1/N of that of a second-type DMRS, a quantity of symbols occupied by the first-type DMRS in the at least one RB is M times those occupied by the second-type DMRS in the at least one RB, and a time-frequency resource for transmission of the second-type DMRS is determined in a predefined configuration manner, where N is an integer greater than 1, and M is an integer greater than 0. The communication apparatus sends or receives a first DMRS based on the first time-frequency resource, where the first DMRS belongs to the first-type DMRS.