Dynamic Sub-Carrier Spacing for Delay Spread Adaptation
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Solution Overview
Problem
Current wireless communication systems face challenges in optimizing transmission link performance due to varying numerologies and environmental factors, particularly in achieving ultra-reliable and low-latency communications, as they struggle to dynamically select the most suitable sub-carrier spacing for different delay spreads and environmental conditions.
Innovation Solution
A method is introduced where communication nodes obtain information on the delay spread of signals to dynamically determine and adjust sub-carrier spacing, optimizing transmission performance by selecting appropriate sub-carrier spacings based on delay spread thresholds and additional parameters like signal quality and phase noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed sub-carrier spacing is used in wireless communication systems, then system complexity is reduced and ease of operation is improved, but transmission link performance deteriorates under varying delay spread conditions and reliability requirements cannot be met
Solution Approach 1:
The patent implements dynamic sub-carrier spacing selection where the system adapts the sub-carrier spacing value based on measured delay spread conditions. The network node determines appropriate sub-carrier spacing from multiple available values according to the detected delay spread, enabling the system to optimize transmission performance for different channel conditions rather than using a fixed spacing value.
Solution Approach 2:
The patent changes the sub-carrier spacing parameter based on delay spread measurements. By selecting from multiple predefined sub-carrier spacing values (e.g., 15 kHz, 30 kHz, 60 kHz, 120 kHz) according to the measured delay spread, the system adjusts this critical parameter to match channel conditions, thereby improving reliability without requiring complete system redesign.
2Adaptability or versatility
If multiple numerologies with different sub-carrier spacings are supported, then adaptability to different delay spreads is improved, but device complexity and difficulty of detecting and measuring increase
Solution Approach 1:
The patent segments the numerology configuration into discrete, predefined sub-carrier spacing values (15 kHz, 30 kHz, 60 kHz, 120 kHz). Rather than allowing continuous or arbitrary spacing values, the system divides the parameter space into specific segments, making it easier to manage and select appropriate values based on delay spread conditions while maintaining adaptability.
Solution Approach 2:
The patent performs preliminary determination of sub-carrier spacing by the network node based on measured delay spread before actual data transmission. The network node detects the delay spread and pre-selects the appropriate sub-carrier spacing value, then configures the user equipment accordingly. This preliminary action simplifies the overall process by centralizing the decision-making and avoiding complex real-time negotiations between nodes.
3Reliability
If sub-carrier spacing is dynamically adjusted based on delay spread, then transmission reliability is improved, but measurement precision requirements increase and difficulty of detecting and measuring delay spread arises
Solution Approach 1:
The patent implements a feedback mechanism where the network node measures delay spread using reference signals (such as SRS - Sounding Reference Signals) transmitted by the user equipment. Based on this measured feedback information, the network node determines the appropriate sub-carrier spacing and configures it for subsequent transmissions. This closed-loop feedback approach enables reliable adaptation without requiring excessively precise measurements, as the system adjusts based on the measured delay spread characteristics.
Data Source
AI summary
A method for improving transmission link performance, performed by a first communication node for wireless communication with a second communication node is provided. The method includes obtaining information of a delay spread of first signals sent between the first communication node and the second communication node and determining at least one of a plurality of different values of a sub-carrier spacing for transmission of second signals between the first communication node and the second communication node, based on the obtained information of the delay spread. The method further includes initiating transmission of the second signals between the first communication node and the second communication node based on the determined at least one value of the sub-carrier spacing.