MCS Index Selection via Frequency Selectivity Thresholds
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Solution Overview
Problem
Current wireless communication systems lack an efficient method to select modulation and coding scheme (MCS) indices that adapt to varying frequency selectivity, leading to suboptimal performance in different channel environments.
Innovation Solution
A method and apparatus for selecting MCS indices based on frequency selectivity, where a coding rate is adjusted according to whether the measured frequency selectivity is above or below a specified threshold, using a dual MCS table approach with one table for low coding rates and another for high coding rates, to optimize data transmission in wireless communication systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single MCS table is used for all channel conditions, then the system complexity is low, but the transmission performance is suboptimal in varying frequency selectivity environments
Solution Approach 1:
The patent segments the single MCS table into two separate tables: a first MCS table for channels with frequency selectivity above the threshold, and a second MCS table for channels with frequency selectivity below the threshold. This segmentation allows the system to select the appropriate table based on channel conditions, improving transmission performance without requiring a single complex adaptive table for all conditions.
Solution Approach 2:
The patent introduces dynamic selection between two MCS tables based on measured frequency selectivity. The system dynamically switches between the first MCS table (for high frequency selectivity) and the second MCS table (for low frequency selectivity) by comparing the measured frequency selectivity against a threshold, enabling adaptive optimization without continuous table reconstruction.
2Productivity
If the coding rate is fixed regardless of frequency selectivity, then the system operation is simple, but the throughput is not optimized for different channel conditions
Solution Approach 1:
The patent applies local quality by having different coding rates in different MCS tables tailored to specific channel conditions. The first MCS table contains coding rates optimized for high frequency selectivity channels, while the second MCS table contains coding rates optimized for low frequency selectivity channels. This allows the system to apply the appropriate coding rate locally matched to the channel characteristics, maximizing throughput for each condition.
Solution Approach 2:
The patent changes the coding rate parameter based on frequency selectivity measurements. By measuring frequency selectivity and comparing it to a threshold, the system selects from two different MCS tables with different coding rate configurations, thereby adapting the coding rate parameter to match the channel conditions and optimize throughput.
3Reliability
If MCS selection does not consider frequency selectivity, then the measurement and control process is simple, but the frame error rate is high in mismatched conditions
Solution Approach 1:
The patent performs preliminary measurement of frequency selectivity before MCS selection. The system measures the frequency selectivity of the channel and compares it against a threshold to determine which MCS table to use. This preliminary action ensures that the appropriate MCS table is selected before transmission, reducing frame error rates by matching the MCS to channel conditions.
Solution Approach 2:
The patent implements a feedback mechanism where the system measures frequency selectivity, selects the appropriate MCS table based on the measurement, and uses this selected table for transmission. The measurement results feed into the selection decision, creating a closed-loop system that adapts to channel conditions and reduces frame errors through informed MCS selection.
Data Source
AI summary
A method of selecting a modulation and coding scheme (MCS) index in a wireless communication system is disclosed. More specifically, the method includes measuring a frequency selectivity of a receiving channel, selecting a MCS index having a coding rate below a prescribed coding rate threshold value if the measured frequency selectivity is greater than or equal to a specified frequency selectivity threshold, and selecting the MCS index having the coding rate above or equal to the prescribed coding rate threshold value if the measured frequency selectivity is less than the specified frequency selectivity threshold.