Link Adaptation via Mutual Information for Cellular Systems
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Solution Overview
Problem
Existing link adaptation methods in cellular communication networks are computationally inefficient and non-optimal, particularly in complex transmission scenarios due to varying performance of modulations and code rates under different channel conditions.
Innovation Solution
A network node performs link adaptation by receiving channel state information, determining the information carrying capacity over scheduling blocks for various modulation formats, selecting the modulation format with the maximum information carrying capacity, and calculating the transport block size based on signal-to-interference-plus-noise ratio values, using a mutual information method to reduce computational complexity and optimize modulation and coding scheme selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional link adaptation methods are used to determine modulation and coding schemes, then transmission reliability is maintained, but computational complexity increases and link adaptation efficiency decreases
Solution Approach 1:
The patent changes the fundamental parameters used for link adaptation from traditional CQI-based methods to mutual information-based methods. By calculating mutual information between transmitted and received signals, the system directly measures the actual information carrying capacity of the channel, enabling more accurate MCS selection without complex iterative searches through predefined CQI tables.
Solution Approach 2:
The patent replaces the mechanical table-lookup approach with a mathematical information-theoretic approach. Instead of mechanically searching through predefined CQI-MCS mapping tables based on signal quality metrics, the system uses mutual information calculations to directly determine the optimal MCS, substituting a computationally intensive mechanical process with a more efficient mathematical formulation.
2Measurement precision
If existing methods calculate transport block size based on CQI and resource allocation, then compatibility with current standards is maintained, but accuracy in determining information carrying capacity decreases
Solution Approach 1:
The patent introduces mutual information as an intermediary metric between the physical channel characteristics and the transport block size determination. Rather than directly mapping CQI to TBS as in traditional methods, the system uses mutual information calculations as an intermediate step that more accurately reflects the actual information carrying capacity, thereby improving measurement precision while maintaining adaptability.
3Reliability
If the system evaluates multiple modulation formats to find the optimal one, then transmission performance is optimized, but the time and computational resources required increase
Solution Approach 1:
The patent performs preliminary mutual information calculations for multiple modulation formats in advance, before actual transmission decisions are made. By pre-evaluating the information carrying capacity for different modulation schemes based on current channel conditions, the system prepares optimization data ahead of time, reducing the time required for real-time MCS selection while maintaining reliable transmission performance.
Data Source
AI summary
A method and network node for performing link adaption are disclosed. In one embodiment, a channel state information, CSI, measurement is received from a wireless device. An information carrying capacity, ICC, over a number of scheduling blocks, SBs, for a plurality of modulation formats for a target criteria is determined based at least in part on the CSI measurement from the wireless device. A modulation format of the plurality of modulation formats with a maximum ICC is selected. A transport block size, TBS, is determined for the selected modulation format. Link adaptation is performed based on the determined TBS.