MIMO Link Control via Segmented Parameter Selection
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Solution Overview
Problem
In MIMO wireless communication systems, the limited uplink feedback capacity restricts the number of possible modulation and coding schemes (MCS) that can be used, leading to suboptimal throughput and robustness due to the fixed set of MCS combinations, which may not include all potentially useful configurations.
Innovation Solution
A method that determines the quality of the communications link and selects a group of transmission parameters and a specific parameter from that group, using identification labels to communicate the chosen configuration, allowing all possible transmission parameters to be used while minimizing feedback data, and enabling more timely and robust link control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a limited set of MCS combinations is used to reduce feedback bits, then feedback overhead is reduced, but the system cannot utilize all potentially useful transmission configurations
Solution Approach 1:
The patent segments the MCS selection process into two independent parts: group selection (determining which set of parameters to use) and parameter selection (determining which specific parameter within the group). This segmentation allows the system to efficiently convey selection information through feedback bits while maintaining access to a comprehensive set of possible configurations, as the group index and parameter index can be independently optimized.
Solution Approach 2:
The patent implements a nested structure where parameters are organized into groups, and each group contains multiple parameters. The feedback mechanism nests two levels of selection: first selecting a group based on channel conditions, then selecting a specific parameter within that group. This nested organization allows compact representation of the selection space while preserving fine-grained control over transmission parameters.
2Adaptability or versatility
If more MCS combinations are made available, then system adaptability improves, but the number of feedback bits required increases
Solution Approach 1:
By segmenting the MCS space into groups and parameters, the system can manage a large total number of configurations without requiring proportionally large feedback bits. The group selection and parameter selection can be handled separately with optimized bit allocation, reducing the total feedback overhead compared to a flat enumeration of all possible MCS combinations.
Solution Approach 2:
The patent applies local quality by allowing different levels of selection precision for different aspects of MCS configuration. The group selection can use coarser granularity based on overall channel conditions, while parameter selection within the group can use finer granularity for specific transmission characteristics. This localized optimization reduces total feedback requirements while maintaining adaptability.
Data Source
AI summary
The present invention is directed to a method of controlling a communications link and apparatus configured to perform this method. This invention is particularly related to but in no way limited to MIMO (multiple inputs multiple outputs) wireless communications systems. The method comprises the steps of determining at the receiver the quality of the communications link and based on this, selecting a group of transmission parameters and an element from this group. These selections are then communicated to the transmitter. The transmission parameter may be the transmission configuration such as the modulation and coding scheme. The invention minimizes the required feedback signalling from the receiver to the transmitter by exploiting temporal correlation of the parameter being controlled, while allowing rapid selection of the parameter.