Wireless Communication Apparatus Adaptive Modulation Control
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Solution Overview
Problem
Closed-loop link adaptation schemes in wireless communication systems face challenges due to unreliable feedback results caused by varying channel states, leading to suboptimal MCS control and deterioration in communication quality or throughput, especially in environments with multiple terminals where feedback timing is uncertain.
Innovation Solution
A wireless communication apparatus that includes a transmitter, receiver, estimation unit for channel variation, and control unit to determine modulation and error correction coding schemes based on response time thresholds, ensuring reliable feedback information is used only when received within a predetermined time frame, thereby adapting to channel variations effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback request frames are transmitted periodically to enable closed-loop link adaptation control, then MCS selection accuracy is improved, but unnecessary traffic increases and system throughput deteriorates
Solution Approach 1:
The patent implements periodic feedback request transmission at predetermined intervals rather than continuously or on-demand. This periodic action ensures MCS selection accuracy is maintained through regular channel state updates while avoiding excessive feedback traffic that would degrade system throughput. The predetermined interval balances the need for accurate MCS selection with the need to minimize overhead traffic.
2Adaptability or versatility
If feedback requests are transmitted frequently to track varying wireless propagation state, then adaptability of MCS control is improved, but unnecessary traffic increases and throughput deteriorates
Solution Approach 1:
The patent uses periodic feedback requests at predetermined intervals to maintain MCS control adaptability to varying wireless propagation conditions. This periodic approach provides sufficient channel state updates to track propagation state changes while avoiding excessive requests that would generate unnecessary traffic and reduce throughput. The predetermined interval is optimized to balance adaptability with throughput preservation.
3Productivity
If feedback requests are transmitted less frequently to reduce traffic, then system throughput is improved, but ability to adaptively perform MCS control deteriorates
Solution Approach 1:
The patent implements periodic feedback request transmission at predetermined intervals that are optimized to maintain sufficient MCS control adaptability while minimizing overhead traffic. This periodic action ensures that feedback requests are transmitted frequently enough to track channel state variations for adaptive MCS selection, but not so frequently as to generate excessive traffic that would degrade system throughput.
4Extent of automation
If feedback results are used despite uncertain timing in wireless LAN environment, then closed-loop link adaptation control is enabled, but reliability of feedback information deteriorates
Solution Approach 1:
The patent implements closed-loop link adaptation control by transmitting feedback request frames and using the received feedback results for MCS selection. The system automatically processes the feedback information to adjust transmission parameters, enabling automated closed-loop control despite the uncertain timing characteristics of wireless LAN environments. This feedback mechanism allows the transmitter to adaptively adjust MCS based on receiver conditions while maintaining operational automation.
Data Source
AI summary
A wireless communication apparatus includes a transmitter and a receiver, and determines a modulation and error correction coding scheme used by the transmitter. The apparatus estimates a degree of channel variation, transmits, by the transmitter, a first frame for requesting response information necessary to select the modulation and error correction coding scheme, measures a response time between a instant when the transmitter transmits the first frame and a instant when the receiver receives a second frame including the response information, determines a threshold value of the response time for determining reliability of the response information, based on the degree of channel variation, and determines the modulation and error correction coding scheme selected based on the response information included in the second frame received by the receiver in the response time shorter than the threshold value.