Terminal Device Adaptive CSI Transmission for LTE Efficiency
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Solution Overview
Problem
In wireless communication systems, particularly in LTE, there is a lack of a concrete method for efficiently transmitting channel state information (CSI) in the downlink.
Innovation Solution
The solution involves a terminal apparatus and a base station apparatus equipped with channel measurement units and transmitters/receivers that determine CSI content based on the type of downlink physical channel allocated to or closest to a CSI reference resource, enabling efficient CSI transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CSI transmission method is not adequately defined, then system flexibility is maintained, but communication efficiency deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting CSI content based on the type of downlink physical channel (PDSCH or sPDSCH) allocated to the CSI reference resource. When sPDSCH is detected, the terminal transmits only CQI information; when PDSCH is detected, the terminal transmits CQI, PMI, and RI information. This parameter-based adaptation resolves the contradiction by optimizing communication efficiency for different channel types without requiring complex separate transmission mechanisms.
2Productivity
If CSI content is fixed for all downlink channels, then device complexity is reduced, but communication efficiency deteriorates
Solution Approach 1:
The patent implements dynamics by making CSI transmission content adaptive rather than fixed. The terminal device dynamically determines the CSI content based on real-time detection of the downlink physical channel type allocated to the CSI reference resource. This dynamic adjustment mechanism allows the system to optimize communication efficiency for different channel characteristics while maintaining manageable device complexity through a unified decision-making framework.
3Productivity
If different CSI transmission methods are used for different downlink channels, then communication efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by tailoring the CSI transmission content to the specific characteristics of each downlink physical channel type. For sPDSCH (short TTI), only CQI is transmitted due to its time-sensitive nature. For PDSCH (normal TTI), full CSI including CQI, PMI, and RI is transmitted. This localized optimization approach improves transmission efficiency for each channel type while keeping the overall mechanism simple through clear channel-type-based differentiation.
Data Source
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AI summary
The terminal apparatus derives CSI, transmits the CSI, and determines content of the CSI based on a type of a downlink physical channel that is allocated to a CSI reference resource or allocated before and closest to the CSI reference resource.