Uplink Grant CQI Indication for Flexible Feedback
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Solution Overview
Problem
Current CQI reporting mechanisms in LTE systems lack flexibility in resource utilization, making it difficult to support all possible feedback schemes without allocating excessive physical resources, and existing solutions struggle with introducing new feedback schemes that require uplink physical control channel redesigns.
Innovation Solution
A method where the base station determines if channel state feedback is required and selects a suitable type from a predefined set, generating an uplink grant with a transport format that indicates the required amount of feedback information, allowing efficient use of resources and enabling the transmission of high-resolution CQI reports when an uplink grant is available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional CQI reporting mechanisms are used, then resource allocation is simplified, but flexibility in supporting different feedback schemes is limited and excessive physical resources are allocated
Solution Approach 1:
The patent introduces dynamic CQI reporting where the UE adapts its reporting behavior based on whether an uplink grant is available. When an uplink grant is received, the UE transmits high-resolution CQI reports; otherwise, it uses low-resolution reports or skips reporting. This dynamic adaptation allows the system to flexibly support different feedback schemes while allocating physical resources only when necessary, resolving the contradiction between adaptability and resource quantity.
2Measurement precision
If high-resolution CQI reports are always transmitted, then downlink performance is improved, but resource efficiency decreases when uplink grants are not available
Solution Approach 1:
The patent changes the resolution parameter of CQI reports based on uplink grant availability. High-resolution reports (more bits) are transmitted only when uplink grants are available, while low-resolution reports (fewer bits) or no reports are used when grants are not available. This parameter adaptation maintains measurement precision when resources permit while avoiding energy waste when resources are constrained, resolving the contradiction between precision and energy loss.
3Loss of information
If the UE always transmits CQI reports, then the base station has continuous channel state information, but the uplink resource requirements increase
Solution Approach 1:
The patent implements periodic CQI reporting triggered by uplink grant reception rather than continuous reporting. The UE transmits CQI reports periodically whenever it receives an uplink grant, ensuring the base station receives channel state information at regular intervals when resources are available, while avoiding constant transmissions that would consume excessive uplink resources. This periodic action based on grant availability resolves the contradiction between information availability and resource quantity.
Data Source
AI summary
The present invention relates to a method, user equipment and a base station adapted to handle channel state feed-back reports in a more flexible way. More specifically, a channel state feedback procedure is provided which utilizes the resources available for transmission of channel state feedback more efficiently. This is achieved by including uplink grant availability into the channel state feedback reporting triggers used for determining when and how to send channel state feedback from a UE, i.e. a channel state feedback reporting request may be sent by a base station in an uplink grant to a UE comprising an indication of an expected amount of information to be returned.