Downlink Control Information Format for Carrier Aggregation Scheduling
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Solution Overview
Problem
In conventional mobile communication systems, it is challenging to specify which downlink frequency bands generate channel state information when multiple component carriers are used, leading to inefficient radio resource scheduling due to unclear channel state information generation objects.
Innovation Solution
The system includes a mechanism where the base station apparatus transmits a downlink control information format with an information bit indicating which downlink component carriers require channel state information reporting, allowing the mobile station apparatus to report channel state information accordingly, with the correspondence between the information bit and component carriers set using higher-layer signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple downlink component carriers are used for frequency band aggregation, then the frequency bandwidth and data transmission speed are improved, but it becomes difficult to specify which component carriers generate channel state information, leading to scheduling inefficiency
Solution Approach 1:
The patent segments the downlink component carriers by introducing a specific information bit in downlink control information that individually identifies which component carrier(s) the mobile station should use for channel state information generation. This segmentation allows the base station to selectively assign channel state information generation tasks to specific component carriers among multiple aggregated carriers, resolving the scheduling inefficiency while maintaining the bandwidth benefits of carrier aggregation.
2Loss of information
If channel state information is generated for all downlink component carriers, then complete channel knowledge is achieved, but the signaling overhead and processing complexity increase
Solution Approach 1:
The patent extracts only the necessary channel state information by allowing the mobile station to generate CSI for a selected subset of downlink component carriers rather than all carriers. The base station controls this selection through the information bit in downlink control information, enabling extraction of essential channel knowledge while minimizing signaling overhead and processing complexity associated with full-carrier CSI reporting.
3Adaptability or versatility
If the mobile station apparatus autonomously determines channel state information generation, then reporting flexibility is improved, but coordination with base station scheduling deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the base station sends downlink control information containing an information bit that specifies which component carrier(s) the mobile station should use for CSI generation. The mobile station reports CSI based on this indication, creating a closed-loop feedback system that maintains both reporting flexibility and reliable coordination with base station scheduling decisions.
Data Source
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AI summary
To specify flexibly one or more downlink component carriers for which a mobile station apparatus generates channel state information when performing communication using a plurality of component carriers complexly. A base station apparatus transmits to the mobile station apparatus a downlink control information format in which an information bit set to a value corresponding to one or more downlink component carriers requesting to report channel state information is included, and which is used for scheduling of a physical uplink shared channel, and the mobile station apparatus reports the channel state information for the one or more downlink component carriers to the base station apparatus using the physical uplink shared channel in accordance with the value set to the information bit, and a correspondence between a value set to the information bit and the one or more downlink component carriers is set in the mobile station apparatus by the base station apparatus using a signal of a higher layer.