D2D Channel State Feedback for Base Station Scheduling
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Solution Overview
Problem
In Device to Device Proximity Service (D2D ProSe) scenarios, base stations cannot learn the channel quality between user devices, hindering effective resource scheduling for direct communication.
Innovation Solution
User devices send channel state information to a third device in a separate subframe, allowing the third device to perform resource scheduling for direct communication between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If user devices perform direct communication without base station participation, then communication efficiency is improved, but the base station cannot learn channel quality between user devices
Solution Approach 1:
The patent introduces a third device (base station or access point) as an intermediary to collect channel state information from user devices performing direct communication. This mediator receives CSI reports from the communicating devices and uses this information for resource scheduling, thereby resolving the information asymmetry problem while maintaining direct communication efficiency.
Solution Approach 2:
The patent implements a feedback mechanism where user devices send channel state information (CSI) reports to the third device. This feedback loop enables the third device to learn about channel conditions between user devices without directly participating in their communication, thus maintaining productivity while eliminating information loss.
2Ease of operation
If base station sends resource allocation signaling to user devices, then resource scheduling is improved, but the base station cannot obtain direct link channel quality information
Solution Approach 1:
The patent establishes a feedback mechanism where user devices transmit channel state information (CSI) reports containing direct link channel quality to the base station. This enables the base station to obtain accurate channel quality information for resource scheduling decisions while maintaining its scheduling control capability.
Solution Approach 2:
The patent implements preliminary measurement and reporting actions where user devices measure channel state information and send CSI reports to the base station before resource allocation decisions are made. This preliminary information gathering enables the base station to perform informed resource scheduling without directly participating in the direct communication link.
3Measurement precision
If user devices send channel state information to third device in separate subframe, then resource scheduling accuracy is improved, but communication overhead increases
Solution Approach 1:
The patent segments the communication process into distinct phases: direct communication in one subframe and CSI reporting in another subframe. This temporal segmentation allows accurate channel state information collection without interfering with the primary communication function, managing overhead by separating measurement and data transmission.
Solution Approach 2:
The patent implements periodic CSI reporting where user devices send channel state information at specific intervals (separate subframes) rather than continuously. This periodic action maintains measurement precision for resource scheduling while controlling communication overhead by transmitting information only when necessary for scheduling decisions.
Data Source
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AI summary
Embodiments of the present invention provide an information sending method and apparatus, where direct communication is performed between user devices in a first subframe, and channel state information of direct communication performed between the user devices is sent to a third device in a second subframe, so that the third device can learn the channel state information between the user devices, and further perform resource scheduling for the user devices performing direct communication.