PUCCH Format Switching for CSI Collision Management
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Solution Overview
Problem
In LTE wireless communication systems, efficient resource allocation for channel state information (CSI) transmission is hindered due to collisions in subframes, leading to reduced scheduling efficiency of physical downlink shared channels (PDSCH).
Innovation Solution
A mobile station device and base station device configure resources for physical uplink control channels (PUCCH) in multiple formats to enable efficient transmission of CSI, using a first format for single reports and a second format for multiple reports, allowing for prioritization and transmission of colliding reports using a secondary format.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If periodic channel state information reports for multiple cells are transmitted using a single PUCCH format, then device complexity is reduced, but collision of multiple reports in the same subframe causes loss of information and reduced scheduling efficiency
Solution Approach 1:
The patent segments the PUCCH resources into multiple formats (first format for single report, second format for multiple reports). When multiple CSI reports collide in the same subframe, the system switches to the second PUCCH format which is designed to handle multiple reports simultaneously, thereby preventing information loss while maintaining manageable device complexity through standardized format switching procedures
Solution Approach 2:
The patent implements dynamic switching between different PUCCH formats based on the number of CSI reports that need to be transmitted in each subframe. The system adapts the PUCCH format selection according to the collision status of CSI reports, enabling flexible resource allocation that optimizes information transmission while controlling device complexity through conditional format selection
2Reliability
If multiple PUCCH formats are configured for different cells, then channel state information transmission reliability is improved, but device complexity and resource allocation complexity increase
Solution Approach 1:
The patent creates a universal resource configuration where a second PUCCH format is configured to handle multiple CSI reports from different cells. This multi-functional resource can accommodate various combinations of colliding reports, improving transmission reliability while controlling device complexity through a standardized multi-report handling mechanism rather than requiring unique configurations for each possible collision scenario
Solution Approach 2:
The patent performs preliminary configuration of multiple PUCCH formats and their corresponding resources before CSI report collisions occur. The base station pre-configures the mobile station with both first and second PUCCH formats, establishing the resource allocation framework in advance. This preliminary action enables reliable CSI transmission during collisions without requiring complex real-time decision-making, thereby improving reliability while keeping device complexity manageable through pre-established protocols
3Ease of operation
If a single PUCCH format is used for all cells, then resource allocation is simplified, but scheduling efficiency of PDSCH deteriorates due to dropped CSI reports
Solution Approach 1:
The patent implements dynamic resource allocation that adapts to the number of CSI reports requiring transmission. When only one CSI report needs to be transmitted, the system uses the simpler first PUCCH format. When multiple reports collide, the system dynamically switches to the second PUCCH format capable of handling multiple reports. This dynamic approach maintains ease of operation through standardized format selection while improving scheduling efficiency by preventing CSI report drops
Solution Approach 2:
The patent changes the PUCCH format parameter based on the number of CSI reports that need to be transmitted in each subframe. By adjusting this key parameter dynamically, the system achieves efficient resource allocation that adapts to varying traffic conditions, thereby maintaining ease of operation while significantly improving scheduling efficiency through appropriate format selection that prevents information loss
Data Source
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AI summary
If a plurality of channel state information reports corresponding to different cells have collided (Yes in step S2408), a mobile station device 1 selects two channel state information reports in accordance with priorities of report types and cell indices of cells, and drops the other channel state information reports (step S2412). The mobile station device 1 transmits the selected two channel state information reports using a resource for PUCCH format 3, which is used in case of collision of a plurality of channel state information reports corresponding to different cells (step S2414).