User Terminal CSI Feedback Priority Selection
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Solution Overview
Problem
In LTE-A systems, coordinating multi-point transmission/reception techniques face challenges in accurately determining and feeding back channel state information (CSI) from user terminals due to interference and resource constraints, particularly when multiple pieces of CSI collide during uplink transmission.
Innovation Solution
A user terminal is configured to generate CSI using channel state measurement reference signals from multiple radio base stations, with a selection mechanism that prioritizes and selectively feeds back CSI based on resource indices and interference estimation resources to prevent collisions, ensuring effective CSI feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pieces of channel state information are fed back simultaneously via uplink control channel, then comprehensive channel state measurement is improved, but collision between multiple pieces of channel state information occurs
Solution Approach 1:
The patent segments multiple pieces of channel state information into different priority levels (first priority and second priority). The user terminal selectively feeds back only the first priority channel state information when resources are limited, preventing collisions while maintaining essential feedback functionality. This segmentation by priority resolves the contradiction between comprehensive measurement and reliable feedback.
2Reliability
If channel state information is selectively fed back based on priority, then collision between multiple pieces of information is reduced, but feedback completeness may be compromised
Solution Approach 1:
The patent applies local quality by assigning different priorities to different pieces of channel state information based on their specific characteristics and importance. First priority information (such as CSI for serving cells) is fed back reliably, while second priority information (such as CSI for non-serving cells) is selectively dropped. This differentiated approach maintains feedback reliability for critical information while managing overall information loss.
3Productivity
If coordinated multi-point transmission/reception is implemented with multiple radio base stations, then system performance and throughput are improved, but interference between transmission points increases
Solution Approach 1:
The patent implements feedback mechanisms where user terminals measure channel state information from multiple radio base stations and selectively feed back this information to the serving base station. The feedback includes channel quality indicators and interference measurements that enable the network to adjust transmission parameters, manage interference between coordinated transmission points, and optimize system throughput. This feedback loop resolves the contradiction by providing the necessary information to manage interference while maintaining coordinated transmission benefits.
Data Source
AI summary
To make it possible to feed back channel state information adequately even when a plurality of pieces of channel state information are generated in a user terminal, a user terminal that is configured to be able to conduct coordinated multi-point transmission/reception with a plurality of radio base stations has a generating section that generates a plurality of kinds of channel state information using channel state measurement reference signals transmitted from each radio base station, a selection section that selects predetermined channel state information to feed back, from the plurality of kinds of channel state information, and a transmission section that feeds back the predetermined channel state information to the radio base station via an uplink control channel, and the selection section selects the predetermined channel state information based at least on the priorities assigned to the resource indices of channel state measurement reference signals corresponding to each channel state information.