CSI-RS Resource Pattern Allocation for Wireless Interference
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Solution Overview
Problem
The introduction of new channel state information reference signals (CSI-RS) in wireless communication systems poses challenges related to available transmission bandwidth, coexistence with legacy systems, and backward compatibility with user equipment not designed to operate with these new signals, particularly in LTE systems with higher antenna configurations.
Innovation Solution
A method and apparatus for selecting a cell-specific CSI-RS resource pattern that is non-colocated with other resource patterns, allocating it to multiple antennas by grouping resource elements, and transmitting using these antennas, while coordinating with neighboring cells to mute or hop CSI-RS transmissions to avoid collisions and optimize resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If new CSI-RS reference signals are introduced to support higher antenna configurations and improve system capacity, then channel quality estimation performance is improved, but transmission bandwidth availability decreases and coexistence with legacy systems becomes problematic
Solution Approach 1:
The patent segments the available resource elements into distinct patterns, allocating specific non-colocated resource elements for CSI-RS transmissions. This segmentation allows multiple CSI-RS signals to coexist in different frequency-time locations without interfering with each other or legacy signals, thereby enabling improved channel quality estimation while preserving transmission bandwidth for other purposes.
Solution Approach 2:
The patent introduces time-domain dimension by implementing duty cycling for CSI-RS transmissions. Instead of continuous transmission that would consume bandwidth, CSI-RS is transmitted periodically with configurable duty cycles. This dimensional approach allows the system to achieve accurate channel estimation over time while maintaining bandwidth availability during non-transmission periods.
2Productivity
If new CSI-RS reference signals are introduced to enhance system performance with higher antenna configurations, then data transmission performance is improved, but backward compatibility with legacy user equipment deteriorates
Solution Approach 1:
The patent applies local quality by making CSI-RS resource patterns cell-specific and configurable. Different cells can adopt different resource patterns and duty cycles based on their specific needs and legacy device density. This localized approach allows advanced features to be deployed where beneficial while maintaining compatibility in other areas, resolving the contradiction between enhanced performance and backward compatibility.
Solution Approach 2:
The patent implements dynamic configurability of CSI-RS parameters including resource patterns, density, and duty cycles. This dynamic approach allows the system to adapt transmission characteristics based on current network conditions and device capabilities, enabling high performance when needed while automatically degrading to legacy-compatible modes when dealing with older user equipment.
3Measurement precision
If CSI-RS transmission density is increased to improve channel estimation accuracy, then measurement precision is improved, but interference with legacy reference signals increases
Solution Approach 1:
The patent extracts CSI-RS transmissions from the same resource elements used by legacy reference signals by implementing non-colocated resource patterns. This separation removes the harmful interference issue entirely by ensuring CSI-RS and legacy RS occupy different frequency-time resources, allowing high-density CSI-RS transmission without degrading legacy signal quality.
Solution Approach 2:
The patent employs periodic duty-cycled transmission of CSI-RS signals rather than continuous transmission. This periodic approach allows the system to achieve necessary channel estimation accuracy through repeated measurements over time while reducing instantaneous transmission density, thereby minimizing interference with legacy reference signals during their transmission periods.
Data Source
AI summary
A method for wireless communication is disclosed which includes selecting a first resource pattern comprising resource elements that are non-colocated with a second resource pattern and allocating the first resource pattern to a plurality of antennas for transmitting a channel state information reference signal.