CSI-RS Mapping Patterns for Extended Cyclic Prefix Subframes
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Solution Overview
Problem
In massive MIMO wireless communication systems, existing methods face challenges in efficiently allocating resources for channel state information reference signals (CSI-RS) in subframes with extended cyclic prefix, particularly when dealing with a large number of antenna ports, leading to reduced throughput and increased interference.
Innovation Solution
The method involves generating and mapping CSI-RS sequences to specific patterns within the subframe, utilizing existing resource elements and adding new ones to support multiple antenna ports, optimizing the placement of CSI-RS patterns across OFDM symbols to maximize resource utilization and minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If existing resource allocation methods are used for CSI-RS in extended CP subframes, then resource utilization is limited, but the number of supported antenna ports is insufficient
Solution Approach 1:
The patent segments the extended CP subframe structure into specific resource element patterns, defining distinct CSI-RS mapping patterns for different antenna port counts (1, 2, 4, 8 ports). This segmentation allows efficient resource allocation by matching specific patterns to specific antenna configurations, resolving the contradiction between supporting multiple antenna ports and maintaining resource utilization efficiency.
2Measurement precision
If more antenna ports are added to support massive MIMO, then channel state information estimation improves, but interference between reference signals increases
Solution Approach 1:
The patent applies local quality by assigning specific resource element patterns to different antenna port configurations. Each pattern is optimized for its specific antenna port count, with resource elements distributed in distinct locations within the time-frequency grid. This localized optimization ensures that reference signals for different antenna ports do not overlap, reducing interference while maintaining accurate channel state information estimation for massive MIMO systems.
3Quantity of substance
If resource elements are densely allocated for CSI-RS, then more antenna ports can be supported, but throughput is reduced
Solution Approach 1:
The patent implements dynamic resource allocation by providing different CSI-RS mapping patterns that can be selected based on the actual number of antenna ports in use. Rather than always using dense allocation, the system dynamically chooses the appropriate pattern (for 1, 2, 4, or 8 antenna ports), optimizing the balance between supporting multiple antenna ports and maintaining data throughput by allocating resources only where needed.
Data Source
AI summary
A method for transmitting a channel state information reference signal (CSI-RS) in a specific downlink subframe having an extended cyclic prefix (CP) in a wireless communication system according to an embodiment of the present invention includes: generating a CSI-RS sequence and mapping the CSI-RS sequence to CSI-RS complex-valued modulation symbols; and mapping the CSI-RS complex-valued modulation symbols to at least one pattern of a first CSI-RS pattern set composed of a plurality of CSI-RS patterns and a second CSI-RS pattern set composed of a plurality of CSI-RS patterns, the CSI-RS patterns being composed of REs to which CSI-RS complex-valued modulation symbols are mapped, wherein the second CSI-RS pattern set is available when 2 OFDM symbols are used for a physical downlink control channel in the downlink subframe or a specific downlink control information format is configured.