CSI-RS Resource Allocation for Legacy Compatibility
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Solution Overview
Problem
The introduction of new reference signals in wireless communication systems, such as CSI-RS, poses challenges related to available transmission bandwidth, backward compatibility with legacy user equipment, and coexistence with existing reference signals, leading to performance degradation and compatibility issues.
Innovation Solution
The solution involves controlling the density and duty cycle of CSI-RS transmissions by allocating a specific number of resource elements (REs) and using hopping patterns to avoid collisions, ensuring backward compatibility and optimizing channel estimation performance while minimizing impact on legacy UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If new reference signals (CSI-RS) are introduced to support higher data rates and throughput, then system capacity and performance are improved, but available transmission bandwidth is reduced and coexistence with legacy reference signals becomes problematic
Solution Approach 1:
The patent segments the transmission bandwidth by allocating specific resource elements (REs) exclusively for CSI-RS transmissions, separating them from legacy reference signals and data transmissions. This segmentation allows CSI-RS to obtain dedicated resources for channel estimation while legacy signals maintain their原有 resources, thus improving system capacity without completely consuming available bandwidth.
Solution Approach 2:
The patent introduces CSI-RS in the time-frequency domain by allocating specific subframes and resource blocks for CSI-RS transmissions, adding a new dimensional structure to the transmission framework. This dimensional approach allows multiple reference signals to coexist in different time-frequency resources, resolving the bandwidth conflict between new and legacy signals.
2Measurement precision
If new reference signals (CSI-RS) are introduced to improve channel estimation accuracy, then measurement precision is improved, but backward compatibility with legacy user equipment deteriorates
Solution Approach 1:
The patent applies local quality by making CSI-RS transmissions cell-specific and UE-specific, where only equipped UEs measure and process CSI-RS while legacy UEs ignore these resources. This localized approach allows advanced channel estimation where needed without forcing legacy UEs to adapt, thus maintaining backward compatibility while improving measurement precision for supported devices.
Solution Approach 2:
The patent uses resource element allocation patterns as an intermediary mechanism that enables CSI-RS transmissions without directly interfering with legacy signal processing. By defining specific RE patterns that legacy UEs can skip or ignore, the system mediates between new and old equipment, allowing coexistence where legacy UEs maintain their原有 functionality while advanced UEs utilize CSI-RS for improved channel estimation.
3Measurement precision
If density of CSI-RS transmissions is increased to improve channel estimation performance, then measurement precision is improved, but interference with legacy systems increases
Solution Approach 1:
The patent employs periodic action by transmitting CSI-RS in specific periodic subframes rather than continuously. This periodic transmission pattern allows channel estimation to be performed at intervals sufficient for mobility scenarios while leaving other subframes available for legacy transmissions without interference, thus balancing measurement precision with legacy system protection.
Solution Approach 2:
The patent applies partial action by allocating only a portion of available resources to CSI-RS transmissions rather than using full bandwidth continuously. This partial resource allocation provides sufficient channel estimation performance for mobile scenarios while leaving remaining resources untouched for legacy signals, thereby minimizing interference with legacy systems while achieving adequate measurement precision.
Data Source
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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.