LTE Reference Signal Density for Interference Measurement
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Solution Overview
Problem
In LTE systems, accurate interference measurement is hindered by the low density of CSI-RS, making it difficult to distinguish interference from multiple transmission points with the same cell ID, and existing methods rely on CRS which are not effective in high-density scenarios.
Innovation Solution
A radio communication system with base stations that transmit high-density CSI-RSs for channel state measurement and interference measurement, using a second reference signal for interference measurement, and notifying mobile terminals of the assignment patterns to enable precise interference measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CSI-RS is used for interference measurement in LTE-A systems, then it is possible to divide reference signals from multiple transmission points, but the low density of CSI-RS makes it difficult to measure interference with high accuracy
Solution Approach 1:
The patent combines CRS and CSI-RS into a unified reference signal structure where CRS is configured with the same cell ID as the serving cell, allowing the mobile terminal to measure both channel state and interference using a single reference signal framework, thereby achieving high-density interference measurement while maintaining the ability to distinguish transmission points
Solution Approach 2:
The patent changes the configuration parameters of CRS by assigning it the same cell ID as the serving cell and configuring it with specific density patterns, transforming it from a traditional cell-identification signal into a dual-purpose signal that enables both channel state measurement and high-precision interference measurement
2Productivity
If CRS is used for interference measurement, then it is available in LTE systems, but it cannot divide CRSs transmitted from multiple transmission points with the same cell ID
Solution Approach 1:
The patent segments the reference signal functionality by configuring CRS with the same cell ID as the serving cell, allowing the mobile terminal to separately identify and measure signals from the serving transmission point and interfering transmission points based on their distinct CRS configurations, thereby enabling multi-point differentiation while maintaining LTE compatibility
Data Source
AI summary
To increase the number of CSI-RSs for interference measurement to improve interference measurement accuracy, a first reference signal for channel state measurement and a second reference signal for interference measurement are assigned to reference signal resources defined for transmission of the first reference signal, and a mobile terminal apparatus that supports both the first reference signal and the second reference signal is notified of pattern information to identify an assignment pattern of the first reference signal and the second reference signal. A second mobile terminal apparatus that supports the first reference signal and that does not support the second reference signal is notified of pattern information to identify an assignment pattern of the first reference signal, and of assignment information indicating that resources assigned the second reference signal are assigned a third reference signal of zero power for channel state measurement.