QCL-Based RRM Measurement in Carrier Aggregation
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Solution Overview
Problem
Current wireless access systems face challenges in efficiently performing Radio Resource Measurement (RRM) in synchronized cells when Quasi Co-Location (QCL) is applied, particularly in setting cyclic prefix lengths and allocating cell identifiers, which affects data transmission efficiency and synchronization.
Innovation Solution
The method involves a User Equipment (UE) receiving higher layer signals about QCL between Channel State Information Reference Signals (CSI-RS) and Cell-specific Reference Signals (CRS) of different cells, allowing for RRM in synchronized cells using CSI-RS and CRS from a synchronization reference cell, and maintaining synchronization using synchronization signals from the reference cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RRM is performed in synchronized cells using QCL between CSI-RS and CRS, then data transmission efficiency is improved, but device complexity increases due to multiple reference signal processing
Solution Approach 1:
The patent applies copying by having the UE perform RRM measurements on CSI-RS in the synchronized cell while using QCL information to copy/reference the CRS configuration from the reference cell. This allows efficient measurement without independently processing all reference signal parameters, thus improving productivity while managing device complexity.
Solution Approach 2:
QCL information acts as an intermediary that links the CSI-RS in the synchronized cell with the CRS in the reference cell. The higher layer signal providing QCL information enables the UE to understand the relationship between these reference signals, allowing efficient RRM measurement without direct processing of all signal parameters, thereby resolving the contradiction between transmission efficiency and processing complexity.
2Measurement precision
If QCL information is signaled through higher layer signaling, then measurement precision is improved, but loss of time increases due to signaling overhead
Solution Approach 1:
The patent applies preliminary action by providing QCL information through higher layer signaling in advance, before the actual RRM measurement process. This allows the UE to have the necessary configuration information ready, improving measurement precision while the signaling occurs once rather than repeatedly during measurements, thus managing the time loss.
3Device complexity
If synchronized cells do not transmit synchronization signals, then device complexity is reduced, but reliability of synchronization decreases
Solution Approach 1:
The reference cell acts as an intermediary for synchronization. The synchronized cell relies on the reference cell's synchronization signals and uses QCL information to maintain synchronization without transmitting its own synchronization signals. This reduces the complexity of signal transmission in synchronized cells while maintaining synchronization reliability through the reference cell's signals.
Solution Approach 2:
The reference cell provides universal synchronization service to multiple synchronized cells. Instead of each synchronized cell transmitting its own synchronization signals, a single reference cell's synchronization signals serve multiple cells, reducing overall system complexity while maintaining synchronization reliability across all synchronized cells.
Data Source
AI summary
The present invention relates to methods for making radio resource measurements in synchronized cells when quasi co-location is applied, and to apparatuses supporting same. A method for a terminal for making radio resource measurements (RRM) in a wireless access system according to one embodiment of the present invention may comprise the steps of: receiving an upper level signal comprising a reference signal for channel state information (CSI-RS) of a first cell, and quasi co-location (QCL) information for a cell-specific reference signal (CRS) and/or CSI-RS of a second cell; receiving the CRS and/or CSI-RS of the second cell on the basis of the QCL information; and measuring a first RRM for the first cell by means of the CRS and/or the CSI-RS of the second cell.