Cell Detection Reference Signal Resource Allocation
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Solution Overview
Problem
In LTE-Advanced systems, the increased density of small cells leads to a decrease in frequency use efficiency for cell detection reference signals, as existing reference signals like CSI-RS are used for both data transmission and cell detection, resulting in reduced resource availability for data transmission.
Innovation Solution
The proposed solution involves configuring cell detection reference signals to be transmitted in a subset of resources allocated for other reference signals within a subframe, allowing for efficient use of resources and minimizing interference, thereby maintaining frequency use efficiency even at high small cell densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing reference signals like CSI-RS are used for both data transmission and cell detection, then resource utilization is maximized, but frequency use efficiency decreases due to reduced resource availability for data transmission
Solution Approach 1:
The patent segments the resource allocation by introducing a dedicated resource for cell detection reference signals that is separate from the CSI-RS resources. This segmentation allows cell detection functions to be performed without interfering with data transmission resources, thereby resolving the contradiction between versatile resource utilization and frequency use efficiency.
Solution Approach 2:
The patent introduces a new intermediary resource element specifically for cell detection reference signals. This intermediary resource acts as a mediator between the cell detection function and the data transmission function, allowing both to coexist without mutual interference and maintaining both adaptability and frequency use efficiency.
2Object-affected harmful factors
If cell detection reference signals are transmitted with long transmission intervals to suppress interference and power consumption, then interference suppression and power saving are improved, but measurement accuracy for RRM deteriorates
Solution Approach 1:
The patent performs preliminary configuration where the network notifies the terminal in advance about the transmission timing and resources of cell detection reference signals. This preliminary action allows the terminal to prepare measurement configurations and synchronize accordingly, enabling accurate RRM measurements even when signals are transmitted with longer intervals to suppress interference.
Solution Approach 2:
The patent implements a feedback mechanism where the terminal reports measurement results of cell detection reference signals to the network. This feedback loop allows the network to adjust transmission intervals and resources dynamically, balancing interference suppression with sufficient measurement accuracy for RRM functions.
3Productivity
If small cells are arranged in high density to accommodate increased traffic, then traffic capacity is improved, but interference between small cells increases
Solution Approach 1:
The patent applies local quality by assigning dedicated resources for cell detection reference signals specifically for each small cell. This localized resource allocation ensures that each small cell can transmit its detection signal without interference from neighboring small cells, enabling high-density deployment while maintaining low interference levels.
Solution Approach 2:
The patent resolves the interference issue by moving to another dimension of resource allocation. Instead of competing for the same time-frequency resources, each small cell is assigned a dedicated resource dimension for cell detection, allowing high-density spatial arrangement without mutual interference in the detection domain.
Data Source
AI summary
A reception processor receives the cell detection reference signals, each of the cell detection reference signals being transmitted from corresponding one of a plurality of cells. An RRM report generator generates measurement information indicating a measurement result of reception quality measured using the cell detection reference signal. A transmission processor transmits the measurement information. The cell detection reference signals are mapped to any one of a plurality of candidate resources, which is a part of a plurality of resources set for other reference signals in a subframe to which the cell detection reference signals are mapped.