Cell Selection Offset for Small Cell Aggregation
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Solution Overview
Problem
In next-generation mobile communication systems with overlapping macro and small cells, user terminals face difficulties in selecting small cells using high frequency bands due to increased path loss and differing transmission properties, leading to suboptimal communication speeds and coverage.
Innovation Solution
A cell selection method where the macro base station determines and reports an offset value to the user terminal based on transmission property information of small cells, allowing the terminal to measure and select cells considering factors like antenna elements, beamforming gain, and transmission bandwidth, thereby enhancing the ability to choose small cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a user terminal selects cells based on received quality of reference signals only, then the cell selection process is simple, but the user terminal cannot aggressively select small cells using high frequency bands due to increased path loss
Solution Approach 1:
The patent introduces an offset value parameter that modifies the cell selection criterion. The user terminal compares received quality against a threshold that incorporates this offset value, which is determined based on transmission property information of the second carrier. This parameter change enables the terminal to aggressively select small cells despite higher path loss, resolving the contradiction between simple selection process and improved communication speed.
2Quantity of substance
If small cells use a second carrier of high frequency band to increase capacity, then the capacity of small cells becomes bigger, but the path loss increases making it difficult for user terminals to select these cells
Solution Approach 1:
The patent introduces an offset value as an intermediary element that mediates between the high capacity benefit and the high path loss drawback of second carrier small cells. This offset value, reported from the base station to the user terminal, compensates for the path loss effect in the cell selection process, enabling terminals to select small cells on the second carrier despite the harmful path loss, thus resolving the contradiction.
3Productivity
If the user terminal aggressively selects small cells, then communication speed improves, but the cell selection becomes more complex due to additional offset value processing
Solution Approach 1:
The patent applies preliminary action by having the base station pre-calculate and report the offset value to the user terminal before the terminal performs cell selection. The base station determines the offset value based on transmission property information of the second carrier, so when the terminal receives this offset value, it can directly use it in the cell selection process without performing complex calculations itself. This reduces terminal complexity while enabling aggressive small cell selection for improved communication speed.
Data Source
AI summary
A user terminal selects small cells in a radio communication system in which a macro cell and small cells are arranged to overlap each other. In the cell selection method of the present invention, a macro base station to form a macro cell carries out the steps of determining the offset value to use in cell selection in a user terminal based on transmission property information of a second carrier in the small cell, and reporting the offset value to the user terminal. Also, the user terminal carries out the steps of measuring the received quality of reference signals from the macro base station and the small base station, receiving the offset value that is reported from the macro base station, and carrying out cell selection based on the received quality that is measured and the offset value that is received.