Small Cell Measurement Interference Cancellation Coverage Extension
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Solution Overview
Problem
In wireless communication systems where a macro cell and a small-scale cell coexist, terminals often find themselves outside the coverage of the small-scale cell, making traffic dispersion efforts ineffective due to the small coverage area of the small-scale cell.
Innovation Solution
A method and terminal that enable terminals to access and perform measurements within the coverage extension area of a small-scale cell by using an interference cancellation function to measure reference signal received power (RSRP) and received signal strength indicator (RSSI), specifically by configuring subframes for interference cancellation in the presence of neighbor cells, allowing effective RSRP and RSRQ measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a small-scale cell is deployed to disperse traffic from a macro cell, then traffic dispersion capability is improved, but coverage area remains too narrow to be effective
Solution Approach 1:
The patent changes the parameter of measurement configuration by introducing different subframe measurement patterns (first pattern for small cell, second pattern for macro cell) and applying interference cancellation techniques specifically during small cell measurements. This allows terminals to accurately measure RSRP and RSSI in the presence of macro cell interference, effectively extending the usable coverage area of the small-scale cell and enabling successful traffic dispersion.
2Ease of operation
If measurement for small cell is performed in coverage extension area, then access capability is improved, but measurement precision deteriorates due to macro cell interference
Solution Approach 1:
The patent converts the harmful macro cell interference into a beneficial measurement opportunity by configuring specific subframe patterns where the macro cell transmits reference signals. The terminal uses these known macro cell reference signals to perform interference cancellation, subtracting the predictable macro cell interference from the received signal to accurately measure small cell RSRP and RSSI even in coverage extension areas.
Solution Approach 2:
The patent applies preliminary action by configuring the terminal with advance knowledge of macro cell subframe measurement patterns and reference signal positions before performing small cell measurements. The terminal pre-configures interference cancellation parameters and uses predetermined macro cell reference signal patterns to eliminate interference, ensuring accurate measurements are performed before the terminal attempts to access the small cell.
3Measurement precision
If interference cancellation function is applied to measure RSRP and RSSI, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the measurement process into distinct time periods using different subframe measurement patterns. During first subframes dedicated to small cell measurement, the terminal applies interference cancellation using pre-configured macro cell reference signal patterns. During second subframes dedicated to macro cell measurement, the terminal performs standard measurements without interference cancellation. This temporal segmentation reduces overall processing complexity while maintaining measurement precision when needed.
Data Source
AI summary
The present specification provides a method for performing measurements, by a terminal, in a coverage extension area of a small-scale cell in a wireless communication system in which macro cell and the small-scale cell coexist. The method for performing measurements can include the steps of: receiving information about a first subframe on which measurements for the small-scale cell can be performed and information about a second subframe on which measurements for the macro cell can be performed; when an interference cancellation function is set, measuring reference signal received power (RSRP) and a received signal strength indicator (RSSI) for the small-scale cell by driving the interference cancellation function on the first subframe; and measuring RSRP on the second subframe for the macro cell by driving the interference cancellation function and measuring the RSSI for the macro cell without driving the interference cancellation function.