Terminal RRM Measurement Using Discovery Signal Subframes
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Solution Overview
Problem
In environments with both macrocells and small cells, existing technologies face challenges in efficiently measuring Radio Resource Management (RRM) and signaling for RRM measurement, particularly due to interference and state changes of small cells.
Innovation Solution
A method and apparatus that allow a terminal to efficiently measure RRM by receiving discovery signals from small cells, determining measurement subframes, and using Measurement Gaps (MGs) to differentiate between measurement and non-measurement subframes, enabling accurate RRM measurement regardless of small cell states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a terminal measures RRM of small cells in a mixed macrocell-small cell environment, then the ability to discover and measure small cells is improved, but measurement accuracy deteriorates due to interference from macrocells and state changes of small cells
Solution Approach 1:
The patent segments the measurement process by dividing subframes into measurement subframes and non-measurement subframes. Measurement subframes are specifically designated for RRM measurement of small cells, while non-measurement subframes are used for normal communication or macrocell operations. This segmentation allows the terminal to focus measurement resources on appropriate subframes, improving measurement accuracy by avoiding interference from macrocells during measurement subframes.
Solution Approach 2:
The patent applies preliminary action by configuring measurement subframe patterns in advance before RRM measurement begins. The network pre-configures which subframes will be used for measurement purposes, allowing the terminal to know beforehand when to perform measurements. This preliminary configuration enables the terminal to align its measurement activities with favorable conditions, such as when macrocell transmissions are reduced or absent, thereby improving measurement accuracy.
2Adaptability or versatility
If small cells frequently change states (transmitting discovery signals vs. not transmitting), then adaptability to different transmission conditions is improved, but measurement reliability deteriorates due to state conversion delays and interference
Solution Approach 1:
The patent applies dynamics by enabling small cells to flexibly change their transmission states (transmitting discovery signals vs. not transmitting) based on network conditions and load requirements. The measurement subframe pattern configuration allows the system to adapt to these dynamic state changes, ensuring that measurement opportunities are available regardless of the small cell's current transmission state. This dynamic approach maintains measurement reliability by providing multiple measurement opportunities across different subframes.
Solution Approach 2:
The patent uses periodic action through the measurement subframe pattern, which defines periodic intervals where measurement can occur. Even when small cells change states frequently, the periodic measurement subframes ensure that measurements are taken at regular intervals, providing consistent measurement opportunities. This periodic structure helps average out the effects of state changes and reduces the impact of state conversion delays on overall measurement reliability.
3Measurement precision
If measurement subframe patterns are configured to avoid macrocell interference, then measurement accuracy is improved, but time resources for measurement are reduced
Solution Approach 1:
The patent applies parameter changes by allowing flexible configuration of measurement subframe patterns with varying parameters such as measurement period, subframe offset, and pattern length. The network can adjust these parameters to optimize the balance between measurement accuracy and time resource utilization. For example, if interference conditions are favorable, the measurement period can be shortened to allocate more time resources, whereas under poor interference conditions, the pattern can be extended to improve accuracy.
Data Source
AI summary
In an environment in which a macrocell and a plurality of small cells exist, a terminal receives a discovery signal from a first small cell adjacent to the terminal among the plurality of small cells. When the first small cell is in a predetermined state, the terminal measures RRM of the first small cell based on the discovery signal.