Small Cell Discovery Signal Muting Pattern for Interference Reduction
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Solution Overview
Problem
In broadband wireless communications networks, especially in E-UTRAN, small cell discovery is hindered by interference between discovery signals of small cells and macrocells, leading to inefficient cell association and prolonged acquisition times due to simultaneous transmission on the same time and frequency resources.
Innovation Solution
Implementing a discovery signal muting pattern that intermittently mutes discovery signal transmissions and varies subframes, OFDMA symbol positions, and carriers, allowing eNBs to transmit primary and secondary synchronization signals during specific radio frames, thereby reducing interference and optimizing resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If small cells and macrocells transmit discovery signals simultaneously on the same time and frequency resources, then resource utilization is maximized, but interference between cells increases and small cell discovery efficiency deteriorates
Solution Approach 1:
The patent implements discovery signal muting patterns where small cells periodically transmit discovery signals in specific subframes while remaining silent in others. This periodic transmission schedule allows macrocells to transmit discovery signals in subframes where small cells are muted, eliminating interference while maintaining resource utilization through structured time-division multiplexing.
Solution Approach 2:
The patent segments the radio frame structure into different subframes with specific functions. Discovery signal transmission is segmented into designated subframes for macrocells and other subframes for small cells. This segmentation of time resources allows different cell types to operate without interference while maintaining overall system efficiency.
2Reliability
If discovery signals are transmitted continuously to improve discovery reliability, then cell association reliability improves, but acquisition time increases due to interference
Solution Approach 1:
By implementing periodic discovery signal transmission with muting patterns, the patent ensures that discovery signals are transmitted reliably in interference-free subframes. This periodic approach maintains cell association reliability while reducing acquisition time compared to continuous transmission in the presence of interference.
Solution Approach 2:
The patent converts the potential harm of continuous transmission (interference) into a benefit by using structured muting patterns. The periodic silence periods create interference-free windows that improve signal detectability and reduce acquisition time, while the transmission periods maintain reliability.
3Productivity
If all cells use the same time and frequency resources for discovery signals, then resource efficiency is maximized, but device complexity increases due to interference management requirements
Solution Approach 1:
The patent reduces device complexity by implementing periodic muting patterns that are predetermined and standardized. Devices can follow simple, predefined transmission schedules rather than requiring complex real-time interference coordination, maintaining resource efficiency while simplifying implementation.
Solution Approach 2:
The patent changes the time-domain parameters of discovery signal transmission by introducing periodic muting patterns. This parameter change transforms the transmission behavior from continuous to periodic, reducing interference management complexity while maintaining resource efficiency through structured time-division multiplexing.
Data Source
AI summary
Techniques for efficient small cell discovery are described. In one embodiment, for example, an evolved node B (eNB) may comprise logic, at least a portion of which is in hardware, the logic to determine a discovery signal transmission schedule for a series of radio frames based on a discovery signal muting pattern specifying at least one discovery-muted radio frame among the series of radio frames, and a transceiver to transmit at least one primary synchronization signal (PSS) and at least one secondary synchronization signal (SSS) during the series of radio frames according to the discovery signal transmission schedule. Other embodiments are described and claimed.