Adaptive SMTC Window Selection for NTN Power Efficiency
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Solution Overview
Problem
In Non-Terrestrial Networks (NTNs), the existing Synchronization Signal Block Measurement Time Configuration (SMTC) is not adapted to handle the unique challenges posed by satellite communications, such as varying propagation delays and Doppler shifts, leading to inefficient measurement processes and increased power consumption in user equipment (UE).
Innovation Solution
The UE is configured to obtain location and ephemeris data to determine whether to select measurement windows based on propagation delay, distance, and satellite movement, allowing it to activate SMTC windows only when relevant satellite signals are within the measurement window, reducing unnecessary measurements and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing SMTC configuration is used in NTN, then the measurement process covers all possible satellite signals, but it leads to increased power consumption and inefficient measurement processes due to varying propagation delays and Doppler shifts
Solution Approach 1:
The patent applies dynamics by making the SMTC window configuration adaptive rather than static. The network configures multiple SMTC window parameters (different durations, periodicities, and time offsets) and the UE dynamically selects the appropriate configuration based on current satellite signal conditions, propagation delay, and Doppler shift characteristics. This dynamic adaptation allows the system to maintain reliable measurement coverage while minimizing power consumption by activating only the necessary measurement windows.
Solution Approach 2:
The patent changes key parameters of the SMTC configuration including window duration, periodicity, and time offset based on NTN-specific conditions. By adjusting these parameters according to satellite orbit characteristics, propagation delay variations, and Doppler shifts, the system optimizes the balance between measurement reliability and energy efficiency, avoiding unnecessary measurements while ensuring adequate coverage of relevant satellite signals.
2Reliability
If extended SMTC windows are used to capture satellite signals with varying propagation delays, then measurement coverage is improved, but scheduling flexibility is reduced and measurement efficiency decreases
Solution Approach 1:
The patent segments the measurement process by dividing it into multiple SMTC window configurations, each optimized for specific satellite signal conditions. Instead of using a single extended SMTC window that reduces efficiency, the system creates multiple shorter, targeted measurement windows with different parameters. The UE selects and activates only the relevant segments based on current satellite visibility and signal characteristics, thereby maintaining comprehensive signal capture capability while preserving measurement efficiency through selective activation.
3Adaptability or versatility
If multiple SMTC window configurations are configured to handle different satellite conditions, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service by enabling the UE to autonomously select and activate the appropriate SMTC window configuration based on its own measurements of satellite signal conditions, propagation delay, and Doppler shift. The network provides multiple configuration options, but the UE independently determines which configuration is currently most suitable without requiring complex network control or coordination. This self-service approach enhances adaptability while managing device complexity by leveraging the UE's own sensing and decision-making capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the need for extended SMTC windows, enhances scheduling flexibility, and minimizes unnecessary measurements, thereby lowering power consumption and improving measurement efficiency in NTN environments.
Implementation Method 1
Propagation delay is an important aspect of satellite communications that is different from the delay expected in a terrestrial mobile system. For a bent pipe satellite network, the round-trip delay may, due to the orbit height, range from tens of ms in the case of LEO to several hundreds of ms for GEO.
Implementation Method 2
The interest to adapt NB-IoT and LTE-M for operation in NTN is growing. Two basic architectures have been considered. One is the transparent payload (also referred to as bent pipe architecture). The other is the regenerative payload.
Data Source
AI summary
A method (1000) performed by a wireless device (110) includes obtaining (1002) location information associated with the wireless device and/or ephemeris data for one or more satellite cells. The wireless device receives (1004) a measurement configuration to measure reference signals from the one or more satellite cells. The measurement configuration includes at least one measurement window. The wireless device determines (1006) whether to select a measurement window for the one or more satellite cells based on the location information associated with the wireless device and/or ephemeris data of the one or more satellite cells.