Satellite Random Access Resource Groups for GNSS-Free Terminals
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Solution Overview
Problem
Terminal devices without GNSS capability face challenges in accessing satellites due to high mobility-induced frequency offsets, leading to inter-carrier interference and reduced success rates in satellite communication, particularly in IoT applications.
Innovation Solution
Configuring multiple groups of random access resources with varying subcarrier spacings and positions to enable terminal devices to select appropriate resources based on their GNSS capability or preamble type, reducing interference and correcting frequency offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If terminal devices without GNSS capability attempt to access satellite using conventional single-group random access resources, then device cost is reduced, but frequency offset synchronization fails leading to access failure
Solution Approach 1:
The random access resources are segmented into multiple groups, where each group is configured with different subcarrier spacings. Terminal devices can select the appropriate group based on their GNSS capability, allowing devices without GNSS to use groups with larger subcarrier spacings that are more robust to frequency offsets, thereby achieving successful access without requiring expensive GNSS hardware.
Solution Approach 2:
The patent changes the subcarrier spacing parameter across different random access resource groups. By configuring multiple groups with varying subcarrier spacings (e.g., different numerologies), the system enables terminal devices to adapt to different frequency offset conditions, improving access success for low-cost devices without GNSS while maintaining compatibility with high-performance devices.
2Reliability
If multiple groups of random access resources with different subcarrier spacings are configured, then frequency offset resistance is improved, but resource configuration complexity increases
Solution Approach 1:
The patent introduces dynamic resource selection where terminal devices dynamically choose the appropriate random access resource group based on their capability indicators (e.g., GNSS availability). This dynamic adaptation allows the system to maintain high reliability across different device types while keeping the configuration manageable through standardized selection criteria.
Solution Approach 2:
The network device performs preliminary configuration by pre-defining multiple groups of random access resources with different subcarrier spacings and associating them with specific capability indicators. This preliminary setup eliminates the need for complex real-time negotiations, as terminal devices can directly select the appropriate pre-configured group based on their capabilities, simplifying the overall configuration process.
Data Source
AI summary
A communication method and apparatus are provided, to enable various terminal devices to successfully access a satellite. A terminal device receives, from a network device, configuration information that indicates at least two groups of random access resources, where any group of random access resources includes a plurality of subcarriers in frequency domain, and subcarrier spacings included in the at least two groups of random access resources in frequency domain are different. The terminal device selects one group of random access resources from the at least two groups of random access resources based on first information, and sends a random access preamble to the network device based on the selected group of random access resources. The first information is information indicating whether the terminal device supports a global navigation satellite system (GNSS) capability, or is a random access preamble type selected by the terminal device.