LTE Satellite Cell Selection Algorithm for Load Balancing
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Solution Overview
Problem
Existing LTE specifications are designed for terrestrial usage and do not effectively address cell selection and reselection for Mobile Satellite Equipment (MSE) in satellite environments, where beam power extends beyond physical locations and multiple providers may not be available, leading to overloading and connectivity issues.
Innovation Solution
A load balancing algorithm is implemented to distribute subscribers evenly among base stations, using GPS location information to assist in cell selection and continuing to search for suitable cells as a fallback, with Satellite Base Station Equipment (SBSE) broadcasting load levels and beam shape metadata to guide Mobile Satellite Equipment (MSE) in selecting non-loaded cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing 3GPP LTE specifications are used for cell selection, then terrestrial communication is supported, but satellite environment cell selection fails due to beam power extending beyond physical locations
Solution Approach 1:
The patent modifies cell selection parameters by introducing beam shape metadata and location information as new selection criteria. The MSE uses GPS location to determine if it falls within the beam footprint area, and the cell selection algorithm is changed to consider beam shape parameters (azimuth, elevation, half-power beamwidth) in addition to traditional signal strength metrics, enabling reliable satellite environment cell selection.
Solution Approach 2:
The patent creates a universal cell selection algorithm that works for both terrestrial and satellite environments. The SBSE broadcasts beam shape metadata that can be used by MSE for cell selection in satellite mode, while maintaining compatibility with traditional LTE cell selection procedures for terrestrial use, making the system multi-functional across different deployment scenarios.
2Device complexity
If a single Satellite Access Controller serves all subscribers, then network simplicity is maintained, but the SAC becomes overloaded
Solution Approach 1:
The patent segments the subscriber base by introducing load level flags that divide cells into loaded and non-loaded categories. The load balancing algorithm segments traffic distribution by directing MSE to camp on non-loaded cells when available, effectively partitioning the SAC workload across multiple cells and preventing any single SAC from becoming overloaded.
Solution Approach 2:
The patent implements dynamic load balancing where the SBSE continuously monitors cell load conditions and updates load level flags in real-time. The load level flag changes dynamically based on current subscriber distribution, enabling the network to adaptively redistribute traffic from overloaded cells to underutilized cells, maintaining optimal SAC processing capacity utilization.
3Ease of operation
If MSE selects cells based on beam power alone, then simple selection is achieved, but overloading occurs when beam power extends beyond physical location
Solution Approach 1:
The patent introduces beam shape metadata as an intermediary layer between the physical beam and the MSE. The metadata (azimuth, elevation, half-power beamwidth) acts as a mediator that translates the physical beam characteristics into a usable selection criterion. The MSE uses this intermediary information along with GPS location to determine if it falls within the beam footprint, enabling accurate cell selection without requiring complex signal strength measurements.
Solution Approach 2:
The patent performs preliminary cell selection filtering by having the SBSE broadcast beam shape metadata before the MSE attempts to camp. The MSE uses this advance information combined with its GPS location to pre-determine which cells are suitable for camping, filtering out unsuitable cells before the actual selection process. This preliminary action prevents MSE from attempting to camp on cells where the beam power does not actually reach, avoiding overloading issues.
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 solution prevents overloading of Satellite Access Controllers, ensures even distribution of load across cells, and maintains connectivity by allowing MSE to select cells based on available capacity and location, even in single-provider satellite networks.
Implementation Method 1
the MSE may use Global Positioning System (GPS) location information, when available, to assist in selecting a cell in range suitable for camping in the satellite environment
Data Source
AI summary
According to various aspects of the subject technology, methods and systems for providing cell selection and reselection for Long Term Evolution (LTE) communications over satellite are provided. The disclosure addresses several problems specific to satellite over LTE, including compensation of beam coverage extending beyond the physical location of the beam due to flatness of the beam, load balancing of cells with overlapping coverage, and modified cell selection in a single provider network when no suitable cells are found.