Satellite Timing Synchronization via Beam Hopping Feedback
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Solution Overview
Problem
Current satellite communication systems lack an effective method to synchronize the satellite clock with exact time, leading to inefficiencies in beam hopping operations, which affect co-channel interference, frequency reuse, and network coverage.
Innovation Solution
A closed-loop feedback system is implemented to synchronize satellite switching instants with gateway switching instants using timing markers and a Beam Hopping Time Plan (BHTP), allowing for dynamic adjustment of timing and symbol rates to align guard periods with satellite switching events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If beam hopping is implemented to dynamically change routing, then network flexibility and capacity utilization are improved, but timing synchronization between satellite and gateway becomes difficult to maintain
Solution Approach 1:
The patent implements a feedback mechanism where the satellite transmits timing markers in each beam, the gateway detects these markers, measures the time difference between expected and actual arrival times, and adjusts its switching instants accordingly to maintain synchronization with the satellite's beam hopping schedule
Solution Approach 2:
The patent uses guard periods placed before timing markers in each beam transmission as a preliminary action to allow the gateway to prepare for and accurately detect the timing markers, ensuring precise timing measurement and synchronization adjustment
2Adaptability or versatility
If satellite switching instants are made programmable for beam hopping, then beam hopping capability is enabled, but exact time synchronization with terrestrial clock is lost
Solution Approach 1:
The satellite transmits timing markers that provide feedback to the gateway about the actual timing of beam switching, allowing the gateway to synchronize its programmable switching instants with the satellite's actual switching times, thereby maintaining both beam hopping flexibility and precise time synchronization
Solution Approach 2:
Timing markers serve as an intermediary element that carries timing information from the satellite to the gateway, enabling the gateway to accurately determine and align its switching instants with the satellite's beam hopping schedule without direct clock connection
3Measurement precision
If timing markers are transmitted in each beam, then synchronization information is provided, but signal complexity and overhead increase
Solution Approach 1:
The patent transmits timing markers periodically at fixed intervals within each beam's signal structure, allowing the gateway to predict and efficiently detect these markers using periodic correlation techniques, thereby maintaining synchronization accuracy without excessive complexity
Data Source
AI summary
A system and method for timing synchronization of satellite switching instants with gateway switching instants is described. The method includes: generating satellite switching instants according to a Beam Hopping Time Plan (BHTP); generating gateway switching instants according to the BHTP; transmitting a channel addressed to a plurality of beams hopped according to the BHTP based on the gateway switching instants, wherein each of the plurality of beams includes a signal including timing markers and a guard period at an end of the signal for the respective beam; receiving a synchronization information, without a loopback beam, for one of the plurality of beams; determining an adjustment period and an adjusted symbol rate for the generating of the gateway switching instants, based on the synchronization information, for a transmission of the channel such that at least a portion of the guard period in a respective signal for a respective beam aligns with one of the satellite switching instants; and adjusting a timing and a symbol rate of the transmission according to the adjustment period and the adjusted symbol rate, respectively.