Satellite Beam Switching Traffic Duplication for Outage Reduction
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Solution Overview
Problem
In satellite spot beam networks, beam switching results in significant user data traffic outages due to the need for multiple round trips to establish a new transmission link, wide aperture aloha messages, and bandwidth assignment delays, which disrupt services like voice over IP and web browsing.
Innovation Solution
A method and system that initiate a beam switch by duplicating user traffic over a new beam before the User Terminal (UT) arrives, assigning Time Division Multiplex Access (TDMA) allocations, and synchronizing timing without round trips, ensuring uninterrupted data flow by redirecting traffic via the old beam to the new beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UT pauses all user data traffic before switching beams and waits for successful link establishment, then the transmission link reliability is improved, but the user data outage time increases significantly
Solution Approach 1:
The gateway performs preliminary actions by pre-establishing the transmission link and pre-assigning bandwidth resources in the new beam before the UT actually switches to it. The gateway sends a handover notification to the new gateway, which then proactively sets up the RF link and allocates bandwidth, so that when the UT switches beams, data transmission can resume immediately without waiting for post-switch link establishment and bandwidth assignment.
2Measurement precision
If the UT transmits a burst into a wide aperture at the gateway for timing offset location, then the timing synchronization accuracy is improved, but the round trip message transmission time increases by approximately 0.5 seconds
Solution Approach 1:
The gateway performs timing synchronization preliminarily by sending a handover notification that includes pre-calculated timing offset information to the new gateway. This eliminates the need for the UT to transmit timing offset location bursts and wait for feedback messages, as the timing information is provided in advance, reducing the round trip time while maintaining synchronization accuracy.
3Measurement precision
If the gateway waits to send bandwidth assignments until receiving a message from the terminal, then the bandwidth allocation accuracy is improved, but the additional message exchange increases the outage time
Solution Approach 1:
The gateway performs preliminary bandwidth allocation by sending a handover notification that includes pre-assigned bandwidth information to the new gateway. This allows the new gateway to have bandwidth resources ready before the UT switches beams, eliminating the need for post-switch bandwidth assignment messages and reducing outage time while maintaining accurate bandwidth allocation based on UT requirements.
Data Source
AI summary
A system and method for beam switching by a User Terminal (UT). The method includes initiating a beam switch between an old beam and a new beam when the UT is disposed in an overlap area of the old beam and the new beam; duplicating over the new beam, at a Network Access Point (NAP), user traffic to the UT; and assigning a Time Division Multiplex Access (TDMA) allocation for the UT on the new beam, prior to an arrival of the UT on the new beam, where the user traffic traversing a satellite network remains uninterrupted during the beam switch and the NAP redirects user traffic for the UT via the old beam to the new beam.