LEO Satellite Broadcast Using Walsh Codes for Low-Rate Delivery
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Solution Overview
Problem
Existing satellite network technologies face challenges in providing low data rate broadcast services without bidirectional communication, particularly due to bandwidth limitations and the need for permanent allocation of satellite resources, which complicates the delivery of content like traffic, weather, and emergency warnings to mobile devices using Low Earth Orbit (LEO) satellites.
Innovation Solution
A system and method that utilize a gateway to receive and compress data packets, select appropriate Walsh codes for transmission, and create RLC blocks for broadcasting content over a satellite network, allowing for unidirectional data transmission and efficient allocation of satellite resources, enabling low data rate broadcasts to mobile devices without the need for bidirectional communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If satellite networks are used for broadcast content delivery, then coverage area is improved, but bandwidth limitations and resource allocation complexity worsen
Solution Approach 1:
The patent segments broadcast content into different priority levels (high priority emergency warnings vs. low priority routine content) and allocates satellite resources accordingly. High priority content receives guaranteed bandwidth and permanent resource allocation, while low priority content uses available capacity without requiring permanent allocation, thus reducing overall resource allocation complexity while maintaining broad coverage
Solution Approach 2:
The patent dynamically adjusts transmission parameters including data rate, modulation scheme, and code allocation based on content priority and available satellite capacity. This allows the system to optimize resource usage for different types of content, reducing the need for permanent high-capacity allocations while maintaining coverage area
2Reliability
If permanent satellite bandwidth is allocated for broadcast services, then service reliability is improved, but satellite resource utilization worsens
Solution Approach 1:
The patent divides satellite bandwidth into reserved portions for high priority content (ensuring service reliability) and dynamic portions for low priority content (improving resource utilization). This segmentation allows permanent allocations only where necessary while maintaining high overall satellite utilization
Solution Approach 2:
The patent implements partial permanent allocation rather than full permanent allocation for all services. Only the minimum necessary bandwidth for reliable high priority content delivery is permanently allocated, while the remainder is available for dynamic allocation to low priority content, thus improving both reliability and utilization
3Reliability
If bidirectional communication is implemented for user authentication, then service security is improved, but airtime consumption and complexity worsen
Solution Approach 1:
The patent performs user authentication and authorization before the actual broadcast content transmission. By completing the bidirectional communication handshake in advance, the system ensures service security while allowing the subsequent broadcast to proceed using efficient unidirectional transmission, minimizing airtime consumption during content delivery
Data Source
AI summary
A system is disclosed for providing low data rate broadcast services. Different types of broadcast packets are detected among data packets received an external network. The different types broadcast packets contain different a different broadcast content. When a particular type of broadcast packet is detected, a transmit data rate is selected and Walsh codes are assigned for achieving the transmit data rate. Data packets corresponding to the broadcast packets are compressed, and at least one RLC block containing the compressed data packets is created. The RLC blocks are transmitted from a satellite using the assigned Walsh codes.