Adaptive Coding Modulation for Spot Beam Satellite Broadcast
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Solution Overview
Problem
Satellite communication systems face challenges in maintaining reliable signal quality due to varying atmospheric conditions, particularly rain-induced attenuation, which requires high transmitter power and is economically and technologically impractical, and existing solutions do not effectively adapt signal transmission modes to optimize resource allocation.
Innovation Solution
A method and apparatus that adaptively control transmission signals by selecting modulation schemes, code schemes, and code rates based on real-time or predicted propagation characteristics, allowing for dynamic adjustment of signal power and error correction to maintain optimal signal quality within power and bandwidth constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmitter power is increased to maintain minimum CNR in all regions during heavy rain, then signal quality reliability is improved, but satellite weight and cost increase significantly
Solution Approach 1:
The patent implements adaptive transmission by dynamically changing modulation schemes and coding rates based on real-time atmospheric conditions. The system transitions from static high-power transmission to dynamic transmission modes that adjust to weather conditions, reducing the need for excessive satellite power while maintaining reliability during rain events.
Solution Approach 2:
The system changes transmission parameters including modulation type (QPSK, 8PSK, 16PSK), coding rates (1/2, 2/3, 3/4, 5/6), and power levels based on measured or predicted rain attenuation. This allows the same satellite to operate efficiently under different atmospheric conditions without requiring oversized power infrastructure.
2Reliability
If transmitter power is increased to compensate for atmospheric attenuation, then carrier to noise ratio is improved, but system cost and power consumption increase
Solution Approach 1:
The system dynamically adjusts transmission power and modulation schemes based on atmospheric conditions. During clear weather, lower power and higher-order modulation are used to save energy. During rain events, the system switches to more robust modulation and error correction codes, adjusting power levels as needed rather than maintaining constant high power.
Solution Approach 2:
The adaptive coding and modulation system maintains continuous reliable transmission by continuously monitoring atmospheric conditions and adjusting transmission parameters in real-time, ensuring uninterrupted service while optimizing power consumption based on actual channel conditions rather than worst-case scenarios.
3Reliability
If high power transmission is used to ensure minimum CNR everywhere, then signal coverage is improved, but bandwidth efficiency decreases
Solution Approach 1:
The system applies different transmission characteristics to different spatial regions based on local atmospheric conditions. Instead of uniform high-power transmission across the entire coverage area, the system adjusts modulation and coding rates locally for each spot beam based on measured rain attenuation in that specific region, optimizing both coverage and bandwidth efficiency.
Solution Approach 2:
The patent implements dynamic adaptation of transmission modes for each spot beam based on real-time atmospheric conditions. The system can switch between multiple modulation schemes (QPSK, 8PSK, 16PSK) and coding rates depending on the current channel conditions in each region, maximizing bandwidth efficiency while maintaining reliable coverage.
Data Source
AI summary
A method and apparatus for adaptively controlling a transmission signal for transmission to at least one receiver in a terrestrial region is disclosed. The method selects a transmission signal mode having a modulation scheme, code scheme, and code rate from a plurality of transmission signal modes according to received information, generates a transmission signal according to the selected mode, and transmits the generated transmission signal to the receiver.