Adaptive Coding Modulation Transceiver Through Dynamic SNR Thresholding
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Solution Overview
Problem
Wireless communication systems face challenges in maximizing throughput due to dynamic changes in signal-to-noise ratio (SNR) caused by fading characteristics of the communication channel, particularly in troposcatter channels, where existing systems fail to adapt effectively to changing atmospheric conditions.
Innovation Solution
An adaptive coding and modulation (ACM) transceiver system that continuously monitors and adjusts the SNR threshold for each modulation and coding scheme, using a controller to select the optimal scheme for transmission based on reported SNR values from return signals, thereby adapting to both fast and slow fading conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed MODCOD scheme is used for transmission, then device complexity is reduced, but throughput cannot be maximized under dynamic SNR conditions
Solution Approach 1:
The patent implements dynamic adaptation by continuously monitoring SNR and adjusting the MODCOD scheme in real-time. The system transitions from a static fixed MODCOD approach to a dynamic adaptive approach where transmission parameters change based on current channel conditions, thereby maximizing throughput without requiring overly complex systems.
Solution Approach 2:
The system employs feedback mechanisms where the receiver measures SNR and sends this information back to the transmitter. The transmitter uses this feedback to select the appropriate MODCOD scheme, creating a closed-loop control system that optimizes throughput while maintaining manageable complexity through intelligent decision-making.
2Reliability
If adaptive SNR threshold adjustment is implemented, then communication quality is maintained under fading conditions, but device complexity increases
Solution Approach 1:
The system pre-establishes multiple MODCOD schemes with associated SNR thresholds before transmission begins. These predetermined schemes are stored in lookup tables, allowing the controller to quickly select appropriate parameters without performing complex real-time calculations, thus maintaining reliability while limiting complexity growth.
Solution Approach 2:
The patent adjusts transmission parameters (modulation order, coding rate) based on changing SNR conditions. By dynamically changing these parameters within a predefined set of schemes, the system maintains communication quality under fading conditions without requiring an overly complex adaptive controller.
3Productivity
If continuous SNR monitoring and ACM is implemented, then throughput is maximized under dynamic conditions, but loss of time for processing and adaptation increases
Solution Approach 1:
The system prepares multiple MODCOD schemes and their corresponding SNR thresholds in advance, storing them in lookup tables. This preliminary preparation eliminates the need for complex real-time optimization calculations, allowing rapid adaptation to changing SNR conditions with minimal processing delay, thus maximizing throughput while minimizing adaptation time.
Solution Approach 2:
The patent implements dynamic adaptation where the system continuously monitors SNR and quickly switches between pre-defined MODCOD schemes. This dynamic approach allows the system to respond rapidly to changing channel conditions, maximizing throughput while keeping adaptation time minimal through efficient scheme selection rather than lengthy optimization processes.
Data Source
AI summary
One example includes an ACM transceiver system. An ACM transceiver system includes an ACM controller configured to receive a reported signal-to-noise ratio (SNR) via each of a plurality of return signals corresponding to a respective plurality of transmit signals that were each sequentially previously transmitted from the ACM transceiver system in a respective modulation and coding scheme (MODCOD). The reported SNR via a given one of the plurality of return signals corresponds to the respective one of the plurality of transmit signals. The ACM controller continuously generates an adaptive SNR threshold associated with each of the plurality of MODCODS based on the reported SNR delivered by the received plurality of return signals, and compares the reported SNR with the adaptive SNR threshold of each of the plurality of MODCODS to select one of the plurality of MODCODS for transmission of a next transmit signal.