Predictive Link Planning for Adaptive Coding Without Return Links
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Solution Overview
Problem
Existing wireless communication systems face challenges in performing adaptive coding and modulation (ACM) without a return link from the receiver to the transmitter, as this is impractical in one-way communication links or situations where signal detection is to be minimized.
Innovation Solution
The system employs predictive link planning by determining the link geometry and channel impairments between the transmitter and receiver, predicting signal-to-noise ratios (SNRs), and storing these parameters in a lookup table for retrieval during data transmission, thus enabling ACM without a return link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a return link is added to provide channel state information from receiver to transmitter, then adaptive coding and modulation can be performed, but device complexity and cost increase due to additional hardware
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing channel parameters in lookup tables before actual communication occurs. The transmitter determines channel conditions, link geometry, and impairments in advance, then stores optimal channel parameters for different conditions. During communication, the transmitter simply retrieves parameters from the lookup table based on current conditions, eliminating the need for real-time return link feedback while maintaining adaptive coding and modulation capability.
2Adaptability or versatility
If a return link is added to enable channel state information feedback, then link adaptation can be achieved, but the probability of signal detection increases which is undesirable for low-probability-of-detection applications
Solution Approach 1:
The patent eliminates the need for a return link by performing all channel assessments and parameter selections in advance at the transmitter. The transmitter determines link geometry, calculates channel impairments, predicts signal-to-noise ratios, and stores optimal parameters before communication begins. This open-loop approach provides link adaptation without requiring any feedback transmission, thereby maintaining low probability of detection.
3Adaptability or versatility
If a return link is added for channel state information feedback, then closed loop ACM can be implemented, but loss of time occurs due to the feedback delay
Solution Approach 1:
The patent eliminates feedback delay by performing all channel assessments and parameter selections in advance at the transmitter without requiring receiver feedback. The transmitter determines channel conditions, calculates optimal parameters, and stores them in lookup tables before communication occurs. This open-loop approach provides adaptability without the time loss associated with closed-loop feedback mechanisms.
4Adaptability or versatility
If return link hardware is added to a telemetry or sensor link, then channel state information can be received, but cost, size, weight, and power requirements increase
Solution Approach 1:
The patent extracts and eliminates the return link receiver hardware from the transmitter by moving all channel state information gathering functions to the receiver side. The receiver determines channel conditions and sends only data transmissions, while the transmitter uses open-loop methods to assess channel quality and select parameters. This removes the need for additional receivers, low-noise amplifiers, and diplexers at the transmitter, reducing cost, size, weight, and power.
5Adaptability or versatility
If return link hardware is added to a telemetry or sensor link, then channel state information can be received, but cost, size, weight, and power requirements increase
Solution Approach 1:
The patent extracts and eliminates the return link receiver hardware from the transmitter by moving all channel state information gathering functions to the receiver side. The receiver determines channel conditions and sends only data transmissions, while the transmitter uses open-loop methods to assess channel quality and select parameters. This removes the need for additional receivers, low-noise amplifiers, and diplexers at the transmitter, simplifying manufacturing and reducing implementation complexity.
Data Source
AI summary
A method of transmitting data from a transmitting terminal to a receiving terminal over a channel is provided in which a series of locations for each of the receiving terminals is determined. The method further includes the steps of determining a link geometry of the channel between the transmitting terminal and the receiving terminal for each location in the series of locations, wherein determining the link geometry comprises determining a distance between the transmitting and receiving terminals for each location in the series of locations; determining channel impairments for the link geometries; predicting signal-to-noise ratios (SNRs) of the channel for the link geometries and the channel impairments; storing channel parameters based on the predicted SNRs in a lookup table; retrieving the channel parameters from the lookup table using the distance between the transmitting and receiving terminals; and transmitting data from the transmitting terminal using the channel parameters.