ACARS Message Compression via Radix Encoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The Aircraft Communications, Addressing, and Reporting System (ACARS) messaging format includes significant fixed elements that occupy bandwidth, even though they vary minimally across messages from a common source aircraft, leading to inefficient data transmission.
Innovation Solution
A dynamic compression system for ACARS messages that removes fixed markers and binary encodes variable fields, using radix-base compression for both header/trailer and text payloads, allowing for efficient transmission by selecting an appropriate radix base based on the message content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fixed elements are included in ACARS message structure, then message format standardization is maintained, but bandwidth efficiency deteriorates
Solution Approach 1:
The patent extracts fixed elements (such as address fields, message type indicators, and protocol headers) from the ACARS message structure and transmits them separately or omits them in subsequent messages. Only the variable payload portions are transmitted in full, while fixed elements are inferred or reused from previous transmissions, thereby reducing redundant bandwidth consumption while maintaining message format standardization.
Solution Approach 2:
The patent applies differential compression where different parts of the message are handled differently. Fixed portions of the message structure are compressed or omitted, while variable portions are transmitted in full. This local quality approach allows the system to maintain standardization where needed while optimizing bandwidth efficiency in redundant areas.
2Loss of energy
If message compression is applied, then bandwidth efficiency is improved, but message complexity increases
Solution Approach 1:
The patent segments the ACARS message into fixed elements and variable elements. The compression system processes these segments differently, applying simple compression rules to fixed portions and transmitting variable portions unchanged. This segmentation reduces the complexity of the compression algorithm while maintaining bandwidth efficiency.
Solution Approach 2:
The patent changes the representation parameters of fixed message elements by using differential encoding, where instead of transmitting the full fixed elements repeatedly, the system transmits only the changes or offsets from a reference message. This parameter change approach simplifies the compression logic while achieving bandwidth savings.
3Loss of energy
If fixed markers are removed for compression, then bandwidth usage is reduced, but message reliability may deteriorate
Solution Approach 1:
The patent performs preliminary actions by establishing a reference message containing all fixed elements before compression. The receiving system uses this reference to reconstruct the complete message from the compressed transmission. This preliminary setup ensures that even though fixed markers are removed from subsequent transmissions, message reliability is maintained through the reference framework.
Solution Approach 2:
The patent implements feedback mechanisms where the receiving system sends acknowledgments and requests for retransmission of any missing or corrupted fixed elements. This feedback loop ensures message integrity is maintained even when fixed markers are compressed or omitted, as any transmission errors can be detected and corrected through the feedback channel.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An Aircraft Communication and Addressing Reporting System (ACARS) compatible transmitter is disclosed. In embodiments, the transmitter receives (602) outbound (e.g., downlink or uplink) ACARS messages from aircraft end systems and compresses the header/trailer (H/T) and/or text payloads of ACARS blocks (e.g., text messages) or ACARS acknowledgements (ACK)) prior to transmission. For example, the transmitter compresses ACARS blocks by removing fixed markers and encoding variable fields. The transmitter parses incoming text payloads to determine their character distribution and selects a radix alphabet including the ASCII characters used in the text payload. The transmitter converts the ASCII characters to binary characters of the corresponding alphabet based on the selected radix base, assembling a compressed message block for transmission based on the compressed H/T component and/or text payload, adding a link layer header to indicate the selected radix base to the ACARS destination for decompression of the received compressed message.