Variable-Length FEC Block Encoding for Wireless Frame Transport

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Solution Overview

Problem

Current electronic communication systems face inefficiencies in transmitting variable-sized data frames due to the need for fixed-size cell encapsulation, which leads to excessive overhead for small messages and inefficient use of resources, and the selection of Forward Error Correction (FEC) block sizes that vary significantly with message size, affecting Es/No requirements.

Innovation Solution

A family of block encoders with different input block sizes and code rates is defined, allowing for the encoding of MAC frames into sub-blocks of identical bit lengths, which are then aggregated and transmitted in a single RF burst using a constant symbol rate, ensuring consistent Es/No requirements across all encoders, thereby optimizing encapsulation efficiency and reducing the need for fragmentation and excessive padding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If small cell sizes are used for encapsulation, then small messages are transported efficiently, but large messages generate excessive overhead due to fragmentation

Engineering Contradiction:
Improvetransport efficiency for small messagesVSAvoidoverhead for large messages
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent implements dynamic cell size selection where the encapsulation cell size is adjusted based on the actual message size. Small messages use small cells for efficient transport, while large messages are automatically fragmented into multiple cells with appropriate overhead management. This dynamic adaptation resolves the contradiction by optimizing the cell size parameter according to the specific transmission requirements.

Inventive Principle:
Principle #15Dynamics

2Productivity

If large cell sizes are used for encapsulation, then large messages are transported efficiently, but small messages require excessive padding with zeros

Engineering Contradiction:
Improvetransport efficiency for large messagesVSAvoidpadding overhead for small messages
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The system dynamically selects the appropriate cell size based on the message size being transmitted. When small messages need to be transmitted, smaller cell sizes are used to minimize padding requirements. When large messages are transmitted, larger cell sizes are used to improve transport efficiency. This dynamic parameter adjustment eliminates the need for excessive padding while maintaining efficiency for both small and large messages.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If large FEC block sizes are selected, then transmit power requirements are minimized, but small MAC messages require excessive zero padding

Engineering Contradiction:
Improvetransmit power requirementsVSAvoidzero padding for small messages
Core Design Contradiction:
Use of energy by moving objectVSLoss of substance

Solution Approach 1:

The patent implements dynamic FEC block size selection that adapts to the size of the MAC message being transmitted. Small MAC messages are encoded using smaller FEC blocks to minimize padding requirements, while larger messages utilize larger FEC blocks to reduce the padding-to-data ratio and minimize transmit power requirements. This dynamic adaptation resolves the contradiction between power efficiency and padding overhead.

Inventive Principle:
Principle #15Dynamics

4Loss of substance

If small FEC code block sizes are selected, then inefficiency from zero padding is reduced, but more transmit EIRP is required

Engineering Contradiction:
Improveinefficiency from zero paddingVSAvoidtransmit EIRP
Core Design Contradiction:
Loss of substanceVSPower

Solution Approach 1:

The system dynamically adjusts the FEC code block size based on the message size and transmission requirements. For small messages, smaller code blocks are used to minimize padding inefficiency, accepting the higher EIRP requirement. For larger messages, larger code blocks are used to reduce the overall padding ratio and lower the EIRP requirement. This dynamic parameter optimization balances the trade-off between padding efficiency and power consumption.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP1961123B1Variable length data encapsulation and encoding
Publication Date: 2016.12.21 VIASAT INC
  • EP1961123B1 patent drawingFigure 1
  • EP1961123B1 patent drawingFigure 2A
  • EP1961123B1 patent drawingFigure 2B~2C

AI summary

Systems, apparatus, and methods of encoding variable length data for efficient transport over a wireless channel. A wireless terminal can determine a frame size to encode, and can encode and transmit the frame data as one or more encoded blocks selected from a family of block sizes. Each block size can correspond to a particular encoder rate. The frame is parsed into a number of segments having a block size selected from the family of block sizes. The block sizes are selected to maximize the spectral efficiency of the frame. Each segment is then encoded with an encoder corresponding to the block size and having a coding rate that is configured to provide a substantially equal energy per symbol for all of the blocks. The encoded blocks are then aggregated and the smallest block zero padded. The aggregate of encoded blocks can be transported in one or more bursts.