MAC PDU Padding Indicator Using E Field Repurposing

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Solution Overview

Problem

In the Evolved Universal Mobile Telecommunications System (E-UMTS) or Long Term Evolution (LTE) system, the existing methods fail to effectively indicate padding data in MAC PDU, leading to ambiguity in distinguishing different cases of MAC PDU sizes, especially when 1-byte or 2-byte spaces are present, which affects the decoding process at the receiving side.

Innovation Solution

The proposed solution involves using a padding indicator, such as a Padding Extension (PE) field or a 2-bit Padding Indicator (PI), to explicitly indicate the presence and size of padding bytes within the MAC PDU, ensuring accurate representation and decoding of MAC PDU sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing MAC PDU formatting methods are used without padding indicators, then the structure remains simple, but ambiguity arises in distinguishing different cases of MAC PDU sizes especially when 1-byte or 2-byte spaces are present

Engineering Contradiction:
ImproveMAC PDU size indication accuracyVSAvoidMAC PDU header structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses bit value changes in the E field (acting as a padding indicator) to encode different padding scenarios. When E=0, it indicates specific padding cases (1-byte or 2-byte padding), while E=1 indicates no padding. This binary state change allows the receiver to accurately determine MAC PDU size without adding substantial structural complexity.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent changes the interpretation parameter of the existing E field based on the MAC PDU size context. Instead of always treating E as an extension indicator, the system dynamically interprets E as a padding indicator when the MAC PDU size falls within specific ranges (1-2 bytes padding), thereby resolving size ambiguity without adding new fields.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If padding data is not explicitly indicated, then the header structure remains compact, but decoding errors occur at the receiving side due to inability to distinguish different MAC PDU size cases

Engineering Contradiction:
ImproveDecoding accuracyVSAvoidPadding data information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The E field serves as an intermediary indicator that conveys padding information between the transmitter and receiver. By repurposing this existing field as a padding indicator in specific contexts, the system enables accurate decoding without adding separate dedicated padding indicator fields, thus preventing information loss while maintaining efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The padding indicator in the header provides feedback information to the receiver about the actual MAC PDU size structure. This allows the receiver to correctly interpret the payload length and avoid decoding errors, ensuring reliable data extraction even when padding is present.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If additional padding indicator fields are added to MAC PDU, then decoding accuracy improves, but radio resource efficiency decreases due to increased overhead

Engineering Contradiction:
ImprovePadding size indicationVSAvoidRadio resource utilization efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The E field performs multiple functions: it serves as both an extension indicator for MAC subheaders and as a padding indicator when MAC PDU size requires it. This multi-functionality eliminates the need for separate dedicated padding indicator fields, maintaining radio resource efficiency while providing accurate padding size indication.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the padding indication function with the existing E field structure. By combining multiple functions (extension indication and padding indication) into a single field through context-dependent interpretation, the system avoids increasing header overhead while achieving precise padding size indication.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2181540B1Effective data block transmission method using header indicator
Publication Date: 2017.12.06 LG ELECTRONICS INC
  • EP2181540B1 patent drawingFigure 1~3
  • EP2181540B1 patent drawingFigure 4~7(b)
  • EP2181540B1 patent drawingFigure 8(a)~10(c)

AI summary

Disclosed is a radio (wireless) communication system providing a radio communication service and a terminal, and more particularly, to a method of exchanging a data block or data unit between a base station and a terminal in an Evolved Universal Mobile Telecommunications System (E-UMTS) that has evolved from a Universal Mobile Telecommunications System (UMTS) or a Long Term Evolution (LTE) system, which can generate a data block to enhance efficiency of radio resources.