RLC PDU Reassembly via Segmented Timer Management

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Solution Overview

Problem

The existing methods for receiving and processing data in the radio link control layer, particularly in the new radio (NR) system, face challenges due to the lack of support for service data unit (SDU) concatenation and in-sequence delivery, which complicates the implementation of wireless communication systems.

Innovation Solution

A method and device that process radio link control (RLC) protocol data units (PDUs) based on their sequence numbers (SNs), activating or expiring re-assembly timers to manage the reassembly of complete SDUs, even in the absence of SDU concatenation and in-sequence delivery, by maintaining multiple re-assembly timers and processing PDUs according to their current operating states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple re-assembly timers are maintained to handle segmented SDUs without concatenation, then the system can process RLC PDUs in non-contiguous reception scenarios, but the device complexity increases

Engineering Contradiction:

Improveability to process segmented SDUs without concatenationVSAvoidnumber of re-assembly timers to maintain

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the SDU reassembly process by maintaining multiple independent re-assembly timers, each associated with a specific SDU. This allows the system to handle segmented SDUs independently without requiring concatenation, as each segment can be reassembled with its own timer management. The segmentation principle directly addresses the technical challenge of processing RLC PDUs when SDU concatenation is not supported.

Inventive Principle:

Principle #1Segmentation

2Productivity

If RLC PDUs are processed without in-sequence delivery, then the system can handle out-of-order arrivals, but the reliability of data delivery decreases

Engineering Contradiction:

Improveprocessing speed of out-of-order PDUsVSAvoiddata delivery accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by starting re-assembly timers when the first segment of an SDU is received, and extending them when subsequent segments arrive. This preliminary timing mechanism ensures that all segments are collected within a defined time window before reassembly, maintaining reliability even when PDUs arrive out of sequence. The timer-based approach pre-establishes the reassembly window before all segments are received.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback through re-assembly timer extensions based on segment reception status. When a new SDU segment is received, the system provides feedback by extending the re-assembly timer, ensuring that the timer remains active until all segments are collected. This feedback mechanism maintains data integrity and reliability while allowing flexible out-of-order processing.

Inventive Principle:

Principle #23Feedback

3Reliability

If re-assembly timers are extended for every new SDU segment received, then complete SDUs can be reassembled even with delayed segments, but the loss of time increases due to waiting for all segments

Engineering Contradiction:

Improvecomplete SDU reassembly rateVSAvoidwaiting time for segment collection

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies partial action by extending re-assembly timers only when necessary - specifically, when a new SDU segment is received that requires additional time for collection. The timer is not continuously extended but only when new segments arrive, balancing the need for complete reassembly with minimizing unnecessary waiting time. This selective extension avoids excessive time loss while maintaining reliable reassembly.

Inventive Principle:

Principle #16Partial or excessive action

4Loss of time

If the re-assembly timer is activated for each segmented PDU, then segments can be collected within a defined time window, but the device complexity increases due to timer management

Engineering Contradiction:

Improvetime window for segment collectionVSAvoidtimer activation and management

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent merges timer management operations by combining the activation and extension logic into a unified process. When a new SDU segment is received, the system checks whether the re-assembly timer is already active; if so, it extends the existing timer rather than creating a new one. This merging of timer operations reduces the number of independent timer management tasks while maintaining the defined time window for segment collection.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10873990B2Method and device for receiving and processing data of radio link control layer

Publication Date: 2020.12.22 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

The present application provides a method and a device for receiving and processing data of a radio link control (RLC) layer, where the method includes: receiving a RLC protocol data unit (PDU); when a data field of the target RLC PDU merely comprises a segment of a complete RLC service data unit (SDU), processing the target RLC PDU or discarding the RLC PDU according to a current operating state of a re-assembly timer corresponding to a value of a sequence number (SN) comprised in the target RLC PDU, where the target RLC PDU is one of a plurality of RLC PDUs, the plurality of RLC PDUs has SNs of a same value, and the plurality of RLC PDUs is capable of being re-assembled into the complete RLC SDU, and the current operating state is one of the following operating states: non-activated state, counting state and expired state.