RLC Layer Out-of-Order Delivery for LTE Latency

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Solution Overview

Problem

Current wireless communication systems, particularly in LTE and EN-DC configurations, face challenges in optimizing latency and throughput due to the requirement for in-order data packet delivery, which can lead to increased latency and processing overhead, especially when dealing with out-of-sequence data packets.

Innovation Solution

Implementing a configuration message that allows for out-of-order delivery of data units from lower layers to upper layers in the protocol stack, specifically configuring the RLC layer to bypass in-order delivery guarantees, enabling efficient data packet transmission by allowing out-of-order delivery in EN-DC and LTE DC configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If in-order delivery guarantee is implemented in the RLC layer, then data transmission reliability is improved, but latency increases and throughput decreases

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidlatency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent dynamically adjusts the delivery order configuration based on network conditions and traffic types. The RLC layer can switch between in-order and out-of-order delivery modes, allowing the system to optimize for reliability when needed and for low latency when needed, making the delivery mechanism adaptive rather than static

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the delivery parameter (in-order vs out-of-order) as a configurable option. By modifying this parameter based on specific network conditions and application requirements, the system can achieve both high reliability and low latency in different scenarios, resolving the contradiction through parameter optimization

Inventive Principle:
Principle #35Parameter changes

2Reliability

If in-order delivery guarantee is implemented in the RLC layer, then data transmission reliability is improved, but processing overhead increases

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidprocessing overhead
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic configuration where the RLC layer can adapt its processing behavior based on traffic requirements. For delay-sensitive or high-priority traffic, out-of-order delivery is enabled to reduce processing overhead, while for reliability-critical traffic, in-order delivery is maintained

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The delivery order parameter is changed from a fixed setting to a configurable parameter that can be adjusted based on traffic type and network conditions. This allows the system to optimize processing overhead by selecting appropriate delivery modes for different data flows

Inventive Principle:
Principle #35Parameter changes

3Productivity

If out-of-order delivery is enabled, then latency is reduced and throughput is enhanced, but data transmission reliability may be compromised

Engineering Contradiction:
ImprovethroughputVSAvoiddata transmission reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent enables dynamic switching between delivery modes based on real-time network conditions and application requirements. The system can transition from in-order to out-of-order delivery when throughput optimization is needed, and revert when reliability becomes the priority

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies different delivery order configurations to different data flows or bearers based on their specific requirements. Critical data flows can maintain in-order delivery for reliability, while non-critical flows can use out-of-order delivery for enhanced throughput, achieving local optimization rather than a global one-size-fits-all approach

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3777469B1Enhancing latency and throughput in LTE and in an asymmetric en-DC configuration
Publication Date: 2024.07.03 APPLE INC
  • EP3777469B1 patent drawingFigure 1~2
  • EP3777469B1 patent drawingFigure 3
  • EP3777469B1 patent drawingFigure 4

AI summary

Apparatuses, systems, and methods for a wireless device to perform a method including a user equipment device (UE) receiving from a network entity, a configuration message, wherein the configuration message includes a parameter specifying out-of-order delivery of data units from lower layers to upper layers of a protocol stack implemented on the UE, configuring a radio link control (RLC) layer of a protocol stack for out-of-order delivery based on the received configuration message, and notifying the network entity of the configuration of the RLC layer.