Network Node TTI Bundling for VoIP QoS

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Solution Overview

Problem

In wireless communication networks, cell-edge devices experience high pathloss, leading to increased packet delay and resource consumption due to extensive retransmissions of VoIP voice frames, which degrade voice quality for other devices and increase control channel load, while existing solutions like TTI bundling are inefficient and resource-intensive.

Innovation Solution

A network node method that determines aggregated QoS requirements and achievable bitrate using TTI bundling, enabling TTI bundling only when necessary and feasible to maintain service-specific QoS requirements, ensuring efficient resource allocation and prioritizing high-priority services.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If TTI bundling is enabled for cell-edge devices to improve voice frame transmission reliability, then transmission success probability increases, but system resources are consumed and voice quality for other devices deteriorates

Engineering Contradiction:
Improvetransmission success probabilityVSAvoidsystem resource consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent dynamically changes the TTI bundling configuration parameter based on channel quality measurements. When channel quality falls below a threshold, TTI bundling is enabled; when it improves above the threshold, TTI bundling is disabled. This parameter change resolves the contradiction by enabling reliable transmission only when necessary, rather than continuously consuming system resources.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic switching of TTI bundling mode based on real-time channel conditions. The network node monitors channel quality and adjusts the TTI bundling configuration accordingly, transitioning between enabled and disabled states. This dynamic approach ensures transmission reliability when needed while conserving system resources when channel conditions are good.

Inventive Principle:
Principle #15Dynamics

2Reliability

If voice frames are segmented into multiple segments to improve transmission reliability, then transmission success probability increases, but header overhead increases and link efficiency decreases

Engineering Contradiction:
Improvetransmission success probabilityVSAvoidheader overhead
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of always segmenting voice frames (excessive action), the patent applies segmentation only when channel quality falls below a predetermined threshold (partial action). This selective approach maintains transmission reliability when needed while avoiding unnecessary header overhead and link efficiency degradation when channel conditions are sufficient.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If retransmissions are performed to ensure full speech frame delivery, then transmission reliability improves, but packet delay increases

Engineering Contradiction:
Improvedelivery reliabilityVSAvoidpacket delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary action by enabling TTI bundling proactively when channel quality deteriorates below a threshold, preventing transmission failures before they occur. This is contrasted with reactive retransmission approaches that must wait for failed transmissions to occur first. By taking preliminary preventive action, the system ensures reliable delivery without the delay penalties associated with retransmissions.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3278616B1A network node and method performed thereby for supporting VOIP service of wireless device
Publication Date: 2020.07.22 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3278616B1 patent drawingFigure 1a~1b
  • EP3278616B1 patent drawingFigure 1c~1d
  • EP3278616B1 patent drawingFigure 1e~1f

AI summary

A network node and a method performed thereby for supporting VoIP service of a wireless device are provided. The network node is operable in a wireless communication network, and the method comprises, when a channel quality of a channel between the wireless device and the network node falls below a predetermined threshold: determining (110) QoS requirements with regard to GBR for services which the wireless device is currently using; determining (120) an achievable bitrate using TTI bundling; and determining (150) to enable TTI bundling of the wireless device based on the determined aggregated GBR requirement and the determined achievable bitrate.