De-jitter Buffer for Circuit Switched Voice Over HSPA Networks

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Solution Overview

Problem

High Speed Packet Access (HSPA) communication systems face challenges in efficiently and robustly transmitting circuit-switched voice over packet-switched networks, particularly due to jitter issues caused by hybrid automatic repeat request (HARQ) protocols, which affect voice quality and data transmission reliability.

Innovation Solution

The implementation of a de-jitter buffer with a fixed delay component and adaptive delay component in the radio network controller, which delays packets based on HARQ transmission intervals and queuing delays to mitigate jitter, ensuring consistent packet delivery and maintaining voice quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If HSPA communication systems transmit circuit-switched voice over packet-switched networks using HARQ protocols, then data transmission speed and efficiency are improved, but jitter is introduced that degrades voice quality and transmission reliability

Engineering Contradiction:
Improvedata transmission speedVSAvoidvoice transmission reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by implementing a de-jitter buffer that proactively compensates for HARQ-induced jitter before voice packets are delivered to the core network. The buffer pre-calculates and applies delay adjustments based on expected HARQ transmission intervals, ensuring voice quality is maintained without sacrificing data transmission speed. This resolves the contradiction by preparing compensation measures in advance rather than reacting to jitter after it occurs.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If packets are delayed to mitigate jitter, then voice quality is improved, but transmission latency increases

Engineering Contradiction:
Improvevoice qualityVSAvoidtransmission latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies dynamics by implementing an adaptive delay mechanism in the de-jitter buffer that dynamically adjusts packet delays based on actual HARQ transmission conditions and network status. Rather than applying fixed delays, the system continuously monitors jitter patterns and modifies delay parameters in real-time, optimizing the balance between voice quality improvement and latency minimization. This resolves the contradiction by making the delay adaptive rather than static.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by modifying packet delay parameters based on HARQ transmission intervals and network conditions. The de-jitter buffer adjusts timing parameters dynamically to compensate for jitter while minimizing overall latency. By changing delay parameters adaptively rather than using fixed values, the system improves voice quality without imposing excessive latency penalties.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a de-jitter buffer is implemented to reduce jitter, then voice quality is improved, but device complexity increases

Engineering Contradiction:
Improvevoice qualityVSAvoidnetwork controller complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the intermediary principle by introducing a de-jitter buffer as a mediator component between the packet-switched network interface and the circuit-switched voice core network. This intermediary buffer absorbs and compensates for jitter without requiring complex modifications to the existing HARQ protocol or core network infrastructure. By isolating the jitter compensation function in a dedicated intermediary component, the system improves voice quality while minimizing overall device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2186248B1Method and apparatus for transmission of circuit switched voice over packet switched networks
Publication Date: 2014.03.26 QUALCOMM INC
  • EP2186248B1 patent drawingFigure 1
  • EP2186248B1 patent drawingFigure 2
  • EP2186248B1 patent drawingFigure 3

AI summary

Systems and methodologies are described that facilitate and/or effectuate transmission of circuit switched voice over packet switched networks. The systems and methodologies provide for the receiving a first packet originating from access terminals and/or user equipment, determining within which hybrid automatic repeat request (HARQ) the first packet is received, ascertaining an amount of delay that is applied to the first packet before the first packet is forwarded into a core circuit switched network; and establishing a periodic time interval within which to convey subsequent packets that originate from the communicating access terminal and/or user equipment.