Real-time Data Transport Protocol for Wireless Mesh Voice

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Solution Overview

Problem

Wireless mesh networks face challenges in supporting voice sessions due to high error rates and latency, as voice codecs are optimized for reliable wired networks and struggle with sequential packet loss, leading to congestion and degraded network capacity.

Innovation Solution

Implementing a real-time data transport protocol that aggregates multiple packets using a sliding window and transmits redundant copies, allowing intermediate nodes to pass error-prone voice packets up the protocol stack, and using forward error correction to ensure reliable delivery of voice and video streams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If voice codecs are optimized for reliable wired networks, then coding efficiency is improved, but adaptability to wireless mesh networks deteriorates

Engineering Contradiction:

Improvecoding efficiencyVSAvoidadaptability to wireless mesh networks

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the fundamental parameters of packet transmission by implementing a real-time transport protocol that aggregates multiple voice packets into single transmission units. This transforms the transmission approach from individual packet-level optimization to session-level optimization, enabling the system to adapt to wireless mesh network conditions while maintaining coding efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a real-time transport protocol as an intermediary layer between the voice codec and the wireless mesh network. This intermediary aggregates packets, manages redundancy, and handles error correction, thereby decoupling the codec from network-specific optimizations and enabling universal adaptability across different network types.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If packets are transmitted individually with retry mechanisms, then reliability is improved, but latency increases

Engineering Contradiction:

Improvepacket delivery reliabilityVSAvoidlatency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent merges multiple individual packet transmissions into a single aggregated transmission unit. By combining multiple voice packets into one real-time transport protocol packet, the system reduces the number of individual transmission attempts and eliminates repeated latency accumulation from multiple retry cycles, thereby reducing overall latency while maintaining reliability through redundancy within the aggregated packet.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements preliminary error correction by including redundant copies of voice packets within the aggregated transmission. This forward error correction approach prepares backup data in advance, allowing the receiving end to recover from packet loss without requiring retry transmissions, thus preventing latency accumulation from repeated retransmission attempts.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If retry mechanisms are implemented at each hop, then packet delivery is improved, but network capacity deteriorates

Engineering Contradiction:

Improvepacket deliveryVSAvoidnetwork capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent extracts the error correction and redundancy functions from the individual packet transmission layer and consolidates them at the real-time transport protocol layer. By taking out the retry mechanism from each hop and implementing it at the session level through aggregated packet transmission, the system eliminates the multiplying effect of repeated transmissions across multiple hops, thereby preserving network capacity while maintaining packet delivery reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If redundant copies of packets are transmitted, then reliability is improved, but bandwidth consumption increases

Engineering Contradiction:

Improvepacket delivery reliabilityVSAvoidbandwidth consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies partial redundancy by including only the necessary number of redundant copies within the aggregated packet, rather than transmitting every possible packet multiple times. The real-time transport protocol calculates the optimal redundancy level based on the number of aggregated packets and network conditions, providing sufficient error correction with minimal additional bandwidth consumption.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7729328B2Real-time sessions for wireless mesh networks

Publication Date: 2010.06.01 CISCO TECHNOLOGY INC

AI summary

A real-time data transport protocol directed to aggregating multiple packets of a real-time protocol session and transmitting redundant copies of the packets as defined by a sliding window. In particular implementations, a method comprising accessing a plurality of packets of a real-time protocol session; aggregating, over a sliding window, a contiguous sequence of packets in the plurality of packets into real-time data transport packets, and transmitting the real-time data transport packets to a receiving node.