Opportunistic Transport Protocol for Ad Hoc Network Data

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Solution Overview

Problem

Ad hoc wireless networks face challenges in efficiently transporting real-time data streams like VoIP and IPTV due to high variability in radio conditions and competition for the communication medium, leading to packet loss and delay, which conventional protocols like TCP cannot effectively address.

Innovation Solution

A method where data is transmitted as self-sufficient messages split into packets, with each node measuring real-time stream quality and authorizing transmission based on threshold values, using an opportunistic protocol that adapts transmission decisions hop by hop, ensuring protection of critical flows by managing packet transmission and retransmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional TCP protocol is used for data transport in ad hoc networks, then data transmission reliability is improved, but real-time stream quality deteriorates due to added delay and packet loss

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidreal-time stream delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the network traffic into different priority categories (real-time streams vs. data streams). Each category is handled by different transport mechanisms: real-time streams use guaranteed quality transport while data streams use best-effort transport. This segmentation allows TCP reliability mechanisms to be applied selectively without affecting real-time performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different quality of service treatments to different types of traffic at each node in the network. Intermediate nodes identify real-time streams and provide them with priority handling, while data streams receive standard handling. This local quality differentiation protects real-time streams from TCP-induced delays and packet loss while maintaining data transmission reliability where applicable.

Inventive Principle:
Principle #3Local quality

2Reliability

If TCP protocol is used in ad hoc networks, then data transport reliability is improved, but competition for communication medium increases causing packet loss

Engineering Contradiction:
Improvedata transport reliabilityVSAvoidIP congestion and packet loss
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful congestion control mechanisms from TCP and replaces them with a selective transport approach. Data streams use TCP with modified behavior, while real-time streams use a dedicated transport mechanism that bypasses TCP's congestion control. This extraction removes the source of harmful competition for the communication medium while preserving data transport reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary mechanism at intermediate nodes that identifies and separates real-time streams from data streams. This intermediary applies different transport policies: allowing data streams to use TCP while protecting real-time streams through priority scheduling and resource reservation. The intermediary prevents TCP-induced congestion from affecting real-time traffic.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If conventional QoS mechanisms are used, then local queue management is improved, but global network awareness of traffic competition is insufficient

Engineering Contradiction:
Improvequeue managementVSAvoidglobal traffic awareness
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent implements a feedback mechanism where intermediate nodes monitor the network environment and adjust their queue management policies accordingly. Nodes detect the presence of real-time streams and feedback this information to modify transmission behavior. This global awareness allows the network to adaptively protect real-time streams while maintaining efficient queue management at each node.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2225901B1Transport of priority data in an ad-hoc network
Publication Date: 2012.02.01 THALES SA
  • EP2225901B1 patent drawingFigure 1~2

AI summary

The invention relates to a device and a method for conveying data flows in a network that comprises a plurality of nodes in a given configuration and at a given moment. The device includes: a database (12) storing the message(s) to be transmitted; a congestion control module (20) connected to said database; a scheduler having as inputs the messages stored in the database, the route determined for a message by a routing table (13) and a neighbouring node table (14), and a piece of information from a receiving module (19); a module including an opportunist transport protocol (16) receiving information from the scheduler (15) and from a measuring module (17), said opportunist transport protocol being adapted to split a message to be transmitted into N packets Pi, and transmitting said packets to the network layer of said node; and a module (18) capable of deciding whether the current node is capable of accepting an incoming handover of a message.