Multipoint Voice Protocol for Ad-Hoc Networks

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Solution Overview

Problem

Traditional wireless network protocols face challenges in maintaining Quality of Service (QoS) in dynamic, multi-hop Ad-Hoc environments due to rapid node mobility and bandwidth restrictions, leading to inefficient routes, excessive bandwidth consumption, and inability to adapt to topological changes, especially in tactical communication systems where centralized control points render networks vulnerable.

Innovation Solution

A protocol utilizing Time Division Multiple Access (TDMA) reservation and Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) contention schemes, combined with link-state based routing, to ensure guaranteed QoS for voice conferencing in mobile, Ad-Hoc networks, eliminating the need for traditional RTS/CTS handshakes and reducing overhead, while allowing for roaming between network nodes without additional control overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional routing protocols are used in mobile Ad-Hoc networks, then routing decisions can be made, but the routes become obsolete quickly due to node mobility and the network requires continuous re-computation causing connection interruptions

Engineering Contradiction:
Improveroute stabilityVSAvoidtime for route re-computation
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-establishing virtual circuits with reserved bandwidth before actual data transmission begins. The circuit setup phase reserves resources in advance, allowing the actual data flow to start immediately without waiting for continuous route re-computation during transmission, thus reducing connection interruptions and improving reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by allowing the virtual circuit topology to adapt dynamically to node mobility. When nodes move or fail, the system can re-route through alternative paths without disrupting the entire network operation, maintaining route stability while accommodating changing network conditions without requiring complete re-computation.

Inventive Principle:
Principle #15Dynamics

2Reliability

If virtual circuit setup with hop-by-hop routing is used, then QoS can be provisioned, but the time and bandwidth required for setting up and maintaining the circuit increases

Engineering Contradiction:
ImproveQoS guaranteeVSAvoidcircuit setup complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the network into hierarchical levels (core network and access network) with different functional responsibilities. The core network handles centralized circuit setup and resource allocation, while access networks handle local routing. This segmentation reduces the complexity at each individual node while maintaining overall QoS guarantees through coordinated operation across segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses an intermediary approach by introducing a core network layer that mediates between access networks and the internet. The core network acts as an intermediary for circuit setup, resource reservation, and QoS management, offloading these complex functions from individual access nodes and simplifying the overall system architecture while maintaining reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If centralized control points are used for network management, then QoS can be coordinated, but the network becomes vulnerable to failures at these control points

Engineering Contradiction:
ImproveQoS coordinationVSAvoidnetwork vulnerability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies segmentation by separating network functions into distinct segments: a core network for centralized QoS coordination and access networks for distributed operation. This segmentation allows centralized control where needed for QoS while maintaining distributed resilience, as failures in access networks do not propagate to the core network and vice versa.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements beforehand cushioning by pre-establishing virtual circuits with reserved bandwidth and multiple alternative paths before actual communication begins. This preparation cushions the network against future failures by having redundant paths ready, ensuring that if a node or link fails, communication can continue through alternative routes without QoS degradation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If RTS/CTS handshakes are used for channel access, then collision avoidance can be achieved, but the overhead and channel access time increase

Engineering Contradiction:
Improvecollision avoidanceVSAvoidchannel access time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by reserving channel access time in advance through virtual circuit setup. Once a virtual circuit is established with reserved bandwidth, the data transmission can proceed directly without requiring repeated RTS/CTS handshakes for each packet, reducing channel access time while maintaining collision avoidance through the pre-reserved time slots.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS7768989B2Method and apparatus for multipoint voice operation in a wireless, Ad-Hoc environment
Publication Date: 2010.08.03 L3HARRIS GLOBAL COMMUNICATIONS INC
  • US7768989B2 patent drawing
  • US7768989B2 patent drawing
  • US7768989B2 patent drawing

AI summary

The present invention protocol offers guaranteed Quality of Service (QoS) for concurrent calls in a highly dynamic, scalable network. The invention employs a TDMA reservation technique to transmit voice traffic to multiple destinations and a CSMA/CA contention scheme to support data traffic. The present invention operates over a link-state based routing protocol that reliably floods routing and resource reservation information to network nodes. The present invention is suitable for general networking applications that require QoS for multimedia traffic in a mobile, Ad-Hoc network and enables conference calls to be established and operated in that type of network under various conditions. Moreover, the present invention capitalizes on certain properties of a radio, such as a RAKE type receiver, that sums up multiple, identical transmissions from multiple sources. In addition, the present invention enables roaming between and/or within a group or island of network nodes during the lifetime of a call.