André Wolf

Date of Award

3-22-2012

Document Type

Thesis

Degree Name

Master of Science in Electrical Engineering

Department

Department of Electrical and Computer Engineering

First Advisor

Barry E. Mullins, PhD.

Abstract

Mobile ad hoc networks (MANETs) have grown in popularity over the past decade and are increasingly considered for time-sensitive multimedia applications. The impact of various routing protocols on voice traffic using different IEEE 802.11 extensions has been investigated via analytical models, simulations and experimental test beds. Many studies determined that optimized link state routing (OLSR) is a suitable routing protocol to support voice over internet protocol (VoIP) conversations. This research expands upon this understanding by determining the point at which voice traffic is no longer feasible in an ad hoc environment and determines which audio codec is best suited for MANETS. The MANET simulation environment is established using OPNET. Varying combinations of workloads are submitted to the MANET to capture voice performance within a stressed environment. Performance metrics are compared against established benchmarks to determine if thresholds for unacceptable voice quality are exceeded. Performance analysis reveals that VoIP communication using G.711 is not sustainable at walking (1.5 m/s) or jogging (2.5 m/s) speeds when three simultaneous streams are used. Also, G.729a is determined to be the best suited codec for MANETs since it significantly outperforms the other codecs in terms of packet loss and end-to-end delay.

AFIT Designator

AFIT-GE-ENG-12-44

DTIC Accession Number

ADA556301

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