Effects of the Wireless Channel, Signal Compression and Network Architecture on Speech Quality in Voip Networks

Abstract

Voice over Internet Protocol (VoIP) telephony is an emerging technology slowly finding its way into military applications. It provides several advantages over PSTN but comes short on performance, quality of service and availability. The purpose of this thesis is to measure the quality of voice in VoIP communications. More specifically it investigates the effects of wireless channel conditions as well as channel coding and compression on the received speech quality. Both simulation and experimentation are conducted using Matlab code and Speex software and across commercial VoIP networks. Simulation shows that fading channel parameters can heavily affect the quality of received speech. Speech compression results in bit rate gain, but, on the other hand, the signal becomes more sensitive to errors. The performance of an outdoor wireless network is better than that of an indoor network. The VoIP network architecture can affect the received speech quality on a long-distance connection.

Document Details

• Document Type: Technical Report
• Publication Date: Jun 01, 2007
• Accession Number: ADA473528

Entities

People

• Tiantioukas Nikolaos

Organizations

• Naval Postgraduate School

Tags

Communities of Interest

• Biomedical
• Cyber
• Energy and Power Technologies
• Space

DTIC Thesaurus Topics

• Communication Channels
• Communication Systems
• Computer Networks
• Data Links
• Data Transmission
• Digital Communications
• Modulation
• Multiple Access
• Network Architecture
• Network Protocols
• Orthogonal Frequency Division Multiplexing
• Speech Compression
• Transport Protocols
• Voice Communications
• Voice Over Internet Protocol
• Wireless Communications
• Wireless Networks

Fields of Study

• Computer science
• Engineering

Readers

• Computer Networking
• Radio communications and signal processing.
• Speech Processing/Speech Recognition.