Wide band speech introduction into voip solutions 9th june 2004
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Wide band speech introduction into VoIP solutions 9th June 2004. Gilbert DERVAL, Yannick MAHIEUX, D. DELEAM France Télécom - R&D Division. VoIP : an opportunity for Wide band. Packets switching networks offer bit rate versatility Wide bandwith links are available, even in access networks

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Wide band speech introduction into voip solutions 9th june 2004

Wide band speech introduction into VoIP solutions9th June 2004

Gilbert DERVAL, Yannick MAHIEUX, D. DELEAM

France Télécom - R&D Division


Voip an opportunity for wide band
VoIP : an opportunity for Wide band

  • Packets switching networks offer bit rate versatility

  • Wide bandwith links are available, even in access networks

  • IP services integration enables heterogeneous solutions

  • IP terminals become more and more intelligent

    • Embedded codecs and signal processing


What are the success conditions
What are the success conditions?

  • Limited impact on installed infrastructure

    • Network

    • Services platforms

    • Terminals

  • Interoperability with existing solutions

  • Short term availability

  • Clear IPR situation

    • Simplicity

    • Low cost


Limited impact on network infastructure
Limited impact on network infastructure

  • Low bit rate increase

  • No need of additionnal signalling channels

  • Adaptability to traffic conditions

  • Versatility when faced with different access networks


Low impact on service platforms wide band narrow band interoperability
Low impact on service platformsWide band / narrow band interoperability

  • No additionnal function in the call control equipment : VoIP protocols implement codec negotiation

  • No additionnal transcoder in gateways

  • Wide band messages on voice mail equally available from a wide band or a narrow band terminal


Limited impact on terminals 1
Limited impact on terminals (1)

  • The simplest case : reuse of POTS

    • Transducers (earpiece, open listening speaker) weak bandwith  frequency compensation for low frequencies (<300 Hz) and high frequencies (>3400 Hz)

    • Need of an external box such as a Home Gateway including the software (codec, VoIP protocols, RTP/UDP/IP stack, …)

  • Softphones in PC : no problem

    • Multimedia equipment provides wide bandwith

    • Powerfull processors allow software implementation of complex algorithms (codecs, echo cancellation, …)


Limited impact on terminals 2
Limited impact on terminals (2)

  • Wide band IPphones :a specific design

    • Transducers need to be chosen with care (bandwith, dimensions,…)

    • Acoustic design has to be careful, specially for handsfree features (mechanic vibrations, acoustic coupling, echo cancellation)

  • One example : France Telecom / ADTech SI-171


Limited impact on terminals 3
Limited impact on terminals (3)

  • Wireless terminals

    • The same issues as the IPphones (tranducers, acoustics, …),

      • but made more difficult by the small terminal size

    • Additionnal issues due to the wireless link bitrate

      • WiFi : OK, no bandwith problem

      • Bluetooth : still under investigation (no defined codec)

      • DECT : not impossible but difficult (no R&D investment)

  • Mobile phones

    • Wide band available in UMTS Release 5 in packet mode as in circuit mode

    • First wide band mobile phones available Q4 2004 / Q1 2005

    • Same bit rate as nowadays mobile phones : 12.65 kbps

  • CPU issues

    • Single processor architecture

    • Embedded applications (video, data)

    • Wide band must have memory and CPU reasonable requirements


Ipr keep it simple and low cost
IPR : keep it simple and low cost

  • Short time to market

    • simple IPR licensing

      • if possible, a single negotiating partner

    • no long and costly negotiations

  • Cost reduction

    • as few additionnal licences as possible

    • If possible, pay only the extra charge due to the changeover from narrow band to wide band


A structuring component the codec
A structuring component : the codec

  • The codec choice impacts the whole of the above issues

    • Bit rate in the network

    • Versatility when faced with different access networks

    • Versatility in case of network traffic problems

    • Wide band / narrow band interoperability

    • Transcoder need on VoIP services platform (Gateway, voice mail server, …)

    • Terminals (memory, CPU)

    • IPR

    • Audio quality


One solution a scalable codec
One solution : a scalable codec

  • Two parts in the bitstream :

    • A narrow band core compliant to G.729

    • A wide band additionnal part

  • A wide bit rate range

    • Byte level granularity for packets filling optimization

    • Wide band minimum bit rate at least from 14 kbps

    • Same audio quality as G.722 for higher bit rates

  • Dynamic bit rate variation without additionnal signalling

  • A standardized narrow band core G.729 codec

    • Lower cost and simplified IPR situation

    • Wide band G.729 extension

  • An ITU-T action is currently under discussion


Conclusion let s do it asap
Conclusion : let's do it ASAP

  • VoIP is currently in a phase of fast expansion

  • Wide band can increase VoIP attactiveness

  • Once the deployed terminal base too large, it will be more difficult to integrate evolutions

  • So, it's necessary to be fast


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