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Wide band speech introduction into VoIP solutions 9th June 2004

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

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  1. Wide band speech introduction into VoIP solutions9th June 2004 Gilbert DERVAL, Yannick MAHIEUX, D. DELEAM France Télécom - R&D Division

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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, …)

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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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