Apic vocoder task group overview l.jpg
Sponsored Links
This presentation is the property of its rightful owner.
1 / 12

APIC Vocoder Task Group Overview PowerPoint PPT Presentation


  • 280 Views
  • Uploaded on
  • Presentation posted in: General

APIC Vocoder Task Group Overview. Project 25 Steering Committee Meeting Special Session April 25, 2008 Ernest Hofmeister, Chair Vocoder Task Group. TIA. Project 25/34 Steering Committee. APIC. Private Radio Section. TR8. Project 25/34 Steering Committee Subgroups

Download Presentation

APIC Vocoder Task Group Overview

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


APIC Vocoder Task Group Overview

Project 25 Steering Committee Meeting

Special Session

April 25, 2008

Ernest Hofmeister, Chair Vocoder Task Group


TIA

Project 25/34 Steering Committee

APIC

Private Radio Section

TR8

Project 25/34 Steering Committee Subgroups

(e.g., P25 & P34 User Needs Subcommittees)

APIC

Subgroups

(e.g., Task Groups, Working Groups)

TIA TR-8 Subgroups

(e.g., Subcommittees)

Vocoder Task Group (and TR-8.4 Vocoder subcmte) Location in TIA TR-8 & P25 Structure

TR-8.4 Vocoder subcmte

Vocoder Task Group


Early Vocoder Work ~1991-1999

  • Project 25 RFP and Proposals for Low Rate Vocoder

  • Mean Opinion Score (MOS) Tests and Evaluation

  • Selection of DVSI IMBE Vocoder (now Baseline Full Rate)

  • TIA Standardization

    • ANSI/TIA/EIA 102.BABA, Project 25 Vocoder Description, May 1998.

    • ANSI/TIA/EIA 102.BABB, Project 25 Vocoder Mean Opinion Score Conformance Test, May 1999.

    • ANSI/TIA/EIA 102.BABC, Project 25 Vocoder Reference Test, April 1999.


DVSI Vocoder Evaluation Results

Original P25 IMBE @ 4.4 kbps--MOS ~ 3.4

Recent Voice Quality vs Bit Rate

Source: DVSI Website

Excerpt Com-Net Ericsson Contribution, Hofmeister, TR-8.12, Mesa, Jan 2001


Recent Vocoder Work 2003-2008 (1)

  • P25 Vocoder for P25 Phase 2 TDMA

  • DAQ vs BER Information for TIA TR-8.18, TSB-88

  • Cognizant of Technical Work and Relevant Technical Contributions Related to IAFC Digital Working Group


Recent Vocoder Work 2003-2008 (2)

  • P25 Vocoder for P25 Phase 2 TDMA

    • MOS (Mean Opinion Score) Voice Quality Testing—03-05

      • DVSI Original Baseline Full Rate IMBE(BFR), Enhanced Full Rate (EFR), and Enhanced Half-Rate (EHR)

      • Experiment 1 – MOS vs Radio Channel Models

      • Experiment 2 – MOS vs Selected Moderate Background Noise

      • Exp 1 & 2 Results Published in TIA TSB-102.BABE

      • Experiment 3 – ITS MOS vs Selected High Background Noises

      • Ex 3 Results Published in TIA TSB-102.BABF

    • Enhanced DVSI Half-Rate Vocoder Recommended to P25 Steering Committee for P25 Ph 2 TDMA as Part of Dual-Rate Vocoder—Jan 2006 (re-affirmed Jan 2007)


Recent Vocoder Work 2003-2008 (3)

  • P25 Vocoder for P25 Phase 2 TDMA--cont

    • (P25 Steering Committee Adopted Recommendation – April 2007)

    • (P25 Steering Committee Adopted Enhanced DVSI Full-Rate Vocoder as New Baseline for P25 Phase 1 Going Forward – Oct 2005 (re-affirmed Jan 2008))

    • P25 Vocoder Standardization Regarding Enhanced Capability

      • First “Prong”--Developing P25 Half-Rate Vocoder Annex (Interoperability) Standard to Compliment Existing Vocoder Stnds

        • Comment Resolution Completed and Accepted by VTG

      • Second “Prong”--Developing Audio, Quality Rqmt & Verif Test

        • Voice Quality Performance Requirement to Assure Performance Statistically Equivalent to or Better than the Enhanced Vocoder Performance Documented in TSB-102.BABE

        • Test Method to Assure Compliance to Voice Quality Performance Requirement


Recent Vocoder Work 2003-2008 (4)

  • DAQ vs BER Information for TIA TR-8.18, TSB-88

    • DAQ - Delivered Audio Quality

    • BER – Bit Error Rate

    • For TSB-88 Wireless Systems Compatibility Reference Book

    • Receiving and Working Technical Contributions

  • Cognizant of Technical Work and Relevant Technical Contributions Related to IAFC Digital Working Group

    • TR-8 Focal Point within TIA/P25 Community

    • Institute of Telecommunication Sciences (ITS) Work


Vocoder Task Group

  • End-Quick Overview

  • Comments & Questions

  • Selected Voice Quality Test Results from Published Documents Follow for Those with Interest

Thank-You


Experiment 1 Results – Fig 9-1 TSB-102.BABE

  • MOS Test 2003 and 2004, TSB-102.BABE

    • Measured audio quality of enhanced vocoders in two experiments.

    • 5 channel conditions:1mph(1%), 5mph(1% & 3%), 60mph (3% & 5%)Soft decision C4FM channel

    • Clean condition

    • 3 noise conditions: Car (10dB SNR), Babble (15dB SNR), Street (10dB SNR), noise spectrum is known

    • Database was 32 sentence pairs from Conformance, TIA-10.BABB.


Experiment 2 Results – Fig 9-2 TSB-102.BABE


Experiment 3 Results – From Fig 9-1 TSB-102.BABF

  • MOS Test 2005, TSB-102.BABF

    • Clean condition

    • 8 noise conditions: 3 fire truck, 2 boat, 2 helicopter, 1 police car

      • SNR and noise spectrum is known

    • Database was 40 sentence pairs recorded by ITS


  • Login