TDMA Harmonization Agreements TDMA Harmonization Agreements M A COM 19 April

							TDMA Harmonization Agreements

M/A-COM
19-April-2007
 TDMA Harmonization Agreements

 • In TDMA TG Harmonization Agreements, 06-115-R6*, four TDMA Attributes
  were colored yellow—continuing work
  – Modulation -- unresolved
  – NAC Equivalent – resolved, turn yellow to green
  – DUID – resolved, turn yellow to green
  – Ramp & Guard – potentially resolved (?)
 • For TDMA Attribute -- continued work
  – Motorola raised concerns about modulation, simulcast delay spread
    performance through 07-006 – TDMA – Motorola Summary of Phy Status,
    Jan 4, 2007, see next chart
  – Continued contribution/evaluation/discussion in TDMA TG to date
* 06-115-R5, TDMA Harmonization Agreements, TDMA TG Report to the
Project 25 Steering Group, APIC, and User Needs, Jan 8-12, 2007, Mesa, AZ

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12kbps Linear p/4 DQPSK Downlink
(no pilots) Performance Summary
    Non-simulcast performance meets or exceeds the
     Phase 1 family of modulations
    Simulcast coverage meets or exceeds performance of
     C4FM
    Simulcast coverage falls short when compared to the
     modulations used in most simulcast scenarios for
     Phase 1 – a potential issue for existing Phase 1
     simulcast customers
            A reduction in coverage area on the order of
             6-20% was seen, the actual loss depends
             on specific coverage criteria (mobile vs.
             portable, in-building design, terrain etc).
                   8 800MHz systems were reviewed by Motorola:
                         3 had ~6% reduction in coverage area
                         3 had ~12-15% reduction in coverage area
 19-Apr-2007 v0.5
                         2 had ~20% reduction in coverage area      3
Simulcast Delay Spread Summary

•   M/A-COM contends the delay spread issue is resolved by the EHR vocoder
    performance improvement by itself (60+ usec)        (07-034)
•   M/A-COM has presented many other independent techniques to allay
    concerns even more
    •   I/F Bandwidth adjustment                        (07-009)
    •   Enhanced symbol sampling                        (07-009)
    •   H-D8PSK modulation                              (07-050)
    •   Coverage design considerations (timing, etc.)   (07-009, 07-064)
    •   Equalizers                                      (07-009)
•   EADS has presented vocoder FEC techniques that could improve the
    vocoder BER performance even more, increasing the delay spread
    capabilities of 12 kbps way above today’s 9600


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 Simulcast Delay Spread Updates - 1
• Motorola has recently clarified that their 9.6 kbps TDMA proposal uses
  a C4FM baseline with linear modulation as a manufacturer’s option
  (not part of the standard)
 – Proposal defined by TDMA CAI 0.89
 – Does not preclude linear modulation for downlink for enhanced delay
   spread performance
 – But, does not propose standardizing as part of Ph 2
 – So, Motorola 9.6 proposal offers C4FM 50 usec, 5 % BER delay
   spread performance
• Harmonized 12 kbps proposal offers enhanced delay spread capability
 – 80 usec, 5 % BER with H-DQPSK downlink
 – (Even H-CPM downlink (before changed to H-DQPSK in Frisco)
   offers equivalent/better delay spread performance than 9.6 proposal)
                                                             page 5 / 19-Apr-2007 v0.5
 TDMA Attribute – Modulation (including
 Simulcast Delay Spread) Recommendation
• Harmonized 12 kbps proposal offers enhanced delay spread capability
 – As noted, M/A-COM believes stretch goal is met
 – Exceeds delay spread capability of Motorola 9.6 proposal
 – Additional options have been contributed to enhance even further if
   desired
 – Also, manufacturer options could be considered (as Motorola says
   for their 9.6 proposal) to enhance even further
• M/A-COM believes contributions and options provide a sufficient base
  of practical techniques to achieve enhanced delay spread within the
  12 kbps harmonized proposal that the TDMA Attribute – Modulation,
  Simulcast Delay Spread should be considered resolved
 – M/A-COM recommends turning this attribute from yellow to green

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