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					July 2004                                                          doc.: IEEE 802.15 / 15-04-0327-00-004b
 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

 Submission Title: [OEM Comments]
 Date Submitted: [July 2004]
 Source: [Bernd Grohmann] Company: [Danfoss A/S]
 Address: [E14, DK-6430 Nordborg, Denmark]
 Voice:[+45.7488.3802], FAX: [+ +45.7488.4000], E-Mail:[bernd . grohmann @ danfoss . com]
 Re: [ IEEE 802.15 TG4b ]

 Abstract: [This contribution provides comments and summarizes key requirements to the discussion of
 a 2.4 Ghz derivative PHY for the sub-1-GHz band]

 Purpose:     [To encourage discussion.]

 Notice:       This document has been prepared to assist the IEEE P802.15. It is offered as a basis for
 discussion and is not binding on the contributing individual(s) or organization(s). The material in this
 document is subject to change in form and content after further study. The contributor(s) reserve(s) the
 right to add, amend or withdraw material contained herein.

 Release:   The contributor acknowledges and accepts that this contribution becomes the property of
 IEEE and may be made publicly available by P802.15.




Submission                                          Slide 1                          Bernd Grohmann, Danfoss A/S
July 2004                                          doc.: IEEE 802.15 / 15-04-0327-00-004b

         Rationale for OEM & customer interest
         for improved sub-1-GHz band support
• Actual and perceived high risk of interference in 2.4 GHz band
      – 2.4 GHz band is crowded already, interference problems already –
        2.4 GHz Band will get more crowded (BT, WLAN, WiMedia, Audio etc.)
      – Mobile 2.4 GHz devices “carried around” by people  Uncontrollable !
      – How to guarantee reliable operation for 5+ years ?
        Demanded strongly by our customers already – Risk to market adoption!
• Higher range – Factor 2-3 indoor improvement is desired and required
      – Lower attenuation at 868/915 MHz than at 2.4 GHz,
        passes much better through many relevant materials
      – Current indoor range is largely limited by MP fading robustness
• Eliminate holes in coverage
      – Current 2.4 GHz solution is only barely better than “well-developed”
        868/915 MHz narrowband systems in many indoor environments
• Our assessment is that for 30-50% of the entire target market volume,
  the current 2.4 GHz solution in IEEE802.15.4-2003 is not suitable and
  an improved 868 / 915 MHz solution would be strongly preferred
Submission                              Slide 2                   Bernd Grohmann, Danfoss A/S
July 2004                                                                  doc.: IEEE 802.15 / 15-04-0327-00-004b


Coverage problems due to Multipath Fading
             Good Coverage                                                                      No Coverage
                                                        Insufficient Coverage
        i.e. at more than 90% of
                                                          i.e. no coverage at               i.e. coverage only at
                test points
                                                       > 30...40% of test points            << 10% of test points




 • Test site:                      Danfoss office (brick building, sheetrock walls)                   Test transmitter
 • Tested RF technology:           IEEE802.15.4-2003 (2.4 GHz), 0dBm Tx
 • Shorter range and even higher coverage problems in industrial environments measured !
Submission                                                Slide 3                         Bernd Grohmann, Danfoss A/S
July 2004                                                           doc.: IEEE 802.15 / 15-04-0327-00-004b


    Key requirements for sub-1-GHz band
•    Support of current RF regulatory regimes – Design for future RF extensions
     i.e. support operation in channels with a bandwidth of only 300-600 kHz
      – 2 MHz wide channels are available – but almost only in the USA
             • Permit use of 1...2 MHz channels – but use opportunity for improved robustness, higher bitrate
      – Extension of European (CEPT) 868 MHz band will take several years
             • Currently only strategic plan – Not adopted in April 2004
             • Would first need to be adopted on European level – several years
             • Then need to be implemented in all key countries – more years
      – Support of more flexible channel assignment scheme to flexibly support more countries
•    Bitrate over 200 kBit/s
      – Number of permitted transactions/hr is insuffcient in 868 Mhz band in Europe (CEPT)
             • 1% duty cycle at 20 kbit/s translates into typically only 600-800 transactions/hr
             • With > 200 kbit/s sufficient number of transactions/hr for all targeted applications
             • Disadvantage of 1% duty cycle limit turns into protection against interference
      – Extension from 20/40 kbit/s extends total battery lifetime by 15-40%
•    Improved multipath fading robustness
      – Eliminate issues with insufficient coverage within RF range
      – Mitigate obeserved rapidly and ferquently changing RF link quality
•    Backward compatibility to IEEE802.15.4-2003 (915/868 MHz)
•    Low cost (!)
Submission                                           Slide 4                          Bernd Grohmann, Danfoss A/S

				
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