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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [PHY Considerations for NAN] Date Submitted: [01 July, 2008] Source: [Jeritt Kent] Company [Analog Devices] Address  Voice: E-Mail:[Jeritt.Kent@analog.com] Re: [Neighborhood Area Networking Interest Group] Abstract: Discussion of PHY Considerations and Options for NAN. Purpose: To stimulate discussion in the IG-NAN 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. Jeritt Kent, Analog Devices
PHY Considerations forNeighbourhood Area NetworkingJeritt KentAnalog Devices, Inc.Presentation to the IEEE 802.15 Interest Group for Neighbourhood Area Networks(IG-NAN)
Agenda • Analog Devices Introduction • PHY Options • Fixed Network (NAN) • In-home meter to device network (HAN) • The Interface • PHY Performance Challenges • Utility Perception of NAN/HAN interface requirements • Interface Challenges
Analog Devices, Inc. Founded in 1965 by Ray Stata FY07 Revenue $2.43 Billion Over 10,000 Products Approximately 8300 Employees Worldwide Traded on the NYSE: ADI ADI Included in S&P 500 Index www.analog.com
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Alcatel Andrew Ericsson Fujitsu Hitachi Huawei Japan Radio Corp (JRC) Hitachi Kokusai Kyocera Lucent Mitsubishi Motorola NEC Nokia Nortel Panasonic Powerwave Putian Samsung Sanyo Siemens UTStarcom Xinwei ZTE Every Cellular Phone Call Made Anywhere in the World Passes Through an ADI Chip 9
Extensive Experience in Power Metering Continue to improve and derive new products from this highly reliable base of products. Support standards that can stimulate even higher volumes. Over 175 Million meters have been deployed with ADI solutions. Expertise ADI has solutions showing that high reliability and low cost are possible. Time 2008 1996
PHY options Frequency Bands (MHz) Phy Option1 Phy Option2 315 460 915 2400 USA (FCC) 2400 187 230 865 433 Europe (ETSI) 950 2400 426 429 Japan (ARIB) 2400 433 490 700 China 424 447 910 2400 S.Korea Meter to in-home device link (HAN). No clear technology leader, however requirement for “mobility” of device, i.e. sell worldwide. 5.8GHz is another possible WW solution. Fixed network, meter to meter link (NAN). Majority of deployments using sub-GHz bands for propagation, network architecture reasons
900 MHz or 2.4 GHz? Advantage 900 MHz 2.4 GHz Reason Transmission range Longer range because of longer wavelength Penetration thru buildings Longer wavelengths travel around obstacles better Usability in other regions 2.4 GHz band can be used worldwide 900/868/433 MHz N.America/EU/China Data Rate Faster data transmission means system can go back to power-down mode sooner Antenna size Smaller antenna (quarter wave whip antenna is only 3.125 cm vs. 8.33 cm) Selectivity 900 MHz band typically less crowded currently, but could this change???
Some trends in RF IC devices… • Sub-GHz (900MHz, for example) sensitivities are better • -110dBm are possible at reasonable data-rates (e.g. 19.2kbps) • More intelligence is being added to digital baseband • Packet handling, security, automatic wake-up, etc. • CMOS is tending to impose a practical limit of +3 to +5dBm maximum output power at 2.4GHz. • This can be easily boosted off-chip. • At sub-GHz +14dBm is possible. • Crystal technology continues to bring price down and performance up…
Crystal Sizes over the past 8 years Insert slide showing XTAL performance and price erosion since 2003 (date for release of 802.15.4 spec) Maybe just a simple line graph 2003 technology (mass loading process for crystal frequency adjusting) could achieve ± 30 ppm as standard and ±10 ppm with lower yield. 2008 technology (reactive ion etching process for crystal frequency adjusting) can achieve ±10 ppm with high yield.
Utility Networks Architecture Reference: 15-08-0199-00-wng0
Sub-GHz PHY Performance Challenges • Sub-GHz band is fragmented worldwide • Meters do not need to be mobile • Japan is opening up 950 – 956MHz band,in addition to meter-to-meter applicationstoday at 426MHz • Europe moving to standardize sub-GHz meter-to-meter link • Lower bandwidth vs. 2.4GHz • May or may not be needed for NAN • Key performance metrics • Link Reliability / Range • RX sensitivity • Co-channel + Adjacent channel rejection • Blocking dynamic range • Spatial diversity • Power consumption • Low standby current • Fast startup time • Low RX-mode current Blocking Resilience Sensitivity Power Consumption Selectivity
2.4GHz PHY Performance Challenges • 2.4GHz ISM band is harsh radio environment • Strong interference/roaming users • High degree of man-made background noise • Strong multipath fading • Higher absorption through concrete vs. lower frequencies • Key performance metrics • Link Reliability / Range • RX sensitivity • Co-channel + Adjacent channel rejection • Blocking dynamic range • Spatial diversity • Power consumption • Low standby current • Fast startup time • Low RX-mode current Blocking Resilience Sensitivity Power Consumption Selectivity
Utility Perception of NAN/HAN interface requirements (Refer to IEEE 802.15-08-0270-00-wng0) • PR01 – The modulation must fit into a 250kHz (-20dB) BW • There are ZIF and LIF architectures available that can meet this requirement • PR02 – The system should be capable of at least 50 separate non-overlapping channels • This is achievable • PR03 – PHY should enable a maximum number of channels within available spectrum: 902-928MHz, 2400-2483.5MHz • Current technology can provide PHY solutions in both of these bands • PR04 – Available channels should be capable of being defined to be non-overlapping • This is achievable • PR05 – PHY modulation/demodulation technologies shall be robust in the presence of simultaneous channel occupancy – co-channel rejection • Current technology can likely meet a -9dB co-channel rejection [Pin = Pin(min) = +10dB] for 802.15.4
Utility Perception of NAN/HAN interface requirements (Refer to IEEE 802.15-08-0270-00-wng0) • PR06 – PHY modulation/demodulation shall be robust with regard to data patterns and pattern lengths being communicated • Current technology provides robust modulation and demodulation with a variety of methods. • PR07 – Only validated packets shall be presented by the PHY to the higher layer calling routines • This is a relatively trivial design task. • PR08 – Minimum receiver sensitivities shall be specified • Current technology can likely meet sensitivities of -90dBm for IEEE802.15.4, -87dBm for 250kbps GFSK @ 2.4GHz, and -77dBm for 2Mbps MSK @ 2.4GHz • PR09 – Minimum receiver adjacent and alternate channel rejection shall be specified • Current technology can likely meet an ACPR (N±1) of less than 52dB and an ACPR (N±2) of less than 60dB for IEEE802.15.4 • PR10 – Minimum frequency stability shall be specified • Many current technologies uses Fractional-N synthesizers. These must have a resolution less than 10kHz and an LO frequency error less than ±30 ppm to meet IEEE802.15.4, and some current technology will provide even better specifications.
Utility Perception of NAN/HAN interface requirements (Refer to IEEE 802.15-08-0270-00-wng0) • PR12 – Maximum transmitter and/or amplifier rise and fall times shall be specified • Existing implementations meet a Tx channel change of 175us max, an Idle to Tx_Idle of 175us max, and a Rx to Tx turnaround of 50us max (on same channel). • PR13 – There shall be an indication of the start time of byte synchronization • Currently implementedin both 2.4GHz and 900MHz solutions. • PR14 – Support shall exist for large unfragmented packets of at least 1.5kB in size • Supportable with inexpensive (<$1) crystals today – onboard SRAM viable
Current 802.15.4 PHY Frame SHR + PHR (1) + Payload (127) CRC CRC-16 part of MAC frame (CRC-16) No check on PHY header DSSS 2.4GHz (O-QPSK) 868/915MHz (BPSK, ASK, O-QPSK) Scrambler No explicit ‘whitening’ Utility objectives Larger PHY frame Handle IP efficiently Stronger CRC More reliable error detection Support longer frame CRC-32 is becoming standard everywhere Channel hopping over lots of channels High Density (radios/m2) Easily implemented (MAC) Better scrambler Coexistence advantages Multiple solutions possible Robust Operation >3dBm output power on the 2.4GHz solution and +13dBm on the 900MHz solution. Challenges for 802.15.4 at the NAN/HAN interface…
Thank you very much for your attention Any Questions?