1. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: PHY Proposal for 802.15.4g based on OFDM technology using TV White Space Date Submitted: May 1, 2009 Source: Sangsung Choi, Cheolho Shin and Byounghak Kim, Electronics and Telecommunications Research Institute(ETRI) Voice: +82 42 860 6722, E-maill: sschoi@etri.re.kr Re: [802.15.4g] TG4g Call for Proposals, 2 February, 2009 Abstract: This is a PHY proposal for 802.15.4g based on OFDM technology using TV White Space. Purpose:Technical Proposal to discuss by IEEE 802.15 TG4g 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. Slide 1 May 13, 2009 Sangsung Choi et al., ETRI

2. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space IEEE 802 Interim Session Montreal, Canada May 2009 Slide 2Sangsung Choi et al., ETRI May 13, 2009

3. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space OVERVIEW TV White space PHY Proposal summary for IEEE 802.15.4g SUN Channel for IEEE 802.15.4g PHY Proposal for IEEE 802.15.4g based on OFDM Conclusion Further considerations Slide 3 May 13, 2009 Sangsung Choi et al., ETRI

4. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space TV White space (1) TV White space - slivers of unused spectrum that sit between licensed broadcast channels DTV spectrum (USA, Korea, etc) - Low VHF (CH 2 ~ CH 4) : 54~72MHz - Low VHF (CH 5 ~ CH 6) : 76~88MHz - High VHF (CH 7 ~ CH 13) : 174~216MHz - UHF (CH 14 ~ CH 51) : 470~698MHz The Federal Communications Commission approved unlicensed wireless devices that operate in the empty "white space" between TV channels. - 2008.11.02 Slide 4 May 13, 2009 Sangsung Choi et al., ETRI

5. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space TV White space (2) Fixed device and personal/portable devices can be operated in the TV white spaces on an unlicensed basis. TypesInterference avoidanceTX Power Fixed  Geolocation /database access  Spectrum sensing 4W EIRP Personal/ Portable  Geolocation/database access  Spectrum sensing 100mW EIRP  Without geolocation/database access - Under the control of fixed device or - Under the control of personal/portable device with geolocaion/database access and spectrum sensing capability  Spectrum sensing  Spectrum sensing only50mW EIRP Slide 5 May 13, 2009 Sangsung Choi et al., ETRI

6. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space Advantages of TV White space - Use the similar TV channel frequencies all over the world - There is no special interference source except the TV signals. - Robust against diffraction loss in building area. - Better propagation characteristic than 900 MHz or 2.4GHz - Support maximum TX power of 36dBm for fixed service. A good candidate for SUN application - The most efficient spectrum for low-rate WPAN - Aggressive approach of White space application in 802.11, 16, 22 TV White space (3) Slide 6 May 13, 2009 Sangsung Choi et al., ETRI

7. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space Proposal Summary Frequency: TV white space –UHF (CH 14 ~ CH 51) : 470~698MHz TX power limit: Max. 4W EIRP(36 dBm), Min. 50mW EIRP(17 dBm), Geolocation/database access, Spectrum sensing: -114dBm Modulation –OFDM/QPSK Data rates: 100/200/450/900 kbps Convolutional encoder No Frequency Hopping Slide 7 May 13, 2009 Sangsung Choi et al., ETRI

8. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space Select the free TV channel for IEEE 802.15.4g considering the Regional TV Channel DB - easy obtain White space for SUN SUN Channel for IEEE 802.15.4g(1) 60 Km Slide 8 May 13, 2009 Sangsung Choi et al., ETRI

9. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space SUN Channel for IEEE 802.15.4g(2) Can use 5 SUN Channels per 1 TV Channel Can configure 5 piconets simultaneously. Slide 9 May 13, 2009 Sangsung Choi et al., ETRI

10. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (1) Benefits of Modification of MB-OFDM UWB Spec. –Verified system performance in WiMedia UWB. –Quicker time to market by modification of UWB spec. –Suitable architecture to be a low power, low complexity CMOS solution. Critical Constraints; Power consumption –Actual power consumption will be dependent upon the Fab. process and the architecture.  The proposed architecture can be simplified considering the multipath delay of SUN applications -> can simplify IFFT architecture or channel coding method etc.  CMOS process under 65nm is realizable in current CMOS technology. Slide 10 May 13, 2009 Sangsung Choi et al., ETRI

11. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (2) Proposed SUN Specification Data Rate (Kbps) ModulationCoding Rate (R) FDSTDS Low Data Rate 100QPSK1/3YES 200QPSK1/3NOYES High Data Rate 450QPSK3/4NOYES 900QPSK3/4NO FDS: Frequency-Domain Spreading TDS: Time-Domain Spreading Slide 11 May 13, 2009 Sangsung Choi et al., ETRI

12. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (3) Timing-related parameter ParameterDescriptionValue fsSampling frequency960 KHz NFFTFFT Size128 ∆fSubcarrier frequency spacing7.5 KHz TFFTIFFT and FFT period133.3 us NCPNumber of samples in cyclic prefix32 TCPCyclic prefix duration in time33.3 us NSYMTotal Number of samples per symbol160 TSYMSymbol interval166.7 us Slide 12 May 13, 2009 Sangsung Choi et al., ETRI

13. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (4) 128 IFFT Total of 128 tones: - 100 data tones used to transmit information (constellation: QPSK). - 12 pilot tones used for carrier and phase tracking. - Remaining 16 tones including DC are NULL tones. Slide 13 May 13, 2009 Can design the 16/32/64 point IFFT/FFT considering the Multipath delay of SUN applications Sangsung Choi et al., ETRI

14. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (5) Generation of OFDM Symbol Slide 14 May 13, 2009 Sangsung Choi et al., ETRI

15. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (6) Structure of OFDM Symbol Slide 15 May 13, 2009 Sangsung Choi et al., ETRI

16. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (7) FDS: Frequency-Domain Spreading TDS: Time-Domain Spreading Slide 16 May 13, 2009 Sangsung Choi et al., ETRI

17. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (8) packet structure of SUN system: should be modified for SUN system ▣ PLCP Preamble Deterministic sequence Allows packet detect ▣ PLCP Header Encoded at 100 Kbps Include the PHY information ▣ Payload Encoded at 100 to 900 Kbps Slide 17 May 13, 2009 Sangsung Choi et al., ETRI

18. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (9) Synchronization using packet structure - SUN system needs the shorter preamble compared with UWB system because it doesn’t use frequency hopping. PS (Packet synchronization sequence) FS (Frame synchronization sequence) CE (Channel Estimation Sequence) Slide 18 May 13, 2009 Sangsung Choi et al., ETRI

19. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (10) Channel Model for SUN system is very important to design the OFDM symbol structure. The length of CP should be longer than Multipath delay not to degrade the OFDM performance Channel Model should be modeled to design the optimum specification and to estimate the performance for SUN system Slide 19 May 13, 2009 Sangsung Choi et al., ETRI

20. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (11) TX/RX architecture Slide 20 May 13, 2009 Sangsung Choi et al., ETRI

21. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (12) Out-of-band emission into the 1 st adjacent TV channel The transmitted spectral mask shall have the break point of -55dB at the 1 st adjacent TV channel (Estimation Condition: 100KHz resolution bandwidth) Slide 21 May 13, 2009 Sangsung Choi et al., ETRI

22. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space PHY Proposal for IEEE 802.15.4g based on OFDM (13) Pass Loss Margin for Link budget Minimum sensitive at the receiver - -108dBm @ 100 kbps - -95.2dBm @ 900 kbps TX power - Max. 4W EIRP(36 dBm) - Use Transmit Power Control (36 dBm -> 17dBm) Pass Loss Margin for link budget - 144dB @ 100 kbps - 131dB @ 900 kbps Slide 22 May 13, 2009 Sangsung Choi et al., ETRI

23. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space Conclusion TV White space application is a good candidate for SUN –There is no special interference source except TV signal. –Use the similar TV Channel frequencies all over the world OFDM technology can satisfy SUN requirement easily –Verified system performance in UWB, WLAN, WiMAX,… –Robust against multipath –Easy modification based on channel bandwidth and characteristics  Trade off data rate vs occupied bandwidth CP length vs IFFT size - Two classes of data rate to assist the various applications  Low data rate: 100, 200 Kbps High data rate: 450, 900 Kbps Slide 23 May 13, 2009 Sangsung Choi et al., ETRI

24. IEEE 802.15-09-0275-02-004g PHY Proposal for 802.15.4g based on OFDM technology using TV White Space Further Considerations Modification of proposed SUN architecture - Reduce IFFT/FFT Size to minimize the power consumption  Can design the 16/32/64 point IFFT/FFT considering the Multipath delay of SUN applications - Choose simple FEC according to service radius of application and Channel model.  enough Pass Loss Margin for link budget. 144dB @ 100 kbps, 131dB @ 900 kbps Consideration of alternate spectrum - If no consensus of White space, consider 900MHz ISM band  The unlicensed band 917 MHz ~ 923.5 MHz is assigned for RFID devices and Wireless Sensor Networks in Korea. Slide 24 May 13, 2009 Sangsung Choi et al., ETRI