1. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 1 WAVEFORM MODULATED WRAN SYSTEM IEEE P802.22 Wireless RANs Date: 2006-1-08 Authors: Notice: This document has been prepared to assist IEEE 802.22. 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 grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.22. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures http://standards.ieee.org/guides/bylaws/sb-bylaws.pdf including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chairhttp://standards.ieee.org/guides/bylaws/sb-bylaws.pdf Carl R. StevensonCarl R. Stevenson as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.22 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at patcom@iee.org.patcom@iee.org >

2. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 2 Abstract In this proposal, a system concept is suggested for the IEEE802.22 WRAN standard. A set of waveforms are suggested for WRAN systems. In these systems, one TV channel frequency band is divided into subbands each of which has its own waveform. In the time domain, these waveforms are added and transmitted. Multiple access schemes are suggested by applying orthogonal codes in the frequency domain. Sensing of incumbent signals and dynamic frequency selection (DFS) methods are suggested. These waveforms are generated by utilizing full digital processing in this proposal. These schemes are evaluated by simulation.

3. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 3 CONTENTS Introduction Overview of the system concepts Modulations Multiple access Sensing of incumbent signals Dynamic frequency selection (DFS) Performance evaluation Conclusions

4. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 4 INTRODUCTION

5. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 5 INTRODUCTION/BACKGROUND Use short duration waveforms: purely processed in the time domain, not in frequency domain –Simple concept: only a few components in TX and RX –Simple digital processing  Low complexity  Low cost –No components for processing frequency information except LNA (e.g. filter, osc., etc.) –Excellent co-existence capability due to adaptive frequency band usage – flexible to eliminate forbidden bands (e.g. active incumbent TV user bands, active microphone bands, etc.) Dynamically frequency bands can be assigned to CPEs New waveforms have steep out-of-band rejection around the edges of the band.

6. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 6 BACKGROUND Spectrum usage of TV broadcast industries –the average TV market in the United States uses approximately 7 high- power channels of the 67 that it is allocated. This leaves an abundance of free channels that could be used for wireless access. –With both the House and the Senate having recently passed bills requiring television broadcasts to switch from analog to digital sometime in early 2009, the 700-MHz band (channels 52 to 69) will be cleared of programming and moved to lower frequencies (channels 2 to 51). The 700-MHz band will be set aside for public-safety emergency transponders and for bidding by wireless networks.HouseSenate Three possible ways suggested in one article to protect interference with incumbent users –Listen-Before-Talk (LBT) –Geolocation/Database: GPS receivers installed in CPEs –Local beacon: locally transmitted signal used to identify incumbent users Unused Digital TV Channels Could Increase U.S. Wireless Access, Federal action could allow unused channels at lower frequencies to be used for unlicensed wireless networks, Eric S. Crouch, Medill News Service, PC World, Saturday, November 19, 2005, http://www.washingtonpost.com/wp- dyn/content/article/2005/11/18/AR2005111800083_pf.html

7. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 7 LISTEN-BEFORE-TALK Avoiding the “Hidden Node” problem –An unlicensed device could be in the shadow of a building and be shielded from the TV signals, while a TV antenna at the top of the building might get a good signal.  A detector optimized for a specific class of signals (e.g., TV signals) can be orders of magnitude more sensitive than a normal receiver.  Cooperative sensing of TV spectrum by multiple unlicensed devices could, in effect, improve sensitivity of TV signal detection significantly.

8. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 8 GEOLOCATION/DATABASE Need to keep FCC data up to date –Geolocation systems such as GPS do not generally work indoors and hence could not reliably determine location.  There are advanced GPS technologies used in some cellular telephone systems that actually do work indoors. Furthermore, once the DTV transition is complete,, it will be technologically feasible to conduct indoor geolocation using multiple DTV signals. –The FCC databases on broadcast stations are not 100% accurate and are sometimes slow in catching up to transmitter frequency location changes – a more common problem now during the DTV transition.  If the DTV transition is complete, spectrum use will be more stable and the problems of updating the present FCC systems will become manageable.

9. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 9 LOCAL BEACON Control signal rules can avoid false positives –Short-range radio signals should be used to broadcast channel availability information.  It should be resolved by making rules by FCC specifying that the radio channel used to convey TV channel availability information must be have a range comparable with the geographic validity of the channel availability information.

10. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 10 CHANNEL AVAILABILITY Questioned whether there will be significant channel availability for unlicensed use in major urban areas during the DTV transition. –There is likely to be substantial channel availability during transition. –The issue of channel availability during the DTV transition is likely to be short-lived. –In rural areas, there is spectrum available now and there will be for the foreseeable future. Bill Rose’s email to 22 email reflector, Wed, November 23, 2005 10:05 am –The analysis shows that even in congested markets like Dallas/Ft. Worth, 40 percent of the TV channel spectrum will remain unused after America's DTV transition. In more rural markets like Juneau, Alaska, as much as 74 percent will be available.

11. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 11 INTERFERENCE WITH INCUMBENT USERS 73 million TV sets DTV disruption issue Public safety interference Newsgathering and sports programming production Interference with theaters, churches, and school events Will the proposal “permanently chill investment” in spectrum? Cable services “Eglin AFB incident”

12. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 12 PLAUSIBLE MITHS Myth 1 –‘Digital implementation needs more complexity and is not easily realizable with the state-of-the art technologies.’  Digital implementation can be realized with less complexity and simple hardware and provide full flexibility and adaptivity.  As processing power increases and technologies advance, full digital processing is the trend. Myth 2 –‘Lower frequency is not easy to manage or implement.’  Unless high transmit power is not considered, digital processing method can be easily applied for lower frequency band without using more complex algorithms. Myth 3 –‘Since this technology was not realizable yesterday, today also it is not easy to realize.’  Since technologies advance rapidly, more sophisticated and conceptual ideas should be realized in the near future and considered for future applications.  Moore’s law says that processing power increases double every 18 months: cost and complexity can be decreased with the same rate.

13. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 13 OVERVIW OF THE SYSTEM CONCEPTS

14. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 14 KEY COMPONENTS Modulation Source coding Channel coding/error control –FEC and ARQ Interleaving Waveform generation Antenna Multiple access Dynamic frequency band allocation Synchronization LNA Message relaying: repeaters Sensing of incumbent user signals Dynamic frequency selection (DFS) Transmit power control (TPC) Detection

15. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 15 KEY SYSTEM CONSIDERATIONS Simple design to implement –Adopt full digital implementation: ~8 Msamples/sec DACs/ADCs needed More radiated power efficient –Almost flat spectrum inside the assigned band Use almost full bands assigned to the users –Easy to meet out-of-band requirements (or frequency mask) Need less bits to represent samples for equal out-of-band suppression than other concepts –Achieve maximum range coverage More system flexibility –More flexible to various applications and requirements –More dynamically adaptive to available frequency bands in real-time basis 6, 7, or 8 MHz BW Single band or multiple bands which are adjacent to or depart from each other –Scalable information rate adaptive and dedicated to application Basic physics says (square root of coverage) x (number of simultaneous users) x (information rate/user) = constant –High value of this constant can be achieved Scalable with coverage, number of users, information rate –For. Ex: wide coverage with lower information rate or vice versa Adaptively balancing between uplink and downlink information rates –Basically 1.5 Mbps max for downlink and 384 Kbps for uplink required –Adaptively balancing: symmetric and asymmetric according to specific applications

16. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 16 FREQUENCY PLAN Flexible enough to satisfy any frequency band given and to avoid any forbidden bands  6, 7, or 8 MHz bandwidth can be adopted  A part of a TV channel band can be eliminated due to Part 74 device services  pulse waveforms can be adaptively tailored to any frequency mask or band applied with any forbidden bands With any given frequency band, the whole frequency band can be used to enjoy more transmitted power and achieve higher data rates.  Due to steep suppression around the edges of the band  3.8 dB more power used than Gaussian pulse’s case for the same frequency band  3.8 dB more margin for link budget  One TV channel is divided into 16 subbands – 4 groups and 4 subbands/group

17. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 17 FREQUENCY SUBBANDS One TV channel frequency band is divided into 4 groups Each group has 4 subbands –BW of a subband = 6 MHz /16 = 0.375 MHz –Each subband has its own waveform: base waveform –If a part of a given band should be abandoned – e.g., due to active microphone operation - one or more of corresponding subbands can be eliminated. f subband 1 subband 2subband 3subband 4 f group 1 group 2group 3group 4 X MHzX+6 MHz w 21 w 22 w 23 w 24 base waveform

18. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 18 MODULATIONS

19. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 19 WAVEFORM OF A SUBBAND Base waveform shaping –From mathematical derivation/expression –Shape: duration: 11.2 us Longer waveform durations make more immune to inter-symbol interference (ISI) due to comparably small delay spreads. –Spectrum: almost flat throughout the whole band Flatness depends on the number of samples: more samples/waveform entails flatter spectrum How can waveforms be generated –Digital way?  continuously generated waveforms are sampled by DACs at TX  can be generated with relatively lower sampling rate DACs 90 samples/waveform used for this proposal 2x4=8 base waveforms/group for binary representation: 8x4=32 base waveforms per TV channel 64x4=256 base waveforms/group for 64-ary representation: 256x4=1024 base waveforms per TV channel Max 90x1024=92,160 sample information stored in ROM per TV channel  90 Kbytes ROM per TV channel needed to store waveform information if 8 bits/sample is adopted:  90 K x 100 = 9 Mbytes ROM for 100 TV channels Waveforms are generated using DACs which have a sampling rate of 8 Msamples/sec. –90 samples / 11.2 us = 8 Msamples/sec –Analog way? No idea

20. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 20 WAVEFORMS FOR ONE TV CHANNEL Base waveform –For each subband, there is one base waveform which has flat spectrum almost throughout the subband as shown in the next slide. Group waveforms –Group i has four base waveforms: w i1, w i2, w i3, and w i4 –Group i has a set of waveforms: m ij,=a* w i1 +b* w i2 +c* w i3 +d* w i4 where a, b, c, and d are determined by modulation method applied

21. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 21 BASE WAVEFORM (EX1) The base waveform below –for carrier frequency = 500 MHz, bandwidth = 0.375 MHz, sampling rate = 90 samples/waveform -2-1.5-0.500.511.52 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 time amplitude Figures of a waveform and its spectrum should be replaced

22. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 22 BASE WAVEFORM (EX2) The base waveform below –for carrier frequency =, bandwidth = 3.8 MHz, sampling rate = 20 samples/us -2-1.5-0.500.511.52 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 time amplitude

23. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 23 BASE WAVEFORM (EX2) The base waveform below –for carrier frequency =, bandwidth = 0.469 MHz, sampling rate = 10 samples/us

24. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 24 SPECTRAL FLATNESS vs NO OF SAMPLES/WAVEFORM With the same waveform, spectral flatness and out-of-band suppression depend on the number of samples for the waveform duration –More samples makes the spectrum flatter: flatter inside the band and more suppression outside the band –Power ratio=power with perfectly flat spectrum / power with less perfectly flat spectrum inside the band –For the cases Bandwidth = 0.469 MHz Pulse width = 9 us No. bits/sample = 8 No. samples/waveform = 50, 90, 140, 180, 280, 400

25. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 25 BASE WAVEFORMS OF ONE GROUP For four subbands – assuming each subband has 1 MHz BW –If smaller BW, larger pulse width t (us) 04 + + +

26. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 26 BASE WAVEFORMS OF ONE GROUP For four subbands - for smaller BW, larger pulse width For another example, for a case of BW = 0.469 MHz subband 1 subband 2 subband 3 subband 4 us

27. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 27 SPECTRUM OF MULTIPLE SUBBANDS For no. of samples per waveform: 10

28. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 28 ORTHOGONALITY OF WAVEFORMS For each subband, one base waveform exists –16 base waveforms throughout whole band (or four groups): w 11 (t), w 12 (t), w 13 (t), w 14 (t), w 21 (t),...., w 43 (t), w 44 (t) –Each waveform is almost orthogonal to each other or perfectly orthogonal after de-emphasis at RX Each group has –2**4=16 waveforms for binary base waveform modulation (BPSK) or –4**4=256 waveforms for quaternary base waveform modulation (QPSK) –16**4=256K waveforms for quaternary base waveform modulation (16QAM) –64**4=16M waveforms for quaternary base waveform modulation (64QAM) –These waveforms are orthogonal to each other after de-emphasis at RX m ij,=a* w i1 +b* w i2 +c* w i3 +d* w i4 where a, b, c, and d are complex numbers determined by modulation method applied for BPSK a, b, c, and d are +1 or -1 for QPSK a, b, c, and d are +1, +j, -j or -1 m 1,1 = -w 1 - w 2 – w 3 – w 4,...., m 4,16 = w 13 + w 14 + w 15 + w 16 with BPSK

29. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 29 CORRELATIONS BETWEEN WAVEFORMS Correlation where : kth sample of ith base waveform of a group for N samples/waveform Ratio of correlations = autocorrelation/crosscorrelation for various N values Orthogonality holds for sinusoidal waveforms with some conditions (Orthogonality condition, refer to next slide), but the waveforms used here are not sinusoidal with a fixed envelope –At receiver, de-emphasis can be used to make pure sinusoidal for a period m ij *m ij =(a* w i1 +b* w i2 +c* w i3 +d* w i4 )(a* w i1 +b* w i2 +c* w i3 +d* w i4 ) where m ij is the waveform transmitted and m ij is the waveform generated at RX after de-emphasis After integration for a one waveform duration, only autocorrelation terms remain Orthogonality can hold at receiver during detection for matched waveforms –What is the best sampling frequency such that orthogonality can be achievable? “Power consumption of ADCs goes up exponentially with resolution”, EE times, Jan 17, 2005, pp 49

30. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 30 ORTHOGONALITY OF SINUSIODS A key property of sinusids is that they are orthogonal at different frequencies. That is, This is true whether they are complex or real, and whatever amplitude and phase they may have. All that matters is that the frequencies be different. Note, however, that the sinusoidal durations must be infinity. For length N sampled sinusoidal signal segments exact orthogonality holds only for the hamonics of the sampling rate-divided-by-N, i.e., only for the frequencies These are the only frequencies that have a whole number of periods in samples Ex. N=100 for 4 ns pulse duration, f s =25 GHz f k =k*25*10**9/100=2.5*10**8*k=0.25*k GHz For any integer k, f k can be determined  center frequencies of each subband can be determined http://ccrma.stanford.edu/~jos/r320/Orthogonality_Sinusoids.html

31. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 31 EXAMPLE FOR PREVIOUS SLIDE Frequency band: 500-506 MHz, 6 MHz Bandwidth –Whole band is divided into 16 subbands –Each subband has 0.375 MHz bandwidth –16 Carrier frequencies: 500.1875, 500.5625,..., 505.8125 MHz –Frequency separation = h* f s / N = 0.375 MHz where h is an arbitrary positive integer –f s = N / T = 0.375*N*10**6/h where T is a waveform duration T = h / 0.375 * 10**(-6) = h /0.375 us For ex. for h=1, T=3.2 us, for h=3, T=9.6 us, for h=4, T=13.2 us,... For h=3, T=9.6 us, and

32. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 32 CORRELATIONS BETWEEN TWO BASE WAVEFORMS correlation correlation ratio w 11 w 12 w 13 w 14 w 11 0.020984 1/1 0.0012155 17.264/9.7396 2.2562×10-5 930.05/3957.3 3.4173×10-6 6140.6/9681.8 w 12 0.0012155 17.264/9.7396 0.020984 1/1 6.8651×10-6 305.66/106.69 2.2562×10-5 930.05/3957.3 w 13 2.2562×10-5 930.05/3957.3 6.8651×10-6 305.66/106.69 0.020984 1/1 0.0012155 17.264/9.7396 w 14 3.4173×10-6 6140.6/9681.8 2.2562×10-5 930.05/3957.3 0.0012155 17.264/9.7396 0.020984 1/1 –# of samples = 180 # of samples = 90 –Correlation ratio = autocorrelation/crosscorrelation –Correlations totally depend on the number of samples used.

33. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 33 MODULATION/MULTIPLE ACCESS EFFICIANCY Energy or power efficient?joule/sec –Energy=power*time –Power limited by spectral mask and EIRP P max =PSD/MHz*BW  to use more energy, more time needed to be transmitted  totally related to transmit time  for WRAN, BW~6MHz  short duration waveforms can be used for higher data rates  one possibility to increase energy by using multiple pulses for one bit (or symbol)  need to use more power under frequency mask to have higher power  power constrained with frequency mask and EIRP for WRAN case  new waveforms needed to fit the frequency mask to have more transmitted power Spectrally efficient? bit/Hz –limited bandwidth given –More complex modulation schemes have to be applied  entails higher system complexity Time efficient?bit/sec –For higher rate, more important : needs a short duration waveform for one symbol  Needs to put more information in a symbol duration  Needs more sophisticated modulations

34. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 34 POSSIBLE MODULATIONS FOR EACH WAVEFORM Each waveform can be modulated by using the following modulation schemes depending on required data rates, system complexity, detection method, etc ModulationNo. of levelsComplexityData rateDetection method OOK2 (+1, 0)lowestlowNon-coherent/coherent Anti-podal:BPSK2 (+1, -1)low Coherent/differential QPSK4moderate Coherent/differential n level modnhigh Coherent/differential nQAMnhigh Coherent/differential

35. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 35 SPECTRUM OF BASE WAVEFORM

36. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 36 EXAMPLES OF WAVEFORMS (BPSK) Submission m 1,1 (t)m 1,11 (t) m 1,16 (t)

37. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 37 SIGNAL FOR RANDOMLY GENERATED 10,000 BITS

38. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 38 SPECTRUM FOR SIMULATED SIGNAL For a signal of the previous slide

39. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 39 TRANSMITTER STRUCTURE Simple structure with full digital processing concept –FEC encoder –Interleaver –Waveform generator –Modulator –Antenna Data manipulator modulator waveform generator Data in antenna Source coding Channel coding interleaving This part can be realized using digital processing

40. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 40 TRANSMITTER BLOCK DIAGRAM ROM, group 1 ROM, group 2 ROM, group 3 ROM, group 4 DAC waveform transformer data manipulator S/P converter encoding interleaving encryption input data

41. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 41 RECEIVER STRUCTURE Simple receiver structure –Antenna- Waveform generator –LNA- Demodulator –Data detector –De-interleaver –Channel decoder –Synchronizer demodulator Data De-manipulator waveform generator Synch Information retriever antenna LNA Data out detector

42. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 42 RECEIVING BLOCK delay block ADC correlator ROM LNA Sampling rate ~8 MHz Waveform information stored

43. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 43 MULTIPLE ACCESS

44. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 44 DOWNLINK/UPLINK DUPLEXING Code division duplex (CDD) –Full duplex mode –Provide full flexibility in uplink/downlink balancing Symmetric/asymmetric –More time efficient than TDD and more spectrally efficient than FDD

45. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 45 MULTIPLE ACCESS (MA) Possible MAs considered –Frequency hopping (FH) among subbands/groups Not efficient because of higher system complexity and less usage of power –TDMA Less time efficient More difficult to synchronize –Direct-sequence (DS) CDMA Less time efficient and more complex to process –FDMA/OFDMA More complex New MA needed? f t Group 1 Group 2 Group 3 Group 4 16 frequency bins time domain bins t4t2t3t1t5

46. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 46 MAPPING FREQUENCY BINS TO WALSH ENCODED SYMBOLS

47. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 47 PROPOSED MULTIPLE ACCESS An orthogonal set of 8 8-bit Walsh codes is used –Max autocorrelation, zero crosscorrelation each other –One code consists of 8 frequency domain bins –Minimal Hamming distance of this code set is 4 – mostly 8 One frequency bin error can be corrected while three bin errors can be detected; works like an ECC code; increases robustness 64 simultaneously operated users –For one user, two Walsh codes (16 bits) are assigned –One time domain bin is occupied by two codes two codes represent one symbol; one time domain bin represents one symbol; one time domain bin deliver one symbol Hamming distances between two user codes are 4 and mostly 8. For each frequency bin waveform, BPSK, QPSK, 16QAM or 64QAM is applied according to signal environments – or according to the distance between a CPE and the base station. Use of full frequency band –Codes are spread over the full band – entails higher power efficiency

48. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 48 DUPLEXING/MULTIPLE ACCESS Duplexing –Code division duplexing (CDD) Downlink MA –Orthogonal code assigned with sectorization Walsh codes MA Antenna sectorization: 3 sectors with 120 degrees coverage for each sector  downlink channel capacity increased by three times Uplink MA –Orthogonal code assigned with omni directional antennas  uplink channel capacity increased by three times due to sectorization

49. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 49 SENSING OF INCUMBENT SIGNALS

50. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 50 SPECTRA OF TV CHANNELS Analyzing the Signal Quality of NTSC and ATSC Television RF Signals.htm, Glen Kropuenske, Sencore NTSC and DTV signal spectra

51. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 51 NTSC TELEVISION BAND Conventional Analog Television - An Introduction

52. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 52 NTSC HORIZONTAL BLANKING SIGNAL AND SYNCHRONIZATION PULSE Conventional Analog Television - An Introduction

53. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 53 NTSC COLOR SYNCHRONIZATION SIGNAL – COLOR BURST Conventional Analog Television - An Introduction.htm

54. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 54 NTSC VERTICAL BLANKING SIGNAL Conventional Analog Television - An Introduction

55. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 55 NTSC PHASE REFERENCE OF COLOR BURST Conventional Analog Television - An Introduction

56. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 56 DTV PILOT FREQUENCY Conventional Analog Television - An Introduction Presented at the IEEE Broadcast Technical Society 49th Symposium September 24, 1999 Henry Fries and Brett Jenkins Thales Broadcast & Multimedia, Inc. Southwick, MA

57. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 57 DTV SIGNAL VIEWED ON A SPECTRUM ANALYZER Conventional Analog Television - An Introduction Presented at the IEEE Broadcast Technical Society 49th Symposium September 24, 1999 Henry Fries and Brett Jenkins Thales Broadcast & Multimedia, Inc. Southwick, MA

58. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 58 DTV OUT-OF-BAND “SHOULDERS” Conventional Analog Television - An Introduction Presented at the IEEE Broadcast Technical Society 49th Symposium September 24, 1999 Henry Fries and Brett Jenkins Thales Broadcast & Multimedia, Inc. Southwick, MA

59. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 59 VSB TV PARAMETERS

60. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 60 VSB TV PARAMETERS

61. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 61 TV CHANNELS IN U.S. Currently with 6 MHz bandwidth for each channel, –VHF low band: Chs 2-654-88 MHz –VHF high band: Chs 7-13174-216 MHz –UHF band: Chs 14-69470-806 MHz * After DTV transition, –VHF low band: Chs 2-654-88 MHz –VHF high band: Chs 7-13174-216 MHz –UHF band: Chs 14-51470-698 MHz * In this proposal, channels after DTV transition are considered. Other bandwidths – 7 and 8 MHz – can also be considered by changing system parameters. * Ch 37 is reserved for radio astronomy

62. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 62 SENSING INCUMBENT SIGNALS METHOD 1 (1) TV signal sensing –Use only spectral components Less sensitive on other parameters used to design TV tuners – for example, Phase noise, etc. –Use FFT transform of NTSC and DTV signals at the receiver After wide band tuning and down converting BW=6 MHz Sampling interval T=1/B=1/6 us, sampling rate=BW=6 MHz Frequency resolution F 0 =3 KHz Time period T 0 =1/F 0 =1/3 ms Number of samples needed N 0 =T 0 /T= 2 KHz Needs 2K point FFT

63. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 63 SENSING INCUMBENT SIGNALS METHOD 1 (2) Sensing procedure for TV signals –Several frequency components taken F 1, F 2, F 3,..., F 7 –Compare these values If F 2 /F 4 > th n, this signal is NTSC If F 1 /F 4 > th d, this signal is DTV –Repeat this procedure several times to make sure the sensing results

64. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 64 SENSING INCUMBENT SIGNALS METHOD 1 (3) Sensing wireless microphone signals –Wireless microphone systems according to frequency usage Single frequency systems Frequency agile systems –Wireless systems should NOT be operated on the same frequency as a local TV station. Only open (unoccupied) frequencies should be used. In the U.S., each major city has different local TV stations. –Two possible ways One possible way is to divide vacant TV channels into two groups –One group for WRAN and the other for wireless microphone –Not a practical way because of current incumbent users Another way is to sense the spectral components using FFT devices –Every 100 KHz the spectral component is measured and compared with other components.

65. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 65 SENSING INCUMBENT SIGNALS METHOD 2 After DTV transition in the U.S., –VHF low band: Chs 2-654-88 MHz –VHF high band: Chs 7-13174-216 MHz –UHF band: Chs 14-51470-698 MHz * k consecutive bands in UHF band selected for WRAN applications –The whole band of k bands is divided into kx60 subbands Each band has 60 subbands: each subband has 100 KHz bandwidth –At receiver, the received signal is inputted to 60k point FFT By comparing FFT output signals, currently operated incumbent users can be identified and categorized – NTSC, DTV, or Part 74 devices * Ch 37 is reserved for radio astronomy

66. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 66 DYNAMIC FREQENCY SELECTION (DFS)

67. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 67 DYNAMIC FREQUENCY SELECTION (DFS) Select one or more bands among k bands –Each selected band is divided into 60 subbands. –Each subband in selected bands carries information. –One complex number of information is assigned to each subband For selected bands, one complex number is assigned to each subband –A complex number is determined by the constellation which depends on modulation method adopted for the system: BPSK: two points: can deliver only one bit QPSK: four points: can deliver only two bits 2 n QAM: 2 n points: can deliver only n bits For non-selected bands, zero is assigned to each subband: –by assigning zero to each subband and applying OOK, no signal is transmitted –Dynamic frequency selection can be achieved: by changing the assigned values for subbands dynamically, WRAN band(s) can be selected.

68. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 68 PERFORMANCE EVALUATION

69. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 69 DATA RATES Assumptions –64 simultaneously operated CPEs and a base station per each sector –One TV channel available (6MHz BW) Sectorization factor: 3 –The information rate increases by three times. –Frequency reuse factor: 3 Aggregated data rates estimated per TV channel –BPSK applied for a waveform 1 bit/waveform x 1.43 waveforms/us x 3 sectors= 4.29 Mbps –QPSK applied for a waveform 2 bit/waveform x 1.43 waveforms/us x 3 sectors = 8.58 Mbps –16 QAM applied for a waveform 4 bit/waveform x 1.43 waveforms/us x 3 sectors = 17.16 Mbps –64 QAM applied for a waveform 6 bit/waveform x 1.43 waveforms/us x 3 sectors = 25.74 Mbps Data rates per subscriber –Min 4.29 Mbps/16 = 0.27 Mbps, Max 25.74 Mbps/16 = 1.61 Mbps, both ways Spectral efficiency –Min 4.29 Mbps/6 MHz= 0.72 bits/sec/Hz, Max 25.74 Mbps/6 MHz = 4.29 bits/sec/Hz

70. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 70 EVALUATION PARAMETERS Given –Max EIRP –Frequency band –Spectral mask –Channel models –Coverage or range –S/N for information retrieval for each modulation –Allowable BER or PER for each application –Antenna gain Parameters –S/N vs range –BER or PER vs S/N for each modulation –Interference to other WRAN applications inside band –Interference to applications other than WRAN inside band –Interference to out-of-band applications –Latencies for various applications Results obtained –With these system concepts how high data rates (or throughputs) can be achieved for various ranges?

71. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 71 CONCLUSIONS

72. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 72 SUMMARIZED FEATURES With 6 MHz bandwidth –One band is divided into 16 subbands –Each subband has its waveform: all 16 waveforms are nearly orthogonal to each other –Modulations: BPSK, QPSK, 16QAM, and 64QAM –Sectorization with directional antennas for BSs and omni directional antennas for CPEs Exactly same hardware for CPEs as that without sectorization Three receiving blocks needed for a base station –Multiple access: coded MA in frequency domain 64 users at one instant –Aggregated data rates: min 4.29 Mbps, max 25.74 Mbps –Data rates per subscriber: min 0.27 Mbps, max 1.61 Mbps –Spectral efficiency : min 0.72 bits/sec/Hz, Max 4.29 bits/sec/Hz Advantages over other concepts –Simpler concept: much simpler implementation/lower complexity than other competing technologies –Pure digital implementation –More flexibility in scalability, up/down balancing –Realized with lower sampling rate DACs and ADCs

73. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 73 WHY THIS PROPOSAL? Very simple concepts / architecture –Directly generated pulse waveforms using ROMs –Processing in digital methods No need to have analog devices (e.g., mixer, LO, integrator, etc) except LNAs  low complexity / low cost / low power consumption High out-of-band rejection with equal complexity –More transmit power and more bandwidth efficient  high data rates can be achieved High adaptability to frequency, data rate, transmit power requirements  high scalability in frequency band, data rate, system configuration, uplink/downlink balancing, waveform, etc. More transmit power used under frequency mask –More margin in link budget: 3.8 dB more by using full power under any frequency-power constraints with waveforms adaptive to frequency mask  Spectrally efficient / more received signal power  More chance to intercept signals

74. doc.: IEEE 802.22-05/0107r2 Submission January 2006 Soo-Young Chang & Jianwei Zhang, Huawei TechnologiesSlide 74 References 1.“Power consumption of ADCs goes up exponentially with resolution”, EE times, Jan 17, 2005, pp 49 2.http://ccrma.stanford.edu/~jos/r320/Orthogonality_Sinuso ids.html