November 2005 doc IEEE 802 22 050102 r

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Nanotron MDMA EBM Proposal Authors: IEEE P 802. 22 Wireless RANs Date: 2005 -11 -07 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 Chair Carl 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. > Submission 1 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Abstract • • • A brief history of chirp pulses CSS properties MDMA EBM MCP Summary Submission 2 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Basic Technologies MDMA MCP Multi Dimensional Multiple Access Multi Choice Precoding § New modulation technique § High data rates § Robust § Flexible § Easy to implement § Echo cancellation method § Easy to implement on subscriber side § Uses the energy of reflected waves § Enabler in non-LOS environments SDS-TWR and TOA Symmetric Double Sided Two Way Ranging and Time of Arrival • New ranging method with best accuracy per MHz • Chirp-based pulse edge arrival accuracy using well-known principles reapplied Submission 3 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Introduction • MDMA, EBM and MCP were designed for the WRANtype of problem: – Base station to multiple subscribers – Dynamic allocation of spectrum – Dynamic trade-off of range and data rate Submission 4 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 A Brief History of Chirp Pulses • Used by dolphins and bats • Patent for radar applications about 1940 by Prof. Hüttmann, further developed by Sidney Darlington (Lifetime IEEE Fellow) in 1947 (”Pulse Compression Radar“) • Patented by Canon for data transmission in fiber optic systems in mid-90 s • Chirp Spread Spectrum for commercial wireless data transmission investigated & patented by Nanotron since 1996 Submission 5 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Characteristics of Chirp Pulses A chirp pulse is a frequency modulated pulse |S(f)| f B Spectrum of the chirp pulse with bandwidth B and a roll-off factor of 0. 25 Submission Up-Chirp in the time domain (roll-off factor 0. 25) 6 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 The Solution – CSS Has optimal signal forms for both RF link and baseband Submission 7 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Key Properties of CSS • High robustness Due to the high BT product and their asynchronous nature, chirp pulses are very resistant against disturbances. • Multipath resistant Due to the frequency spreading of chirp pulses, CSS is very immune against multipath fading; CSS can even take advantage of RF echoes. • Long range Due to high system gain, as well as noise, interference and fading resistance, CSS has exceptional range for a given transmit power and conditions. • Location awareness CSS gives the ability to determine the distance (range) between two stations. • Low PHY latency With CSS a wireless connection can be established very quickly because synchronizations on carrier frequency and data clock are not required. • Antenna position Reception is possible with almost any antenna position due to the wide bandwidth. Submission 8 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Mobility Property of CSS Resistance against Doppler effect: The Doppler effect causes a frequency shift of the chirp pulse, which introduces a negligible shift of the baseband signal on the time axis. Example: Bandwidth B of the chirp Data rate Relative speed between transmitter and receiver Frequency shift due to Doppler effect Equivalent shift of the message on the time axis 64 MHz 1 Mbps 2000 km/h 4. 52 k. Hz 56. 5 ps Note: 2000 km/h is equivalent to 1243 miles/hour Submission 9 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Chirp Properties • • Complex values of a windowed baseband up-chirp and down-chirp signals each with a total duration of 1µs Flat magnitude Plenty of roll-off time (easy to implement & meet regulatory requirements) Significant simplification of correlator due: a) to up-chirp and down-chirp similarities b) symmetry in time domain Submission 10 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Chirp Properties (cont. ) • Up-converted up-chirp and down-chirp signals each with a total duration of 1µs Submission 11 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Chirp Properties (cont. ) • Figure shows the autocorrelation function (ACF) of a chirp and crosscorrelation function (CCF) of an up- and down-chirp – Note that the CCF has a constant low value (compared to DSSS sequences). Submission 12 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Support for Interference Ingress • Example (without FEC): – – – Bandwidth B of the chirp = 20 MHz Duration time T of the chirp = 1 µs Center frequency of the chirp (ISM band) = 2. 437 GHz Processing gain, BT product of the chirp = 13 d. B Eb/N 0 at detector input (BER=10 E-4) = 12 d. B In-band carrier to interferer ratio (C/I @ BER=10 -4) = 12 d. B – 13 d. B = -1 d. B – Implementation Loss = 1 … 2 d. B Submission 13 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 CSS Outdoor Testing Summary Pout = 30 d. Bm, d = 9. 8 km Using: Pout = 26 d. Bm, d = 6. 4 km • 64 MHz bandwidth • 2. 4 GHz ISM band Pout = 7 d. Bm, d = 740 m Pout = 9 d. Bm, d = 940 m Gant = 1 d. B Output Power @ antenna 7 d. Bm = Range @ BER=10 -3 5 m. W 740 m 9 d. Bm = 7. 9 m. W 940 m 26 d. Bm = 400 m. W 6400 m 30 d. Bm = 1 Submission W 9800 m 14 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 nano. NET is FCC & ETSI Certified • Certification of Chirp modulation method caused no problems despite being a completely new technology • nano. NET is compliant with the ETSI regulations for the ISM Band: R&TTE Directive 1999/5/EC and the standards EN 300 328 V 1. 4. 1: 2003 EN 301 489 -17 V 1. 2. 1 EN 60950 -1: 2001 • • FCC certification is granted Japanese certification is granted Submission 15 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 WRAN scenario • One basestation May be a little sophisticated • Multiple subscribers Should be inexpensive – Big differences in distance Different link attenuations have to be managed • Some very closed to the basestation • Some far away • Limited Transmit power Max allowed Tx power should be utilized most of the time • Asymetric data rate (Downlink > Uplink) Submission 16 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 How to handle the different link attenuations ? Trade data rate against received symbol energy • Common approach: – Have a fixed symbol rate, adapt the code rate – Drawback: At some point the syncronization will fail and thus the link will break • Alternative approach: – MDMA / EBM • Implicitly vary the symbol energy by adapting the Tx data rate such that the Rx symbole energy stays constant (indepent from distance)accordin to changing the number of overlapping chirp symbols Submission 17 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Utilize time shift –orthogonality of chirp signals frequency t amplitude t time overlap Submission 18 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 MDMA: Time and Frequency Spreading Different chirps in amplitude and in frequency spreading Submission 19 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 MDMA transmitter Variable data rate pulse generator Submission Fix duration chirp filter 20 Automatic power control Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 MDMA: The Potential MDMA can be adapted to the demands of a given situation – even on the fly! Submission 21 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 EBM: Variation of the Bit Energy and Rate Submission 22 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 What can we do with a sophisticated base station? Apply precoding to compensate multipath reflections • Under the assumption that FDD is used, the base station can estimate the channel impulse response for each downlink from the uplink signal • Several precoding schemes that utilize the knowledge of the channel at the transmitter are known. A special one for heavy reflections is MCP Submission 23 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Introduction to MCP (Multiple Choice Pre-coding) Submission 24 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Introduction to MCP (Multiple Choice Pre-coding) • Task • Problem and known possible solutions • Constellations of BPSK, QPSK • MCP principle • Constellations of MCP • Comparison of MCP with DFE and VA • Crest factor and mean symbol energy • Summary of MCP properties Submission 25 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Task Subsriber Unit 1 Subsriber Unit 2 channel 1 channel 2 channel 4 Base Station Subsriber Unit 3 channel 3 Subsriber Unit 4 Demands: Low Cost Subscriber Units without Equalizing Submission 26 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Problem of Intersymbol Interference transmitter channel, h(t) H(j ) receiver channel causes Inter-symbol Interference (ISI) example of pulse response of non-ideal channel t + t Submission = 27 t Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Known possible solutions Receiver related: -Equalizer in receiver (fractional spaced, decision feedback) -Maximum Likelihood Sequence Estimation in receiver (Viterbi Algorithm) Transmitter related: -Tomlinson Harashima Pre-coding for uncoded signals, -Trellis-Pre-coding for coded modulated signals new solution: MCP Submission 28 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 BPSK, QPSK principles imag -1, +1 -1 +1 real -1, -1 Submission +1, +1 29 +1, -1 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 QPSK on postringing channel I Submission 30 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 BPSK on post-ringing channel I Submission 31 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 QPSK on post-ringing channel II Submission 32 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 BPSK on post-ringing channel II Submission 33 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 The MCP Principle: definition of multiple representations imag +1 -1 real -1 Submission +1 34 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 MCP principles: definition of desired detection areas imag quadrants which represent +1 quadrants which represent -1 real safety margin desired detection area for quadrant III Submission 35 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 MCP principles: possible choice for transmission of -1 Pre-calculate the expected ISI and choose a representation for the actual information symbol which minimizes the required transmission power imag desired detection areas for -1 pre-calculated ISI real Submission 36 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 MCP principles: possible choice for transmission of +1 desired detection areas for +1 imag pre-calculated ISI real Submission 37 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 MCP on post-ringing channel Submission 38 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Comparison, block diagram transmitter 2 PAM Source receiver MCP transmitter 2 PAM Source Submission channel receiver channel transmitter 2 PAM Source FIRFilter Decision Feedback Equalizer threshold detection received bits Maximum Likelihood Sequence Estimation (Viterbi Algorithm) received bits FIRFilter receiver channel 39 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Comparison FIR-MCP, FIR-DFE, VA Submission 40 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Problem of increased crest factor Solution: instead of “symbol-wise MCP“ use “look ahead MCP“ information symbol source Submission information symbol source MCP 41 T T MCP Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Symbol-wise vs. look-ahead MCP signal magnitude of transmitted signal, symbol-wise MCP 4 abs( ) 3 2 1 0 0 50 100 150 200 250 300 350 400 450 500 magnitude of transmitted signal, look-ahead MCP 4 abs( ) 3 2 1 0 Submission 0 50 100 150 200 250 time 42 300 350 400 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Symbol-wise vs. look-ahead MCP, cumulative energy Submission 43 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 MCP Summary • MCP uses an expanded alphabet of transmission symbols. This leads to different possible representations of the information sequence that is to be transmitted. • MCP is a nonlinear pre-coding method for uncoded signals. • MCP can reduce the channel induced ISI without additional effort in the receiver: • no equalizer->no soft decision -> no ADC • no DSP/computing power is needed • no detection delay appears • Possible increase of crest factor of the transmitted signal in symbolwise MCP can be avoided by “look-ahead“ strategy. • MCP can reduce the average transmission power. Submission 44 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Technology Conclusions CSS: • • • Adds location-awareness Enhances robustness, range, and mobility Implementable with today’s technologies Globally certifiable Supported by global research Submission 45 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Technology Conclusions MDMA: • The future of CSS • Allows dynamic range / data rate trade-off • Channel sensing enables adaptive use of available spectrum • MCP allows further benefit from knowledge of the channel conditions • EBM facilitates resource efficiency Submission 46 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 To Be Done… • Merge with other proposers • Complete system design • Channel model simulations Submission 47 Hach, Lampe; Nanotron

November 2005 doc. : IEEE 802. 22 -05/0102 r 1 Thank you very much! Submission 48 Hach, Lampe; Nanotron