November 2005 doc IEEE 802 22 050102 r
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Abstract • • • A brief history of chirp pulses CSS properties MDMA MCP EBM Summary Submission 2 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Introduction • MDMA was designed for the WRAN-type of problem: – Base station to multiple subscribers – Dynamic allocation of spectrum – Dynamic trade-off of range and data rate Submission 3 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 4 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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) 5 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 The Solution – CSS Has optimal signal forms for both RF link and baseband Submission 6 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 7 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Channelization and Tuning Flexibility • With digital chirp generation techniques, it is possible to omit frequency ranges in the chirp modulation • This enables fuller spectrum utilization, while avoiding any occupied channels Submission 8 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 10 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Chirp Properties • • Complex values of a windowed baseband up-chirp and down-chirp signals each with Flat magnitude Plenty of roll-off time (easy to implement & meet regulatory requirements) Significant simplification of the correlator due to: – Up-chirp and down-chirp similarities – Symmetry in the time domain Submission 11 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Chirp Properties (cont. ) • Up-converted up-chirp and down-chirp signals each with a total duration of 1µs Submission 12 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 13 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 14 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 15 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 16 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Some MDMA Possibilities • Higher data rates – Due to the linearity of the compression filter the transmitted chirp signals can be overlaid inside the transmitter and separated again in the receiver. • 1 bit/s/Hz – The minimum distance of the received signals is given by the Nyquist theorem as 1/B, so it is possible to design a relatively simple chirp based system with an efficient channel capacity. • PSK and QAM – It is possible to add higher modulations to increase the channel capacity. • Combining all of these possibilities could lead to a robust, highly efficient transmission system Submission 17 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 The Systems single up- & down-chirps parallel chirps sequential chirps Submission 18 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 MDMA: Time and Frequency Spreading Different chirps in amplitude and in frequency spreading Submission 19 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 MDMA: The Potential MDMA can be adapted to the demands of a given situation – even on the fly! Submission 20 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 21 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 22 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Problem of Inter-symbol 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 = 23 t Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 24 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 BPSK, QPSK principles imag -1, +1 -1 +1 real -1, -1 Submission +1, +1 25 +1, -1 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 QPSK on post-ringing channel I Submission 26 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 BPSK on post-ringing channel I Submission 27 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 QPSK on post-ringing channel II Submission 28 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 BPSK on post-ringing channel II Submission 29 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 The MCP Principle: definition of multiple representations imag +1 -1 real -1 Submission +1 30 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 31 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 32 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 MCP principles: possible choice for transmission of +1 desired detection areas for +1 imag pre-calculated ISI real Submission 33 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 MCP on post-ringing channel Submission 34 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 35 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Comparison FIR-MCP, FIR-DFE, VA Submission 36 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Problem of increased crest factor Solution: instead of “symbol-wise MCP“ use “look ahead MCP“ information symbol source Submission information symbol source MCP 37 T T MCP Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 38 300 350 400 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Symbol-wise vs. look-ahead MCP, cumulative energy Submission 39 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 40 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 MCP improves MDMA by using the delay spread energy Submission 41 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 EBM For a given distribution of the subscribers around a base station, we can increase the following: • Distance of the farthest-away subscriber (increasing the diameter of the cell) • Increase data throughput for the entire network (without changing the diameter of the cell) • Increase number of the subscribers, without sacrificing the data rate delivered to individual subscribers Submission 42 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Variation of the Bit Energy and Rate Submission 43 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Adaptive Bit Energy Submission 44 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Technology Conclusions CSS: • • • Combines DSSS and UWB properties Adds location-awareness Enhances robustness, range, and mobility Implementable with today’s technologies Globally certifiable Supported by global research Submission 45 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 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 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 To Be Done… • Merge with other proposers • Complete system design • Channel model simulations Submission 47 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 Thank you very much! Submission 48 Lampe, Nanotron
November 2005 doc. : IEEE 802. 22 -05/0102 r 0 References Submission 49 Lampe, Nanotron
- Slides: 49