doc.: ieee 802.22-05/0102r1 submission november 2005 hach, lampe; nanotronslide 1 nanotron mdma ebm...

November 2005

Hach, Lampe; Nanotron

Slide 1

doc.: IEEE 802.22-05/0102r1

Submission

Nanotron MDMA EBM ProposalIEEE P802.22 Wireless RANs Date: 2005-11-07

Name Company Address Phone email John Lampe Nanotron

Technologies GmbH

Alt-Moabit 60, 10555 Berlin, Germany

+49 30 399 954 0

[email protected]

Rainer Hach Nanotron Technologies GmbH

Alt-Moabit 60, 10555 Berlin, Germany

+49 30 399 954 0

[email protected]

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 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 [email protected].>

November 2005


Slide 2

doc.: IEEE 802.22-05/0102r1

Submission

Abstract

• A brief history of chirp pulses

• CSS properties

• MDMA

• EBM

• MCP

• Summary

November 2005


Slide 3

doc.: IEEE 802.22-05/0102r1

Submission

Basic Technologies

MDMAMulti Dimensional Multiple Access New modulation technique High data rates Robust Flexible Easy to implement

MCPMulti Choice Precoding Echo cancellation method Easy to implement on subscriber side Uses the energy of reflected waves Enabler in non-LOS environments

SDS-TWR and TOASymmetric 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 re-

applied

November 2005


Slide 4

doc.: IEEE 802.22-05/0102r1

Submission

Introduction

• MDMA, EBM and MCP were designed for the WRAN-type of problem:– Base station to multiple subscribers

– Dynamic allocation of spectrum

– Dynamic trade-off of range and data rate

November 2005


Slide 5

doc.: IEEE 802.22-05/0102r1

Submission

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-90s

• Chirp Spread Spectrum for commercial wireless data transmission investigated & patented by Nanotron since 1996

November 2005


Slide 6

doc.: IEEE 802.22-05/0102r1

Submission

Characteristics of Chirp Pulses

A chirp pulse is a frequency modulated pulse

Up-Chirp in the time domain(roll-off factor 0.25)

Spectrum of the chirp pulse withbandwidth B and a roll-off factor of 0.25

B

|S(f)|

f

November 2005


Slide 7

doc.: IEEE 802.22-05/0102r1

Submission

The Solution – CSSHas optimal signal forms for both RF link and baseband

November 2005


Slide 8

doc.: IEEE 802.22-05/0102r1

Submission

Key Properties of CSS• High robustness

Due to the high BT product and their asynchronous nature, chirppulses are very resistant against disturbances.

• Multipath resistantDue to the frequency spreading of chirp pulses, CSS is very immune against multipath fading; CSS can even take advantage of RF echoes.

• Long rangeDue to high system gain, as well as noise, interference and fading resistance, CSS has exceptional range for a given transmit power and conditions.

• Location awarenessCSS 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.

November 2005


Slide 9

doc.: IEEE 802.22-05/0102r1

Submission

Mobility Property of CSS

Resistance against Doppler effect:The Doppler effect causes a frequency shift of the chirp pulse, whichintroduces a negligible shift of the baseband signal on the time axis.

Example:Bandwidth B of the chirp 64 MHzData rate 1 MbpsRelative speed between transmitter and receiver2000 km/hFrequency shift due to Doppler effect 4.52 kHzEquivalent shift of the message on the time axis 56.5 ps

Note:2000 km/h is equivalent to 1243 miles/hour

November 2005


Slide 10

doc.: IEEE 802.22-05/0102r1

Submission

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 similaritiesb) symmetry in time domain

November 2005


Slide 11

doc.: IEEE 802.22-05/0102r1

Submission

Chirp Properties (cont.)

• Up-converted up-chirp and down-chirp signals each with a total duration of 1µs

November 2005


Slide 12

doc.: IEEE 802.22-05/0102r1

Submission

Chirp Properties (cont.)

• Figure shows the autocorrelation function (ACF) of a chirp and cross-correlation function (CCF) of an up- and down-chirp

– Note that the CCF has a constant low value (compared to DSSS sequences).

November 2005


Slide 13

doc.: IEEE 802.22-05/0102r1

Submission

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 dB

– Eb/N0 at detector input (BER=10E-4) = 12 dB

– In-band carrier to interferer ratio (C/I @ BER=10-4)= 12 dB – 13 dB = -1 dB

– Implementation Loss = 1 … 2 dB

November 2005


Slide 14

doc.: IEEE 802.22-05/0102r1

Submission

0.01 0.1 1 1040

50

60

70

80

90

100

110

120

130Outdoor-Propagation; a = 2.1

distance between transmitter and receive

atte

nuat

ion

[dB

] for

out

door

d1( )r

101

103

120

124

r

km

Output Power @ antenna

Range @ BER=10-3

7 dBm = 5 mW 740 m

9 dBm = 7.9 mW 940 m

26 dBm = 400 mW 6400 m

30 dBm = 1 W 9800 m

Gant = 1 dB Pout = 9 dBm,d = 940 m

Pout = 7 dBm,d = 740 m

Pout = 26 dBm,d = 6.4 km

Pout = 30 dBm,d = 9.8 km

CSS Outdoor Testing Summary

Using:

•64 MHz bandwidth

•2.4 GHz ISM band

November 2005


Slide 15

doc.: IEEE 802.22-05/0102r1

Submission

nanoNET is FCC & ETSI Certified• Certification of Chirp modulation

method caused no problems despite being a completely new technology

• nanoNET 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 V1.2.1 EN 60950-1:2001

• FCC certification is granted

• Japanese certification is granted

November 2005


Slide 16

doc.: IEEE 802.22-05/0102r1

Submission

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)

November 2005


Slide 17

doc.: IEEE 802.22-05/0102r1

Submission

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

November 2005


Slide 18

doc.: IEEE 802.22-05/0102r1

Submission

Utilize time shift –orthogonality of chirp signals

t

frequency

t

amplitude

time overlap

November 2005


Slide 19

doc.: IEEE 802.22-05/0102r1

Submission

MDMA: Time and Frequency Spreading

N O I S E

B

t0 1 t02t1 t2 t3 t4 t5 t6 t7 t 8 t9 t1 0 t11 t12 t13 Time

Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

N O I S E

B


Po

we

r

E1 E1 E1 E1 E1 E1 E1 E1 E1 E1 E1 E1

N O IS E

t1t01t2t02

t3 t4 t5 t6 t7 t 8 t9 t10 t11 t12 t13 t14 t15 t16 t17 t18 t19 Time

Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E 0 E 0

N O IS E

t1t01t2t02


Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E 0 E 0

N O IS E

t1t01t2t02


Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E 0 E 0

N O IS E

t1t01t2t02

t3 t4 t5 t6 t7 t 8 t9 t10 t11 t12 t13 t14 t15 t16 t17 t18 t19

N O IS E

t1t01t2t02


Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E 0 E 0

N O IS E

t1t01t2t02


Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E 0 E 0

N O IS E

t1t01t2t02


Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E 0 E 0

Time

N O IS E

t1t01t2t02


N O IS E

t1t01t2t02


N O IS E

t1t01t2t02


N O IS E

t1t01t2t02


N O IS E

t1t01t2t02


N O IS E

t1t01t2t02


N O IS E

t1t01t2t02


N O IS E

t1t01t2t02


Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

N O IS E

t1t01t2t02


Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

N O IS E

t1t01t2t02


Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

N O IS E

t1t01t2t02


Po

we

r

E 0E 0

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E1

E 0 E 0

Different chirps in amplitude and in frequency spreading

November 2005


Slide 20

doc.: IEEE 802.22-05/0102r1

Submission

MDMA transmitter

Variable data rate pulse generator

Fix duration chirp filter Automatic power control

November 2005


Slide 21

doc.: IEEE 802.22-05/0102r1

Submission

MDMA: The Potential

MDMA can beadapted to thedemands of a givensituation – evenon the fly!

November 2005


Slide 22

doc.: IEEE 802.22-05/0102r1

Submission

EBM: Variation of the Bit Energy and Rate

r [m]r max2010 30 40

E = P T [ W s ] TB B T. (r)

P = constT

E (r)

=

[ W

s

]

TB E r

BR.

2

G

T (r) = E r

PB BRT

.G .

2

E (r) = const .BR

E [Ws]R S O LU TIO N N O 1 : V AR IA T IO N O F T HE B IT DU R A TIO N

November 2005


Slide 23

doc.: IEEE 802.22-05/0102r1

Submission

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

November 2005


Slide 24

doc.: IEEE 802.22-05/0102r1

Submission

Introduction to MCP

(Multiple Choice Pre-coding)

November 2005


Slide 25

doc.: IEEE 802.22-05/0102r1

Submission

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

November 2005


Slide 26

doc.: IEEE 802.22-05/0102r1

Submission

Task

BaseStation

SubsriberUnit 2

SubsriberUnit 3

SubsriberUnit 1

SubsriberUnit 4

Demands: Low Cost Subscriber Units without Equalizing

channel 1

channel 2

channel 3

channel 4

November 2005


Slide 27

doc.: IEEE 802.22-05/0102r1

Submission

Problem of Intersymbol Interference

transmitterchannel,

h(t) H(j)receiver

channel causes Inter-symbol Interference (ISI)

t

example of pulse response of non-ideal channel

+

=t t

November 2005


Slide 28

doc.: IEEE 802.22-05/0102r1

Submission

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

November 2005


Slide 29

doc.: IEEE 802.22-05/0102r1

Submission

BPSK, QPSK principles

real

imag

+1,+1

real

imag

-1 +1

-1,+1

+1,-1-1,-1

November 2005


Slide 30

doc.: IEEE 802.22-05/0102r1

Submission

QPSK on postringing channel I

0 1 2 3 4 5-1.5

-1

-0.5

0

0.5

1

1.5channel

time refered to symbolduration

ampl

itude

magnitudereal imag

-2 -1 0 1 2-2

-1

0

1

2transmitted constellation

real

imag

-2 0 2-3

-2

-1

0

1

2

3received constellation

real

imag

November 2005


Slide 31

doc.: IEEE 802.22-05/0102r1

Submission

BPSK on post-ringing channel I

0 1 2 3 4 5-1.5

-1

-0.5

0

0.5

1

1.5channel


ampl

itude

magnitudereal imag

-2 -1 0 1 2-2

-1

0

1


real

imag

-2 0 2-3

-2

-1

0

1

2


real

imag

November 2005


Slide 32

doc.: IEEE 802.22-05/0102r1

Submission

QPSK on post-ringing channel II

0 1 2 3 4 5-1.5

-1

-0.5

0

0.5

1

1.5channel


ampl

itude

magnitudereal imag

-2 -1 0 1 2-2

-1

0

1


real

imag

-2 0 2-3

-2

-1

0

1

2


real

imag

November 2005


Slide 33

doc.: IEEE 802.22-05/0102r1

Submission

BPSK on post-ringing channel II

0 1 2 3 4 5-1.5

-1

-0.5

0

0.5

1

1.5channel


ampl

itude

magnitudereal imag

-2 -1 0 1 2-2

-1

0

1


real

imag

-2 0 2-3

-2

-1

0

1

2


real

imag

November 2005


Slide 34

doc.: IEEE 802.22-05/0102r1

Submission

The MCP Principle: definition of multiple representations

real

imag

-1

-1 +1

+1

November 2005


Slide 35

doc.: IEEE 802.22-05/0102r1

Submission

MCP principles:definition of desired detection areas

real

imag

quadrantswhich represent +1

quadrantswhich represent -1

desired detection areafor quadrant III

safety margin

November 2005


Slide 36

doc.: IEEE 802.22-05/0102r1

Submission

MCP principles:possible choice for transmission of -1

Pre-calculate the expected ISI andchoose a representation for the actual information symbol which minimizes the required transmission power

real

imag

desired detectionareas for -1

pre-calculated ISI

November 2005


Slide 37

doc.: IEEE 802.22-05/0102r1

Submission

MCP principles:possible choice for transmission of +1

real

imag

desired detectionareas for +1

pre-calculated ISI

November 2005


Slide 38

doc.: IEEE 802.22-05/0102r1

Submission

0 1 2 3 4 5-1.5

-1

-0.5

0

0.5

1

1.5channel

ampl

itude

-2 -1 0 1 2-2

-1

0

1

2information constellation

real

imag

-2 -1 0 1 2-2

-1

0

1


real

imag

-2 0 2-3

-2

-1

0

1

2


real

imag

MCP on post-ringing channel

November 2005


Slide 39

doc.: IEEE 802.22-05/0102r1

Submission

Comparison, block diagram

2 PAM Source

MCP channelFIR-Filter

transmitter

2 PAM Source

threshold detection

transmitter

FIR-Filter

Decision Feedback Equalizer

channel

threshold detection

receiver

receiver

receivedbits

receivedbits

2 PAM Source

transmitter

Maximum Likelihood Sequence Estimation (Viterbi Algorithm)channel

receiver

receivedbits

November 2005


Slide 40

doc.: IEEE 802.22-05/0102r1

Submission

Comparison FIR-MCP, FIR-DFE, VA

0 1 2 3 4 5 6-1

-0.5

0

0.5

1channel (rot: Realteil, grün: Imaginärteil)

0 5 10 15 20 2510

-5

100

SN

BE

R

FIR-MCPBPSK-VAFIR-DFE

November 2005


Slide 41

doc.: IEEE 802.22-05/0102r1

Submission

Problem of increased crest factor

Solution: instead of “symbol-wise MCP“ use “look ahead MCP“

informationsymbolsource MCP

informationsymbolsource MCP

T T

November 2005


Slide 42

doc.: IEEE 802.22-05/0102r1

Submission

Symbol-wise vs. look-ahead MCPsignal magnitude

0 50 100 150 200 250 300 350 400 450 5000

1

2

3

4ab

s( )

magnitude of transmitted signal, symbol-wise MCP

0 50 100 150 200 250 300 350 400 450 5000

1

2

3

4

time

abs(

)

magnitude of transmitted signal, look-ahead MCP

November 2005


Slide 43

doc.: IEEE 802.22-05/0102r1

Submission

Symbol-wise vs. look-ahead MCP,cumulative energy

0 50 100 150 200 250 300 350 400 450 5000

100

200

300

400

500

600

700

800

900

1000

time

cumulative energy

QPSK symbolwise MCPlook-ahead MCP

November 2005


Slide 44

doc.: IEEE 802.22-05/0102r1

Submission

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 symbol-wise MCP can be avoided by “look-ahead“ strategy.

• MCP can reduce the average transmission power.

November 2005


Slide 45

doc.: IEEE 802.22-05/0102r1

Submission

Technology Conclusions

CSS:• Adds location-awareness • Enhances robustness, range, and mobility• Implementable with today’s technologies• Globally certifiable• Supported by global research

November 2005


Slide 46

doc.: IEEE 802.22-05/0102r1

Submission

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

November 2005


Slide 47

doc.: IEEE 802.22-05/0102r1

Submission

To Be Done…

• Merge with other proposers

• Complete system design

• Channel model simulations

November 2005


Slide 48

doc.: IEEE 802.22-05/0102r1

Submission

Thank you very much!

doc.: ieee 802.22-05/0102r1 submission november 2005 hach, lampe; nanotronslide 1 nanotron mdma ebm...

Documents