doc.: ieee 802.22-10/0054r0 submission march 2010 gerald chouinard, crcslide 1 ofdma-based...

March 2010

Gerald Chouinard, CRCSlide 1

doc.: IEEE 802.22-10/0054r0

Submission

OFDMA-based Terrestrial Geolocation

Name Company Address Phone email Gerald Chouinard

Communications Research Centre, Canada

3701 Carling Ave. Ottawa, Ontario Canada K2H 8S2

(613) 998-2500

[email protected]

Ivan Reede Amerisys Inc. Montreal, Canada (514) 620-8652 [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 802.11.

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 <[email protected]> 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 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <[email protected]>.

AbstractThis contribution summarizes the results of a study done at CRC on the validity and feasibility of including a terrestrial triangulation method for geolocation of WRAN devices based on a precise propagation delay measurement scheme integrated to the 802.22 standard. This is in response to comment #1160 and #1161 to the 802.22 Draft 2.0.

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Review of geolocation technologies and algorithms

Technologies/ Algorithms Advantage(s) Disadvantages Industry Status

Radio Beacons Simplicity, Low cost Clear vision requirement, Very coarse

OLD technology, Aviation use

GPS Prevalent technology Inaccuracy with environment factors, susceptible to multi-path, slow operation

In use

AMPS - Hard to implement Obsolete CDMA Interference robustness Power control issue In use

GSM Timing accuracy System design change requirement In use

Schmidl-Cox Accurate symbol timing Flat region ambiguity, Tx interruption for geolocation In progress

Minn Accurate symbol timing Flat region ambiguity, Tx interruption for geolocation In progress

Morelli-Mengali Accurate symbol timing, use of one training symbol

Flat region ambiguity, Tx interruption for geolocation Hardware complexity

In progress

Amerisys No. Tx interruption for geolocation Phase ambiguity (+2kπ) In progress

Amerisys|CRC No. Tx interruption for geolocation

Phase ambiguity resolved by FFT/IFFT and correlation with complex prototype function

In progress

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Propagation time between Base Station and CPE(Coarse Time Difference of Arrival: TDOA)

BS CPEA1

Downstream

Upstream

1. CPE synchronizes with BS and is in phase-lock with the RF carrier.The sampling frequency (≈ 8/7*BW) is derived from the same clock (§8.12.1)

2. BS and CPE carry out normal association and ranging (RNG-REQ and RNG-RSP, §6.9.5 and §6.9.6) and adjust the advance A1 so that all CPE upstream bursts arrive at the BS at the same time independently of their distance, within ±25% of the smaller cyclic prefix (±2.33 usec or ±16 sampling periods)(A1 is regularly updated by the RNG-RSP message in sampling clock units(TU≈1/(8/7*BW) (e.g., 145.8576 ns for 6 MHz)

(Note: change proposed to the RNG-RSP message to use absolute advance adjustment for A1 rather than relative to have the raw time adjustment available at the BS. Zero advance corresponds to CPE co-located with BS.) (Ф TU advance corresponds to a BS-CPE distance of ≈ Ф*145.8*0.3/2 m)

< RNG-REQ

RNG-RSP >

A1

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Propagation time between Base Station and CPE(Fine Time Difference of Arrival: TDOA)

BS T1 CPEDownstream

Upstream

1. BS transmits a RNG-RSP to the specific CPE and initiates its counter T1 (in TU’s) at the moment where the downstream burst leaves the BS (at the start of the frame preamble).

2. The BS knows exactly the symbols on which the solicited CDMA RNG-REQ will be transmited by the CPE on the upstream since it is registered in the US-MAP. The BS keeps this value T2 in memory (frame symbol number allocated to the start of the RNG-REQ upstream burst).

3. The BS knows the size of the TTG in TU’s (e.g., 1439 TU for 6 MHz),

4. The precise CPE time advance measured when the CPE is co-located with the BS is determined (TCPE in ns) and sent to the BS at registration (to be added to CBC-REQ, §6.10.15.1). A1 is the advance that the BS to adjusts through coarse ranging. (TCPE-A1) is the residual delay.

T2

< RNG-REQ

RNG-RSP >

TTG TCPE

A1

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

802.22 Frame structure

DS sub-frame

TT

G

RT

G

US sub-frame(smal l est US burst por t ion on a given subchannel= 7 symbol s)

26 to 42 symbols cor responding t o bandw idths f rom 6 MHz t o 8 MHz and cycl ic prefi xes f rom 1/ 4 t o 1/ 32

Fram

e Pr

eam

ble

FCH

DS-

MA

P

Burs

t 1DC

D

Burs

t 2 ti

me

buff

er

tim

e bu

ffer

Self

-coe

xist

ence

win

dow

(4 o

r 5

sym

bols

wh

en s

ched

ule

d)

Burst 1

60 s

ubch

anne

ls

Burst 2

Burst 3more than 7 OFDMA symbols

Burst

Burst n

Burst

Burs

t m

Ranging/ BW request / UCS not ifi cat ion

Burst

Burst

Burst s

Burs

ts

fram e n-1 fram e n fram e n+1... Tim e...

10 m s

US-

MA

P

US-

MA

PU

CD

Reference start time for T1 counter

T2

DS-MAP for the RNG-RSP MAC message

RNG-RSP MAC

message

US-MAP for the CDMA

Ranging burst

Solicited CDMA

Ranging burst

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


BS

Vernier-1

T1 CPEDownstream

Upstream

4. Vernier-1 works on the residual phase of the preamble and/or pilot carriers in the downstream to precisely calculate the arrival of the first multipath relative to the synchronization time at the CPE recovered by the preamble correlator (in TU accuracy). (Note that an advance of a few TU’s will be provided in the CPE synchronization scheme to avoid ISI due to pre-echoes.)

5. Vernier-1 uses the information on the frequency domain equalization process done at the CPE. The I&Q values recovered for each active subcarrier from the preamble (and optionally pilot carriers) which will be applied at the output of the FFT to correct the constellations in amplitude and phase for data decoding will collectively represent the channel impulse response referenced to the CPE receiver synchronization time.

T2

< RNG-REQ

RNG-RSP >

TTG TCPE

A1

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Vernier time reference

Useful symbol periodCyclicprefix

Theoretical time reference for the FFT window where the residual phases of the vernier will be zero

Synchronized 2k FFT sampling window

Reference 2k FFT sampling window

Time reference for the FFT window at the CPE resulting from the synchronization scheme using the preamble plus the advance of a number of TU’s to avoid pre-echo leakage)

Typical vernier value (ns) (If first echo is the main signal, will be smaller if a pre-echo exists since line-of-sight distance should rely on the first echo received.)

Channel impulse response

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


BS

Vernier-1

Vernier-2

T1 CPEDownstream

Upstream

7. The CPE responds to the RNG-RSP from the BS with a “re-range or continue” status by sending a CDMA ranging burst during the frame specified in the RNG-RSP message (The upstream map of the specified frame will contain a UIUC=6 for the CDMA ranging burst for the specified symbol offset T2.)

8. BS receives the ranging burst and stops the T1 counter at the arrival of the CDMA ranging burst, precisely at the time of the first sampling period belonging to the burst. (T1 counter is in sampling periods at the BS, in TU’s)

9. BS acquires the I&Q values of the CDMA ranging burst carriers at the output of the FFT and removes the CDMA signature. Off-line signal processing can be applied onto the received 56 reference carriers to resolve the precise time of arrival (ns) of the first multipath relative to the reference sampling time at the BS (Vernier-2).

T2

< RNG-REQ

RNG-RSP >

TTG TCPE

A1

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


BS

Vernier-1

Vernier-2

T1 CPEDownstream

Upstream

10. The values of the frequency domain vector of Vernier-1 that were acquired during the downstream burst (preamble and optionally pilots carriers) will be queried later by the BS through the BLM-REQ message.

11. The CPE will send these values (1680 I&Q values coded in 8 bits) to the BS when time allows.

12. Once the Vernier-1 vector is acquired by the BS, signal processing can be performed off-line. The precise delay (ns) of the first channel echo relative to the synchronization reference at the CPE can be extracted.

< BLM-RSP

BLM-REQ >

TTG TCPE

A1T2

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


BS

Vernier-1

Vernier-2

T1 CPEDownstream

Upstream

13. BS knows:TTG in TU’s (e.g., 1439 TU for 6 MHz),

T2 in symbols from the scheduling of the ranging burst: n* ((1+CP)*2048 TU),TCPE representing the precise CPE time advance measured when the CPE is

co-located with the BS in ns, TCPE-A1 is the residual delay at the CPE.T1 from the stopped counter in TU,V1 from the processing of the acquired Vernier-1 vector in ns,V2 from the processing of the acquired Vernier-2 vector in ns.

14. All the information necessary to calculate the propagation time between BS and CPE is known down to a nanosecond accuracy:Ptime = T1 - (T2 + TTG) - (TCPE-A1)+V1 + V2 (ns)

Distance = c * Ptime/2 (m)

T2

TTG TCPE

A1

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Validation of the Vernier concept

Syncadvance IQ Vector

LTS

Frequency

...

IDFT

Time

QI

Time

Cyclic prefix

QI

QI

QI

Time

2048 samples

QI

DFT

LTS distortedby channel

Frequency

...

QI

QI

τ1

Dirac distortedby channel

Frequency

...

Carrier phase reversalbased on the LTS coding

QI

QI

QI

Convolution with channelimpulse response

QI

IDFT

Complex channel impulse response relativeto the receiver synchronization time

QI

Sampling time

Imaginary

Re

al

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


Complexcorrelation

Channel impulse responserelative to the sampling time

τ 1

τ 2τ 3

Amplitude1 Delay1Amplitude2 Delay2Amplitude3 Delay3Amplitude4 Delay4 etc...

2048 I&Q samples at samplingperiod (i.e., every 145.86 ns)

High resolution bandlimited impulse response

(e.g., every 0.81 ns)

QI

2048 x 180 I&Q samplesat every 0.81 nsQI

-1

01

Precise time sampleImaginary

Rea

l

-1

0

1

I

Q


Sampling times

ImaginaryR

eal

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

802.22 OFDM Subcarrier Set

0-1-840 +840+1Subcarrier index

Am

pli

tud

e

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Prototype function construction

6000

7000

80009000

10000

-1

-0.5

0

0.5

1-1

-0.5

0

0.5

1

Precise time sample

LTS prototype function

Imaginary

Rea

l

145.8 ns

Stimulus

=145.86/180= 0.81 ns

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


6000

7000

80009000

10000

-1

-0.5

0

0.5

1-1

-0.5

0

0.5

1

Precise time sample


Imaginary

Rea

l

145.8 ns

Stimulus

=145.86/180= 0.81 ns

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


60007000

80009000

10000

-1

-0.5

0

0.5

1-1

-0.5

0

0.5

1

Precise time sample


Imaginary

Rea

l

145.8 ns

Stimuli

=145.86/180= 0.81 ns

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


60007000

80009000

10000

-1

-0.5

0

0.5

1-1

-0.5

0

0.5

1

Precise time sample


Imaginary

Rea

l

=145.86/180= 0.81 ns

145.8 ns

Stimuli

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


60007000

80009000

10000

-1

-0.5

0

0.5

1-1

-0.5

0

0.5

1

Precise time sample


Imaginary

Rea

l

=145.86/180= 0.81 ns

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


6000 6500 7000 7500 8000 8500 9000 9500 10000-1

0

1

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1LTS prototype function


Rea

l

=145.86/180= 0.81 ns

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


6000 6500 7000 7500 8000 8500 9000 9500 10000-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8


Precise time sample

Rea

l

=145.86/180= 0.81 ns

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


6000 6500 7000 7500 8000 8500 9000 9500 10000-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8


Precise time sample

Rea

l

145.8 ns

Stimulus

=145.86/180= 0.81 ns

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Re

al

-1

-0.5

0

0.5

Imaginary

1

6000 6500 7000 7500 8000 8500 9000 9500 10000

Precise time sample


=145.86/180= 0.81 ns

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


Complexcorrelation


τ 1

τ 2τ 3





QI


-1

01


Rea

l

-1

0

1

I

Q


Sampling times

ImaginaryR

eal

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Channel B

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Advanced and delayed responses

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Typical LTS generated multipath response

20 40 60 80 100 120 140 160 180 200-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time samples

Am

plit

ud

e

RealAbs

(1 sample = 145.86 ns)

SNR= 0 dB

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

50

100

150

200

-1

-0.5

0

0.5

1-1

-0.5

0

0.5

1

Time samples

LTS multipath response

Imaginary

Rea

l


(1 sample = 145.86 ns)

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


20 40 60 80 100 120 140 160 180 200-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time samples

Am

plit

ud

e

RealAbs

(1 sample = 145.86 ns)

SNR= 0 dB

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


5 10 15 20 25 30 35 40 45 50 55 60-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time samples

Am

plit

ud

e

RealAbs

(1 sample = 145.86 ns)

SNR= 0 dB

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


Complexcorrelation


τ 1

τ 2τ 3





QI


-1

01


Rea

l

-1

0

1

I

Q


Sampling times

ImaginaryR

eal

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Typical correlation output waveform

Precise time samples

Co

rrel

atio

n O

utp

ut A

mp

litu

de

0.5 1 1.5 2 2.5 3 3.5x 10

4-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

RealSamples

(1 sample = 145.86 ns)

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


1000 2000 3000 4000 5000 6000 7000 8000 9000 10000-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1


Co

rrre

lati

on

Ou

tpu

t A

mp

litu

de

RealSamples

(1 sample = 0.81 ns)

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

7500 8000 8500 9000 9500

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

Correlation Response


Rea

l and

Im

agin

ary

Am

plitu

des

Imag Real Samples



March 2010


doc.: IEEE 802.22-10/0054r0

Submission

8763 8764 8765 8766 8767 8768 8769 8770 8771

0.3932

0.3934

0.3936

0.3938

0.394

0.3942

0.3944

0.3946

0.3948

0.395

Correlation Response


Rea

l and

Im

agin

ary

Am

plitu

des

Imag Real Samples



March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Multipath results summary

SNR (dB) = (dB) 60 20 10 6 3 0 -3 -6 -10Micro-shift (1/10 sampling period) (ns) -43.758 -43.758 -43.758 -43.758 -43.758 -43.758 -43.758 -43.758 -43.758

Path #Relative

power (dB)Nominal

delay (us)Samples Delay (us) Delta (ns) Delta (ns) Delta (ns) Delta (ns) Delta (ns) Delta (ns) Delta (ns) Delta (ns) Delta (ns)

2 0 0 0 5.104 0.000 0.810 0.000 0.810 0.000 0.000 0.810 -1.620 3.2411 -6 -3 -21 2.042 -0.810 -0.810 -1.620 -0.810 -1.620 0.810 -3.241 3.241 -8.9123 -7 2 14 7.146 -0.810 0.000 -0.810 0.000 0.000 0.000 -0.810 -4.051 2.4315 -16 7 48 12.104 0.810 1.620 1.620 -1.620 -0.810 9.722 -5.671 2.431 8.9126 -20 11 75 16.042 -1.620 -1.620 -2.431 2.431 -8.102 -4.051 4.861 22.685 -23.495

Wrong echoes: 1 1 1 2 4 7 84 -22 4 27 9.042 -4.861 -5.671 -11.343 -10.532 -4.051 -27.546 -17.014 9.722 1382.176

SNR (dB) = (dB) 60 20 10 6 3 0 -3 -6 -10Micro-shift (1/10 sampling period) (ns) 0 0 0 0 0 0 0 0 0

Path #Relative

power (dB)Nominal


2 0 0 0 5.104 0.810 0.810 0.810 0.810 0.000 0.810 -0.810 2.431 -0.8101 -6 -3 -21 2.042 -0.810 -0.810 -0.810 0.000 -3.241 -2.431 2.431 -2.431 4.0513 -7 2 14 7.146 -0.810 0.000 -0.810 -0.810 -1.620 0.000 2.431 4.861 7.2925 -16 7 48 12.104 0.810 1.620 1.620 3.241 -3.241 -3.241 -3.241 -181.481 20.2556 -20 11 75 16.042 -1.620 -3.241 0.000 -3.241 8.912 -1.620 -29.977 8.102 -330.556

Wrong echoes: 1 1 1 1 7 84 -22 4 27 9.042 -4.861 -3.241 -0.810 -8.102 1.620 -4.051 -9547.222 9583.681 -5045.023

SNR (dB) = (dB) 60 20 10 6 3 0 -3 -6 -10Micro-shift (1/10 sampling period) (ns) 43.758 43.758 43.758 43.758 43.758 43.758 43.758 43.758 43.758

Path #Relative

power (dB)Nominal


2 0 0 0 5.104 0.810 0.000 0.810 0.000 0.000 0.000 1.620 0.000 0.8101 -6 -3 -21 2.042 -0.810 -0.810 0.000 -0.810 -0.810 1.620 -1.620 0.810 1.6203 -7 2 14 7.146 0.000 -0.810 -1.620 -2.431 0.000 1.620 -7.292 3.241 0.8105 -16 7 48 12.104 0.810 0.810 2.431 1.620 2.431 8.102 -4.051 -480.440 -20.2556 -20 11 75 16.042 -0.810 -2.431 3.241 -0.810 -4.861 -3.241 0.000 -0.810 0.000

Wrong echoes: 1 3 7 8 54 -22 4 27 9.042 -4.861 -5.671 -11.343 1.620 -12.153 -7198.495 -9765.972 3064.931 3.241

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


1000 2000 3000 4000 5000 6000 7000 8000 9000 10000-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1


Co

rrre

lati

on

Ou

tpu

t A

mp

litu

de

RealSamples


Wrong echo

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Multipath results summary (cont’d)

SNR (dB) = (dB) 60 20 10 6 3 0 -3 -6 -10Micro-shift (1/10 sampling period) (ns) -72.93 -72.93 -72.93 -72.93 -72.93 -72.93 -72.93 -72.93 -72.93

Path #Relative

power (dB)Nominal


2 0 0 0 5.104 0.810 0.000 0.000 0.000 0.810 0.810 1.620 2.431 1.6201 -6 -3 -21 2.042 -0.810 -0.810 -0.810 -0.810 -1.620 -1.620 -0.810 0.000 5.6713 -7 2 14 7.146 -0.810 -0.810 0.000 -1.620 0.000 -0.810 2.431 0.810 -6.4815 -16 7 48 12.104 0.810 0.810 -1.620 0.810 -1.620 -1.620 -5.671 36.458 6.4816 -20 11 75 16.042 -1.620 -1.620 -4.051 0.810 -4.051 -4.051 -2.431 -8.912 -1.620

Wrong echoes: 1 1 2 5 2 8 94 -22 4 27 9.042 -4.861 -4.861 -0.810 -8.912 -20.255 15.394 -682.986 18035.532 -638.426

SNR (dB) = (dB) 60 20 10 6 3 0 -3 -6 -10Micro-shift (1/10 sampling period) (ns) 0 0 0 0 0 0 0 0 0

Path #Relative

power (dB)Nominal


2 0 0 0 5.104 0.810 0.810 0.810 0.810 0.000 0.810 -0.810 2.431 -0.8101 -6 -3 -21 2.042 -0.810 -0.810 -0.810 0.000 -3.241 -2.431 2.431 -2.431 4.0513 -7 2 14 7.146 -0.810 0.000 -0.810 -0.810 -1.620 0.000 2.431 4.861 7.2925 -16 7 48 12.104 0.810 1.620 1.620 3.241 -3.241 -3.241 -3.241 -181.481 20.2556 -20 11 75 16.042 -1.620 -3.241 0.000 -3.241 8.912 -1.620 -29.977 8.102 -330.556

Wrong echoes: 1 1 1 1 7 84 -22 4 27 9.042 -4.861 -3.241 -0.810 -8.102 1.620 -4.051 -9547.222 9583.681 -5045.023

SNR (dB) = (dB) 60 20 10 6 3 0 -3 -6 -10Micro-shift (1/10 sampling period) (ns) 72.93 72.93 72.93 72.93 72.93 72.93 72.93 72.93 72.93

Path #Relative

power (dB)Nominal


2 0 0 0 5.104 0.000 0.000 0.000 1.620 0.810 1.620 0.810 0.000 0.0001 -6 -3 -21 2.042 -0.810 -0.810 -0.810 -2.431 -1.620 -4.051 0.810 0.000 1.6203 -7 2 14 7.146 -0.810 0.000 -0.810 0.000 -0.810 0.000 -2.431 3.241 -1.6205 -16 7 48 12.104 0.810 0.810 1.620 2.431 -1.620 3.241 -0.810 -12.153 -12.9636 -20 11 75 16.042 -0.810 0.000 -8.102 -2.431 -5.671 -2.431 4.861 21.065 8708.681

Wrong echoes: 1 1 1 2 2 5 2 54 -22 4 27 9.042 -4.861 -4.051 -3.241 12.963 -0.810 -5.671 1088.079 448.843 -6167.940

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Lab measurement setup

PN-sequencegenerator

LTSsequence

construction

2048-point

ifft

512-pointCyclicPrefix

addition

AgilentESG4438C

signal generator

AgilentN9020A MXAVector Signal

Analyzer

Samplingfrequencyconverter

Ethernetinterface

MATLAB

I&Q Channel impulseresponse estimate

LTSSignatureremoval

CyclicPrefix

RemovalCorrelator

MATLAB

Ethernetinterface

Signal generationand modulation

AgilentReferenceOscillator

Calibratedmultipathand noise

HP 11759CChannel

Simulator

UHF TVchannel

ifft fft

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

LTS-H I&Q Vector for analysis

Samples

Vec

tor

Am

pli

tud

e (A

BS

)

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Precise channel impulse after correlation with prototype function

enlever

Co

rre

lati

on

re

sp

on

se

1000 2000 3000 4000 5000 6000 7000 8000 9000 10000-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Precise time samples (1 sample= 0.81 ns)

Correlation output

Impulse response samples

4.950231 usec sync advance

2.997847 usec

Error= 2.15 ns

Pre-echo= 3 usec

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Subcarrier patterns for geolocation

Downstream:• Frame preamble

Long training sequence: 840 subcarriers (one every two)Time interval: 149.4 usec (Can easily absord all multipaths)

Upstream:• CDMA Ranging burst

Burst on 2 sub-channels: 56 subcarriers (one every 30)Time interval: 9.96 usec (Cannot absord all multipaths)

Burst on 2 sub-channels: 56 subcarriers unevenly spread (one every 10)Time interval: 29.87 usec (Can absord all multipaths)Reduced time localization of the Prototype functionNeed a search for the best spread for best localization.

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

50 100 150 200 250 300 350 400 450 500-60

-50

-40

-30

-20

-10

0

Time samples

Re

lativ

e A

mp

litu

de

(d

B)

56-carrier prototype function localization

29.87 usec(1 sample = 58.3 ns)

Poor selection

168

-car

rier

fu

nct

ion

56-c

a rri

e r f

un

ctio

n

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

56-carrier prototype function localization

29.87 usec(1 sample = 58.3 ns)

Better selection

168

-car

rier

fu

nct

ion

56-c

a rri

e r f

un

ctio

n

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

Propagation time between CPEs(Fine Time Difference of Arrival: TDOA)

BS

Vernier-1

Vernier-2

T1

CPE

1

Downstream

Upstream

1. BS signals the presence of a SCW in the upstream burst of the current frame using its upstream map (§6.10.4.1). It signals which CPEs will be in active mode (UIUC= 0) to transmit the CBP burst and which CPEs will be in passive mode (UIUC= 1, sync mode= 0) to listen and capture the CBP burst keeping their current synchronization (§6.10.4.1, comment #351).

2. BS sends a RNG-RSP message to both active and passive CPEs involved in the CPE-to-CPE ranging (could also be done in previous or following frames).

3. Upon arrival of the RNG-RSP request, CPEs will start their vernier-1 as described before (slides #4, 6 and 8) and capture the I&Q values of the reference carriers from the current frame preamble (and optionally pilot carriers) and respond with the RNG-REQ bursts in the slots allocated.

T2

Vernier-3 CPE

2

CBP burstTTG TCPE

TCPE

Vernier-1

A1

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


BS

Vernier-1

Vernier-2

T1

CPE

1

Downstream

Upstream

4. CPE-1 in active mode will then initiate the CBP burst transmission containing its identification (§6.8.1.2.1.7) at the start of the second symbol of the SCW

5. CPE-2 in passive mode and sync mode 0 will capture the CBP burst and start vernier-3 to acquire the I&Q values of the reference carriers from the CBP preamble (and optionally pilot carriers) to help recover the precise time at which the CBP burst has arrived at the CPE-2.

6. The BS will query the CPE-1 for its I&Q vectors acquired by its vernier-1 to carry out the precise BS-CPE ranging process off-line.

7. The BS will query the CPE-2 for its I&Q vectors acquired by its vernier-1 to carry out the precise BS-CPE ranging process off-line.

T2

Vernier-3 CPE

2

CBP burstTTG TCPE

TCPE

Vernier-1

A1

March 2010


doc.: IEEE 802.22-10/0054r0

Submission


BS

Vernier-1

Vernier-2

T1

CPE

1

Downstream

Upstream

8. The BS will then query the CPE-2 for its I&Q vector acquired by vernier-3. The propagation paths between the CPEs can now be calculated off-line.

9. The BS, or a terrestrial geolocation server, can then use the channel inpulse responses acquired in item 6, 7 and 8 to validate the line-of-sight propagation distances on each of the three paths despite possible multipath between the BS and the CPEs involved in the ranging process (e.g., identify the most reliable first echo and discarding calculations based on those that do not have a clear first path that would closely correspond to a line-of-sight condition).

10. The BS, or a terrestrial geolocation server, can then carry out triangulation based on reliable propagation paths to geolocate the CPEs using known waypoints (BS and some specific CPEs).

T2

Vernier-3 CPE

2

CBP burstTTG TCPE

TCPE

Vernier-1

A1

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

References1. IEEE P802.22™/ DRAFTv2.0 Draft Standard for Wireless Regional Area Networks

Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Policies and procedures for operation in the TV Bands, May 2009

2. 22-06-0206-00-0000-ranging-with-ofdm-systems.ppt

3. Krizman, K.J.; Biedka, T.E.; Rappaport, T.S.; ”Wireless position location: fundamentals, implementation strategies, and sources of error”, Vehicular Technology Conference, 1997 IEEE 47th Volume 2, 4-7 May 1997 Page(s):919 - 923 vol.2, Digital Object Identifier 10.1109/VETEC.1997.600463

4. 22-06-0141-00-0000_Locator_Presentation 802_22 July2006.pdf

5. Gustafsson, F.; Gunnarsson, F.; "Mobile positioning using wireless networks: possibilities and fundamental limitations based on available wireless network measurements", Signal Processing Magazine, IEEE, Volume 22, Issue 4, July 2005 Page(s):41 – 53

6. Reed, J.H.; Krizman, K.J.; Woerner, B.D.; Rappaport, T.S.; “An overview of the challenges and progress in meeting the E-911 requirement for location service”, Communications Magazine, IEEE Volume 36, Issue 4, April 1998 Page(s):30 - 37

7. Hepsaydir, E.; ‘Mobile positioning in CDMA cellular networks”, Vehicular Technology Conference, 1999. VTC 1999 - Fall. IEEE VTS 50th, Volume 2, 19-22 Sept. 1999 Page(s):795 - 799 vol.2

March 2010


doc.: IEEE 802.22-10/0054r0

Submission

References (cont’d)

8. Schmidl, T.M.; Cox, D.C;”Robust frequency and timing synchronization for OFDM”, Communications, IEEE Transactions on Volume 45, Issue 12, Dec. 1997 Page(s):1613

9. Minn, H.; Zeng, M.; Bhargava, V.K.; "On timing offset estimation for OFDM systems", Communications Letters, IEEE Volume 4, Issue 7, July 2000 Page(s):242 – 244

10. Morelli, M.; Mengali, U.; "An improved frequency offset estimator for OFDM applications", Communication Theory Mini-Conference, 1999, 6-10 June 1999 Page(s):106 - 109

11. Mensing, C.; Plass, S.; Dammann, A.; ”Synchronization Algorithms for Positioning with OFDM Communications Signals”, Positioning, Navigation and Communication, 2007. WPNC '07,. 4th Workshop 22-22 March 2007. Page(s):205 – 210

12. Fredrick S. Solheim1, Jothiram Vivekanandan1, Randolph H. Ware, Christian Rocken; "Propagation Delays Induced in GPS Signals by Dry Air, Water Vapor, Hydrometeors and Other Particulates", Journal of Geophysical Research,104, 9663-9670, 1999

13. http://www.kowoma.de/en/gps/errors.htm

doc.: ieee 802.22-10/0054r0 submission march 2010 gerald chouinard, crcslide 1 ofdma-based...

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