November 2004 doc.: IEEE 802. 15-04-0380-02-004a · 2011-07-13 · Submission Slide 2 D. I. Kim, S....

D. I. Kim, S. Erküçük, K. S. KwakSubmission Slide 1

November 2004 doc.: IEEE 802. 15-04-0380-02-004a

Project: IEEE P802.15 Working Group for Wireless Personal Area NProject: IEEE P802.15 Working Group for Wireless Personal Area Networks (etworks (WPANsWPANs))

Submission Title: M-ary Code Shift Keying/Binary PPM (MCSK/BPPM) Based Impulse RadioDate Submitted: November 22, 2004Source: [Dong In Kim (1), Serhat Erküçük (1), Kyung Sup Kwak (2)]

Company: [(1) Simon Fraser University (2) UWB-ITRC, Inha University]Address: [(1) School of Engineering Science, 8888 University Drive, Burnaby, BC

V5A 1S6, Canada (2) 253 Yonghyun-Dong, Nam-Gu, #401, Venture Bldg.Incheon, 402-751 Korea]

Voice: [+1 (604) 291-3248], Fax: [(1) +1 (604) 291-4951 (2) +82-32-876-7349]E-Mail: [(1) [email protected] (2) [email protected]]

Abstract: [This document proposes preliminary proposal for the IEEE 802.15.4 alternate PHY standard]

Purpose: [Preliminary Proposal for the IEEE802.15.4a standard]Notice: This document has been prepared to assist the IEEE P802.15. 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 acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15



Preliminary Proposal for IEEE 802.15.4a Alternate PHY

M-ary Code Shift Keying/Binary PPM(MCSK/BPPM) Based Impulse Radio

SFU, Canada & UWB-ITRC, Inha UniversityRepublic of Korea



Contents

• TG4a Requirements• MCSK/BPPM• PHY TX Structure• TH Code Assignment• Transceiver Architecture• Information Rate• Location Accuracy• Conclusion



TG4a Requirements

No new circuit is needed / simple transceiver structurelow complexity and cost

Lower transmit power at the same/higher information rates and better BER performance

low power consumption

Improved ranging/locationprecision capability

high precision ranging/ location

Better BER performance at the same/higher information rates and lower transmit power

scalable information rates

MCSK/BPPM compared to TH-PPM802.15.4a PHY

*MCSK/BPPM: M-ary Code Shift Keying/Binary Pulse Position Modulation**TH-PPM: Time Hopping Pulse Position Modulation



MCSK/BPPMTH PPM – user #1

[ ]...101011d )1( =

MCSK/BPPM – user #1

1 user specific TH codeTH-BPPM

bT2bT0 bT3t

1 1 0 1

[ ]...101011d )1( =

M user specific TH codes

TH-BPPMchoosea code

1 TH code

110 101 …

M=4

c3

TX

only for multiple access

for multiple access and data modulation

MCSK: M-ary Code Shift KeyingBPPM: Binary Pulse Position Modulation

bT2bT0 bT3t

:bT:fT

Bit timeFrame time



M user specific TH codes- TH codes are periodic with Np- each pulse should be repeated Ns times- Np/Ns=k is an integer

⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢

⎣

⎡

=

⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢

⎣

⎡

=

15736842624137851478256351463287

cccc

3

2

1

0

TH[ ]...1101=d

4,8,4 === sp NNMExample:

fT20t

fT fT8

C2 5 8 7 3 1 4 2 6

PHY TX Structure (1/2)

MCSK

[ ]...1101=d

BPPM

fT3 fT4 fT5 fT6 fT7

bT bT20

TX

:bT:fT

Bit timeFrame time



PHY TX Structure (2/2)M user specific TH codes

- TH codes are periodic with Np- each pulse should be repeated Ns times- Np/Ns=k is an integer

Information rate vs. BER performance for fixed Ns and varying Np and M

bT

0bT

4

1/

=

=

M

NsN p

8

1/

=

=

M

NsN p

8

2/

=

=

M

NsN p

Scenario Time domain illustration Info.rate

BER performance

1 bit (BPPM)

2 bits (MCSK)

1 bit (BPPM)

3 bits (MCSK)

1 bit (BPPM)

3 bits (MCSK)

bT bT20

1 bit (BPPM)

Np/Ns same

M increasing

Np/Ns increasing

M same

TX

:bT :fTBit time Frame time

0



M user specific TH codesEach user has MNN pu sample-long sequence?NO!Generation of TH codes – “Case 1: random assignment”

[ ]...001010100010111011001010011101

64,6;2 ==≡ hhl NlN

m-sequence:

0 fTFor Tf = 100ns, Tc = 1ns:100 slots for multiple access

46 20 55

c0

c1

c2c3

user #1

c0

c1

c2c3

user #2

( )1−+⇒ MNNNN pupu

[ ]...235455326247556146131121320175520464

4

=

=

M

N p

TH Code Assignment (1/2) TX



TH Code Assignment (2/2)

[ ]...23545532624755614613112132017552046

[ ]17552046

[ ]20175520[ ]13201755

[ ]12132017[ ]31121317

[ ]5561461

user #2

Generation of TH codes – “Case 2: no overlapping”

4

4

=

=

M

N p

user #1 user #2 user #k. . .

user #1

no collisions allowed within user codes

( ) nMNNNN pupu +−+⇒ 1n: number of overlaps

TX



General Modulation Format

• Extra information• Random selection of

TH codes Smooth spectrum

• Fixed signal space• Increased information rate

RNNMR

sps ⋅⎟

⎟⎠

⎞⎜⎜⎝

⎛+=

/log1 2

TX



Receiver Structure - MLSE

M

Np/Ns

( )Msp NN /2computation complexity

template signals2M

M

Mhardware structure

correlators

RX



Information Rate (1/2)

fT0 fT 2

fT0 fT 2

fT0 fT 2

fT ′0 fT ′2

TH-BPPMNs = 2, M=1

MCSK/BPPM “Constant Energy/Bit” Constraint

Ns = 2, Np=2, M=2

MCSK/BPPM“Constant Power” Constraint

Ns = 2, Np=2, M=2

RNNMR

sps ⋅⎟

⎟⎠

⎞⎜⎜⎝

⎛+=

/log1 2

MCSK/BPPM (same info. rate)“Constant Power” Constraint

Ns = 2, Np=2, M=2

A

A

A’

A’

fsp

f

sp

TNNMT

ANNMA

⎟⎟⎠

⎞⎜⎜⎝

⎛+=′

+=′

/log1

/log1

2

2

Info. rate Rs R

2R

2R

R

can be adjusted to achieve higher information rate at lower transmit power and still maintain better BER performance at the same time



Information Rate (2/2)

Scalable info. rates

0 ff TT 4=′

A’=2A

fT2fT fT3

0

A

fT

0 fT4

A’=1.58A

fT2fT fT3

0

A

fT fT2

ff TT 52 =′

0 fT4

A’=1.41A

ff TT 2=′fT fT3

0

A

fT fT2

fT5 fT6

fT3

MCSK/BPPM “Constant Power”Constraint for Ns = 1, M=8

fT ′

1=s

p

NN

2=s

p

NN

3=s

p

NN

4R R

2.5R R

2R R

BER performance(wrt TH-PPM)

- same collusion effects- no processing gain- no improvement

- same collusion effects- processing gain- improved BER- TX power can be lowered- info rate can be increased

fsp

f

sp

TNNMT

ANNMA

⎟⎟⎠

⎞⎜⎜⎝

⎛+=′

+=′

/log1

/log1

2

2

RNNMR

sps ⋅⎟

⎟⎠

⎞⎜⎜⎝

⎛+=

/log1 2



Location AccuracyProcedure Result Comment

Step 0

Step 1

Step 3

Step 2

Step 4

Increase M

Increase Np/Ns

Increase T’f

Increase A’

Initial conditionsfor TH-PPM

01

01

01

;;

TXTXBERBER

RR

=>

>

R0 (information rate); BER0 (performance)TX0 (power)

02

21

021

;;

TXTXBERBER

RRR

=>>>

BER2 may or may not beless than BER0

30

32

0321

;;

TXTXBERBER

RRRR

>>

>>> BER3 may or may not beless than BER0

340

4043

034

;&;

TXTXTXBERBERBERBER

RRR

>>>>

>= Increased frame time with longer observation period,higher information rate, better BER performance and lower transmit power

Accurate Ranging/Location

MCSK/BPPM“Constant Power” Constraint



Conclusion

• MCSK/BPPM provides:increased information ratelower transmit powerbetter BER performanceimproved spectral characteristics

• MCSK/BPPM is capable of:information rate scalabilitylocation/ranging accuracy

Simultaneously!

IEEE 802.15.4a PHY



Back-up Slides



MCSK/BPPM

“Constant Energy/Bit” Constraint

0 2 4 6 8 10 12 14 16 18 20

10-4

10-3

10-2

10-1

100Bit-Error-Rate for Np/Ns=1 (same energy per bit)

SNR (dB)

BE

R

M=2M=4conventional

0 2 4 6 8 10 12 14 16 18 20

10-4

10-3

10-2

10-1

100

SNR (dB)B

ER

Bit-Error-Rate for Np/Ns=2 (same energy per bit)

M=2M=4M=8conventional



MCSK/BPPM

“Constant Power” Constraint

0 2 4 6 8 10 12 14 16 18 2010-5

10-4

10-3

10-2

10-1

100

SNR (dB)

BE

R

Bit-Error-Rate for Np/Ns=2


0 2 4 6 8 10 12 14 16 18 2010-5

10-4

10-3

10-2

10-1

100

SNR (dB)

BE

R



0 2 4 6 8 10 12 14 16 18 2010

-5

10-4

10-3

10-2

10-1

100

SNR (dB)

BE

R





MCSK/BPPM

“Constant Power” Constraint

Improved performance at the same information rate for M=8

0 2 4 6 8 10 12 14 16 18 2010-5

10-4

10-3

10-2

10-1

100

SNR (dB)

BE

RM=8, same information rate for the same power constraint

Np/Ns=1Np/Ns=2Np/Ns=3Np/Ns=4Np/Ns=5conventional



Effects of TH Code Design on the Performance

MCSK/BPPM “Constant Power” Constraint

0 2 4 6 8 10 12 14 16 18 2010-4

10-3

10-2

10-1

100

SNR (dB)

BE

R

Np/Ns=1, TH code comparison

M=4, rand.M=8, rand.M=4, det.M=8, det.conv.

0 2 4 6 8 10 12 14 16 18 2010-4

10-3

10-2

10-1

100

SNR (dB)B

ER

Np/Ns=2, TH code comparison

M=4, rand.M=4, det.conv.



0 1 2 3 4 5 6 7 8 9 10

x 108

1010

1011

1012

1013

1014

frequency (Hz)

code

spe

ctru

m

M=8, Np=10

M=256, Np=10

M=8, Np=256

0 1 2 3 4 5 6 7 8 9 10

x 108

1010

1011

1012

1013

1014

frequency (Hz)

code

spe

ctru

m

∞

TH Code Spectrum of:

a) TH-BPPM, Np=10

b) ideal MCSK/BPPM, Np

c) realistic MCSK/BPPM

Fig. b. ideal MCSK/BPPM Fig. c. realistic MCSK/BPPM

0 1 2 3 4 5 6 7 8 9 10

x 108

1010

1011

1012

1013

1014

frequency (Hz)

code

spe

ctru

m

ideal spectrum

Fig. a. TH-BPPM

November 2004 doc.: IEEE 802. 15-04-0380-02-004a · 2011-07-13 · Submission Slide 2 D. I. Kim, S....

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