project: ieee p802.15 working group for wireless personal area networks (wpans) submission title:...

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANS)

Submission Title: [Staccato UWB PHY Proposal for TG4a]

Date Submitted: [January 2005]Revised: []

Source: [Roberto Aiello, Ph.D., Torbjorn Larsson, Ph.D.] Company [Staccato Communications] E-mail [[email protected]]

Re: [802.15.4a Call for proposal]

Abstract: [This presentation represents Staccato Communication’s proposal for the 802.15.4a PHY standard, based on UWB]

Purpose: [Response to WPAN-802.15.4a Call for Proposals]

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 or organization. The material in this document is subject to change in form and content after further study. The contributor reserves 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.

January 2005 doc.: IEEE 802.15-04/704r1

January 2005

Roberto Aiello, Staccato CommunicationsSlide 2

doc.: IEEE 802.15-04/704r1

Submission

Staccato CommunicationsUWB PHY Proposal for TG4a

Roberto Aiello, Ph.D.

Torbjorn Larsson, Ph.D.

Staccato [email protected]

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Goals

• Good use of UWB unlicensed spectrum

• Good system design

• Path to low complexity CMOS design

• Path to low power consumption

• Scalable to future standards

• Graceful co-existence with other services

• Graceful co-existence with other UWB systems

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Introduction

• Staccato is MBOA’s founding member, promoter BOD member

• This proposal is based on band limited impulse radio

• OFDM is optimal solution for high performance systems

• Impulse radio has attractive features for 15.4a applications

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Features

• Meets all system requirements

• Low signal repetition frequency to reduce ICI/ISI and need for high speed digital circuits (lower power consumption)

• “Narrow” UWB bandwidth to reduce complexity

• Use of differential encoding on chip level to reduce receiver complexity and provide maximum robustness

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Summary

• Band limited UWB system compliant with FCC 02-48, UWB Report & Order

• 500MHz bandwidth at -10dB

• Two bands centered at 4.752 GHz and 5.252 GHz (MB-OFDM band 4 and 5)

• Symbol rates varying from 12.5 kbps to 1.6 Mbps at PHY-SAP

• Due to time constraints, this presentation addresses– Modulation scheme, channelization and packet structure– Performance in AWGN

• Remaining material will be presented at the next opportunity in March 2005– Performance in multipath– Implementation feasibility– Self evaluation criteria– Other issues that will emerge from group’s feedback

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Multipath

0 100 200 300 400 500 6000

0.05

0.1

Time [ns]

Multipath Channel Output

CM8 (Industrial NLOS)

PRF = 3.2 MHz

January 2005


doc.: IEEE 802.15-04/704r1

Submission

System Description

DifferentialDetection

Codeword C or - C differentially encoded

DifferentialDetection

Add Coherently

Non-Coherent detection of differentially encoded

codewords (1,C) and (1,- C)

De-Spreading

PRF = 3.2 MHz

January 2005


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Submission

System Description, Continued

• Impulse radio combined with direct-sequence spreading

• Differential BPSK modulation of chips

• A code word covers one BPSK-modulated symbol

• Different piconets use different code words

• Differential encoding of chips allows the use of differential chip detection in the receiver– Differential detection is carried out separately for each multipath

component– Differential combining of multipath components– No need for channel estimation– Simple receiver structure with decent performance

January 2005


doc.: IEEE 802.15-04/704r1

Submission

System Description, Continued• For improved performance, non-coherent symbol detection (with

coherent energy integration across one code word) can be used– Symbol detection is carried out separately for each multipath

component

– Non-coherent combining of multipath components

– Still no need for channel estimation

• PRF (chip rate): 3.2 MHz– Low enough to avoid interchip interference (ICI) with all 802.15.4a

multipath models

– High enough to eliminate the need for frequency offset correction (with some performance loss) when differential detection is used

• Pulse shape: 3rd-order Butterworth or similar

• FEC: 16-state rate-1/2 convolutional code and symbol repetition

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Differential Multipath Combining

nx ,1nx ,2

nx ,3

1,1 nx 1,2 nx

1,3 nx

*,31,3

*,21,2

*,11,1 ReReRe nnnnnn xxxxxx

January 2005


doc.: IEEE 802.15-04/704r1

Submission

System Parameters

Data Rate [kbps] Length of spreading code in PHR and PSDU

Duty Cycle [%] Length of SFD in bits

12.5 16 12.5 32 25 16 25 32 50 16 50 32 100 16 100 32 200 8 100 16 400 4 100 8 800 2 100 5 1600 1 100 3

• Length of spreading code in preamble is always 16

• Duty cycle < 100% means that code words of length 16 are transmitted with a space in between

– An extra initial chip is added to serve as phase reference for the first chip in the code word

– For instance, to achieve a duty cycle of approximately 50%, 17 chips are transmitted followed by a space equivalent to 15 chip periods

PHR = PHY Header; PSDU = PHY Service Data Unit; SFD = Start-of-Frame Delimiter

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Packet Structure

400 kbps

Preamble192 chips

SFD128 chips

PHR48 symbols

PSDU(LENGTH*8+4)*2 symbols

1 symbol = 4 chips

200 kbps

Preamble384 chips

SFD256 chips

PHR48 symbols


1 symbol = 8 chips

Preamble768 chips

SFD512 chips

PHR48 symbols


100 kbps

1 symbol = 16 chips

800 kbps

Preamble96 chips

SFD80 chips

PHR48 symbols


1 symbol = 2 chips

1600 kbps

Preamble48 chips

SFD48 chips

PHR48 symbols


1 symbol = 1 chip

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Spreading Codes (Length 16)

-1 -1 1 -1 -1 1 -1 1 -1 -1 -1 1 1 1 1 1

-1 1 -1 1 -1 -1 1 1 -1 -1 -1 -1 1 1 1 1

-1 1 1 -1 1 -1 -1 -1 -1 -1 1 1 1 -1 1 1

-1 -1 -1 -1 -1 1 1 1 1 -1 1 1 -1 1 -1 1

These code words (c) were found by exhaustive search based on the three following properties:

–Low cyclic autocorrelation–Low cyclic cross-correlation between code words c–Low cross-correlation between code words (1,c)

and (1,-c)

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Throughput

• The length of the data PSDU (payload) is 32 octets. The data rate is 100 kbps (this is X0 in this proposal)

• Assumptions (refer to the figure on page 20 in the PHY selection criteria document)– aMinLIFSPeriod = 40 symbol periods – aTurnaroundTime = 12 symbol periods – aUnitBackoffPeriod = 20 symbol periods – Length of ACK PSDU = 5 octets

• t_ack is the time between the end of the data frame and the beginning of the ACK frame– worst case, is t_ack = aTurnaroundTime + aUnitBackoffPeriod = 32 – best case, t_ack is t_ack = aTurnaroundTime = 12

Data Rate [kbps] Worst-Case Throughput [kbps] Best-Case Throughput [kbps] 1600 875.2 894.3 800 437.6 447.2 400 218.8 223.6 200 109.4 111.8 100 54.7 55.9 50 27.4 27.9 25 13.7 14.0 12.5 6.8 7.0

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Receiver Architectures

LPFX

LOLNA/VGA

Timing

X LPF ADC

ADC

DiffDetection

MultipathCombing

DSDe-Spread

SymbolCombining

ViterbiDecoding

AcquisitionGain

Differential chip detection during acquisition and non-coherent symbol detection during data demodulation

Differential chip detection during both acquisition and data demodulation

A.

B.LPFX

LOLNA/VGA

Timing

X LPF ADC

ADCDiff

DetectionMultipathCombing

DSDe-Spread

SymbolCombining

ViterbiDecoding

Acquisition

Non-CoherentDetection

MultipathCombining

(Across one DS codeword)

Gain

FrequencyCorrection

Data

Freq Offset

January 2005


doc.: IEEE 802.15-04/704r1

Submission

More on Receiver Architectures

• In both architectues, acquisition is based on differential detection/combining– Does not require frequency offset correction and therefore leads to shorter

preamble (=> less overhead)– Small performance loss at 20 ppm frequency error– If desired, frequency offset estimation can be carried out in parallel with

synchronization

Architecture A • Differential chip detection for data demodulation

– Frequency offset correction may still be applied during PHR and PSDU to improve performance

Architecture B.• Non-coherent symbol demodulation for data demodulation

– Significant performance improvement, since we are now summing energy coherently across a whole codeword (which for data rates <= 100 kbps is 16 chips long)

– Requires frequency offset estimation (during acquisition) and correction (during data demodulation)

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Link Budget

Bit Rate 100,000 bpsTX Bandwidth 500 MHzTX Power -16.1 dBmCenter frequency 4,752,000,000 HzPath Loss at 1m 45.98 dBReference distance 100 m Path Loss Distance 40 dBRX Antenna Gain 0 dBiRX Power -102.08 dBmNoise Figure 7 dBNo -167 dBm/HzRequired Eb/No 11.5 dBImplementation Loss 0.5 dBLink Margin 3.42 dBZero Margin Range meters 148.26 m

January 2005


doc.: IEEE 802.15-04/704r1

Submission

System Simulation Parameters

• Frequency band: 4.752GHz (MB-OFDM band 4) • 10 dB bandwidth: 500 MHz • Transmit power: -16.1 dBm • Transmit/Receive filter: 3rd order Butterworth, corner frequency 180 kHz • A/D converter: 528 MHz, 3 bits• Noise figure: 7 dB • Data rate: 100 kbps • PSDU size: 32 bytes • PRF (chip rate): 3.2 MHz • Length of DS spreading code: 16 • Length of preamble: 48 bits • Length of SFD: 32 bits • Length of PHR: 48 bits • Modulation: DBPSK • Demodulation method: differential detection • No frequency offset

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Spectrum

4 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 6-80

-75

-70

-65

-60

-55

-50

-45

-40

GHz

dB

m

Power over 1 MHz Bandwidth

ProposalFCC Mask

TX Power: -16.1 dBm

January 2005


doc.: IEEE 802.15-04/704r1

Submission

PER vs. Distance in AWGN (100 kbps)

120 130 140 150 160 170 180 190 200 210 22010

-4

10-3

10-2

10-1

100

AWGN Channel

Distance [m]

PE

R

January 2005


doc.: IEEE 802.15-04/704r1

Submission

PER vs. Eb/No (100 kbps)

8 9 10 11 12 13 1410

-4

10-3

10-2

10-1

100

AWGN Channel

Eb/N

0 [dB]

PE

R

January 2005


doc.: IEEE 802.15-04/704r1

Submission

PER vs. Received Power (100 kbps)

-109 -108 -107 -106 -105 -104 -10310

-4

10-3

10-2

10-1

100

AWGN Channel

Received Power [dBm]

PE

R

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Conclusions

• UWB band limited system

• Meet all system requirements

• Low signal repetition frequency to reduce ICI and need for high speed digital circuits (lower power consumption)

• “Narrow” UWB bandwidth to reduce complexity

• Remaining material will be presented at the next opportunity

January 2005


doc.: IEEE 802.15-04/704r1

Submission

Staccato Communications is actively collaborating with others

Objectives:

• “Best” Technical Solution • ONE Solution • Excellent Business Terms• Fast Time To Market

We encourage participation by any party who can help us reach our goals.

802.15.4a Early Merge Work

project: ieee p802.15 working group for wireless personal area networks (wpans) submission title:...

Documents

staccato communicationsslide

04704r1 submission

04704r1 slide

tg4a roberto aiello

introduction staccato

staccato uwb phy proposal

ieee p802

property of ieee