1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
January 2005
doc.: IEEE /704r2
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANS)
Submission Title: [Staccato UWB PHY Proposal for TG4a]
Date Submitted: [January 2005]
Revised: [2]
Source: [Roberto Aiello, Ph.D., Torbjorn Larsson, Ph.D.] Company [Staccato Communications]
Re: [ a Call for proposal]
Abstract: [This presentation represents Staccato Communication’s proposal for the a PHY standard, based on UWB]
Purpose: [Response to WPAN a Call for Proposals]
Notice: This document has been prepared to assist the IEEE P 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 P
<author>, <company>

2. Staccato Communications UWB PHY Proposal for TG4a
January 2005
Staccato Communications UWB PHY Proposal for TG4a
Roberto Aiello, Ph.D.
Torbjorn Larsson, Ph.D.
Staccato Communications
Roberto Aiello, Staccato Communications

3. Goals Good use of UWB unlicensed spectrum Good system design
January 2005
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
Roberto Aiello, Staccato Communications

4. Introduction Staccato is MBOA’s founding member, promoter BOD member
January 2005
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
Roberto Aiello, Staccato Communications

5. Features Meets all system requirements
January 2005
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
Roberto Aiello, Staccato Communications

6. January 2005
Summary
Band limited UWB system compliant with FCC 02-48, UWB Report & Order
500MHz bandwidth at -10dB
Two bands centered at GHz and GHz (MB-OFDM band 4 and 5)
Data 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
Roberto Aiello, Staccato Communications

7. Multipath CM8 (Industrial NLOS) PRF = 3.2 MHz January 2005
Roberto Aiello, Staccato Communications

8. System Description January 2005 PRF = 3.2 MHz (Period = 312.5 ns)
Roberto Aiello, Staccato Communications

9. System Description, Continued
January 2005
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
Roberto Aiello, Staccato Communications

10. System Description, Continued
January 2005
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 a 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
Roberto Aiello, Staccato Communications

11. Differential Multipath Combining
January 2005
Differential Multipath Combining
Roberto Aiello, Staccato Communications

12. System Parameters Length of spreading code in preamble is always 16
January 2005
System Parameters
PHR = PHY Header; PSDU = PHY Service Data Unit; SFD = Start-of-Frame Delimiter
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
Roberto Aiello, Staccato Communications

13. January 2005
Packet Structure
Roberto Aiello, Staccato Communications

14. Spreading Codes (Length 16)
January 2005
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 differentially encoded code words (1,c) and (1,-c)
Roberto Aiello, Staccato Communications

15. January 2005
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
Roberto Aiello, Staccato Communications

16. Receiver Architectures
January 2005
Receiver Architectures A.
Differential chip detection during both acquisition and data demodulation B.
Differential chip detection during acquisition and non-coherent symbol detection during data demodulation
Roberto Aiello, Staccato Communications

17. More on Receiver Architectures
January 2005
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)
Roberto Aiello, Staccato Communications

18. January 2005
Link Budget
Roberto Aiello, Staccato Communications

19. System Simulation Parameters
January 2005
System Simulation Parameters
Frequency band: 4.752GHz (MB-OFDM band 4)
10 dB bandwidth: 500 MHz
Transmit power: 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
Roberto Aiello, Staccato Communications

20. Spectrum TX Power: -16.1 dBm January 2005
Roberto Aiello, Staccato Communications

21. PER vs. Distance in AWGN (100 kbps)
January 2005
PER vs. Distance in AWGN (100 kbps)
Roberto Aiello, Staccato Communications

22. PER vs. Eb/No (100 kbps) January 2005
Roberto Aiello, Staccato Communications

23. PER vs. Received Power (100 kbps)
January 2005
PER vs. Received Power (100 kbps)
Roberto Aiello, Staccato Communications

24. Conclusions UWB band limited system Meets all system requirements
January 2005
Conclusions
UWB band limited system
Meets all system requirements
Combination of impulse radio and DS spreading
Low pulse repetition frequency to reduce ICI and need for high speed digital circuits (lower power consumption)
“Narrow” UWB bandwidth to reduce complexity
Spreading codes designed to support both differential chip detection and non-coherent symbol detection
Remaining material will be presented at the next opportunity
Roberto Aiello, Staccato Communications

25. Staccato Communications is actively collaborating with others
January 2005
a Early Merge Work
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.
Roberto Aiello, Staccato Communications