1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [DecaWave Preliminary PHY Proposal]
Date Submitted: [9th July 2009]
Source: [Michael McLaughlin]
Company [DecaWave Limited]
Address [Digital Depot, Thomas Street, Dublin 8, Ireland]
Re : [Response to Call for Preliminary Proposals]
Abstract:[DecaWave Preliminary PHY Proposal]
Purpose:[Introduce IEEE f TG meeting attendees to DecaWave’s proposal for a PHY for
f active RFID]
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(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 P

2. DecaWave: Our Vision, Our Mission
“The Internet of Things”
A world where anybody or anything can locate and communicate with any other body or thing, made possible by pervasive, extremely low power, low cost, wireless transceivers.
Fabless IC Design Company
Silicon solutions for wireless transceivers targeting Asset Location, Tracking & Control and Consumer & Body Area Networking.

3. Phew! That was easier than I thought!
Proposal for f
Use UWB PHY from a- as the PHY layer for f
Add an RFID Packet Template
Mandatory 64 bit ID
Provision for optional additional ID
Provision for optional sensor + other user Data
Instead of 8GHz mandatory high band make either 6.5GHz or 8GHz mandatory for high band modes, depending on national availability.
Incorporate known a errata ( a a-2007-errata-DRAFT.doc)
Add one way, messaging capability to the MAC
Then We`re Done!
Phew! That was easier than I thought!

4. Summary of 802.15.4a- UWB Ultra-Wideband alternative PHY for 802.15.4
Lower power
Better multipath immunity
RTLS capable
Low and High Data Rates
Low data rates
Gets longer range
High Data rates
Allows shorter packets, very high tag density, even lower power
Bitrates
110kbps, 850kbps, 6.8Mbps, 27Mbps
Low and High Pulse Repetition Frequencies
4MHz, 15.6MHz, 62.4MHz
Modulation scheme
Burst position with BPSK
Can be decoded with OOK type receiver
FEC Scheme
Reed Solomon code
Systematic Convolutional Code
Simple to implement in the transmitter
Both of these can be ignored in the receiver

5. Summary of 802.15.4a- UWB cont. Ideal channel sounding preamble
Periodic autocorrelation is an impulse or kronecker delta function
Bandwidth
500MHz, 1100MHz or 1300MHz
Channels
15 frequency bands from 3GHz to 10GHz
Designed to be usable for one-way or two way ranging
Complexity choice for receiver
coherent or non-coherent demodulation
FEC can be ignored by receiver

6. Bandplan Facilitating WorldWide Deployment
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Frequency, MHz
Channel
Double-ended arrows
show allowed UWB frequency
bands in various regions.
LDC = low duty cycle
i.e. infrequent TX
Pink and purple
lines show the .4a defined
frequency channels
and bandwidths
USA (& now Canada)
USA indoors and out
Europe (& now China)
Europe with LDC
>50Mbps
Japan until 2009
Korea
Korea with LDC
.4a 500MHz
.4a >1GHz 6

7. Link Margin and Range

8. DecaWave’s .4a Channel Model
The curves below represent the mean and worst 10% attenuation plotted as a function of distance.
The red curves are for a signal with 20MHz bandwidth
The green curves are for a signal with 500MHz bandwidth
It can be seen that the wider bandwidth has much lower worst 10% attenuation 10 1 2 5 15 20 25 30 35 40 45 50
distance (meters)
Path Loss (dBs)
UWB Path Loss
Worst 10% of UWB Path Loss
Narrowband Path Loss
Worst 10% of Narrowband Path Loss
Attenuation of worst 10% of
channels at 10 meters 8

9. 802.15.4a Receive Signal Buried In Thermal Noise
.4a Receive 110kps and noise at -31dB SNR. This corresponds to a distance of 450 meters outdoors, 40 meters indoors
.4a Receive 6.8Mbps and noise at -11dB SNR. This corresponds to a distance of 60 meters outdoors, 17 meters indoors 9

10. Coherent or Non−Coherent Decode
IEEE a-UWB was designed to be used by either a coherent or non−coherent receiver
Some quotes from the published standard:
“The modulation used in the ultra−wide band (UWB) physical layer (PHY) that combines both binary phase−shift keying (BPSK) and pulse position modulation (PPM) so that both coherent and non−coherent receivers can be used to demodulate the signal.”
“the UWB PHY also provides a hybrid modulation that enables very simple, non−coherent receiver architectures to further minimize power consumption and implementation complexity.
“A combination of burst position modulation (BPM) and binary phase−shift keying (BPSK) is used to support both coherent and non−coherent receivers using a common signalling scheme. The combined BPM−BPSK is used to modulate the symbols, with each symbol being composed of an active burst of UWB pulses”

11. FEC and Symbol Structure

12. Channel Sounding Preamble
Example preamble sequence
− −1 +1 − − − −1
Non−coherent receiver only sees energy there or not i.e. 5 10 15 20 25 30 35 2 4 6 8 12 14 16
Periodic autocorrelation of preamble sequence

13. Non-coherent channel sounding5 10 15 20 25 30 35
Cross-correlation of Magnitude and Modified Preamble Sequence
This show the cross correlation of
With
i.e. 0 replaced by -1

14. IEEE 802.15.4a-UWB Ranging Options
Two way ranging option

15. IEEE 802.15.4a-UWB Ranging Options
IEEE a-UWB has the option of being transmit only
“The capabilities required to accomplish one−way ranging are sufficiently similar that this standard allows operation in that mode as well”
4a Tag

16. Summary
IEEE a-UWB is an extremely low complexity ultra wideband communications and RTLS Standard
Many companies and individuals with wide-ranging expertise worked on 4a
It has been scrutinised by many pairs of eyes
Non-coherent option enables ultra-low cost receiver implementations
Transmitter is already ultra low complexity
Transmitter is very easy to implement
Coherent receiver option allows much larger range
Complexity of RFID reader is usually less critical than tag
15.4f requires some backward compatible additions to support RFID