1. May, 2010
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: Long-range mode preamble design for f UWB PHY
Date Submitted: 18th May 2010
Source: Andy Ward, Ubisense
Address: St Andrew’s House, St Andrew’s Road, Chesterton, Cambridge, CB4 1DL, ENGLAND
Voice: , FAX: ,
Abstract: Design of preamble for long-range mode of f UWB PHY
Purpose: To be considered by TG4f
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.
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Andy Ward, Ubisense

2. Design of long-range mode preamble
May, 2010
Design of long-range mode preamble
Andy Ward
Ubisense
Andy Ward, Ubisense

3. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May, 2010
Overview
There are a number of requirements that we wish to meet for a long-range mode preamble design:
Needs a signal acquisition phase, so coherent receiver can pick signal out of noise
Needs a method of assisting base-mode receivers with detection and decoding of the long-range mode packets
Needs a symbol alignment phase, so coherent integration periods can be aligned with symbol edges
Want to reuse existing work on SFDs that has been performed for base-mode preamble
Andy Ward, Ubisense
<author>, <company>

4. Signal acquisition phase
<month year>
doc.: IEEE <doc#>
May, 2010
Signal acquisition phase
A big long string of pulses at 2MHz
Provides fastest way of getting hold of signal using coherent receiver
No chance of being mistaken for valid data anyway (this is Manchester-encoded in long-range mode)
Suggest we make this at least 32x32 pulses, up to a maximum of 256x32 pulses at manufacturer’s discretion
Andy Ward, Ubisense
<author>, <company>

5. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
September 2009
What we had said before about long-range preamble and assisting base mode receivers…
Long Range Mode preamble must include the 1 pulse per symbol SFD as the last 16 pulses
Using 4 pulses per symbol for illustrative purposes only. Long Range mode actually uses 64 pulses per symbol:
Now 64 pulse periods, of which 32 are ‘on’ (Manchester encoding)
Base Mode
(1 MHz)
1:1 SFD
Long Range Mode
(2 MHz)
1111
1111
1111
1111
1111
1111
1111
1111
1111
1111
1111
1111
0001
0100
1001
1101
0000
0000
0000
1111
0000
1111
0000
0000
Etc.
1:1 SFD
4:1 SFD
SO, CONTINUE TO TRANSMIT 1:1 SFD AS LAST 16 BITS OF SIGNAL ACQUISITION PHASE (all 1s)
We will change these bits – see next slides!
Key:
Preamble
SFD
<author>, <company>

6. Symbol alignment phase and SFD
<month year>
doc.: IEEE <doc#>
May, 2010
Symbol alignment phase and SFD
Propose that we reuse base-mode SFD for long-range mode and prepend it with sixteen 1s
The SFD and 1s will be encoded with the standard long-range Manchester encoding
The SFD has already been shown to be robust at the end of a string of 1s (base-mode work)
The 1 symbols actually end up as a 64-pulse-period block of 32 pulses and 32 no-pulses, which is a lot of transitions on which to perform signal alignment
Andy Ward, Ubisense
<author>, <company>

7. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May, 2010
Summary
Proposed long-range preamble is:
Between 32x32 and 256x32 pulses at 2MHz; followed by
The 16-bit base-mode SFD encoded using 1:1 OOK at 2MHz; followed by
16 ‘1’ symbols encoded using standard long-range mode Manchester encoding; followed by
The base-mode SFD encoded using standard long-range mode Manchester encoding
Preamble
SFD
PHR
1024 to 8192 pulses
Base-mode SFD (16 2MHz periods)
22 bits
All Manchester-encoded as per normal long-range mode data
Andy Ward, Ubisense
<author>, <company>