1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Proposed Code Sequences for IEEE a Alt-PHY]
Date Submitted: [9 Nov, 2004]
Source: [Francois Chin, Sam Kwok, Xiaoming Peng, Kannan, Yong- Huat Chew, Chin-Choy Chai, Hongyi Fu, Manjeet, Tung-Chong Wong, T.T. Tjhung, Zhongding Lei, Rahim]
Company: [Institute for Infocomm Research, Singapore]
Address: [21 Heng Mui Keng Terrace, Singapore ]
Voice: [ ] FAX: [ ]
Re: [Response to the call for proposal of IEEE b, Doc Number: b]
Abstract: [This presentation compares all proposals for the IEEE b PHY standard.]
Purpose: [Proposal to IEEE b Task Group]
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
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

2. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Proposed Code Sequences
for IEEE a Alt-PHY
Francois Chin
Institute for Infocomm Research
Singapore
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

3. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Proposed System Parameters
Chip rate
16 Mcps
Pulse Rep. Freq.
16 MHz
Symbol Rate
0.5 MHz
Min. info. bit / sym.
4 bit / symbol
Max bit rate
4 x 0.5 = 2.0 Mbps
# Chip / symbol (Code length) 32
#Code Sequences/ piconet
16 (4 bit/symbol)
Code position modulation (CPM)
Lower bit rate
Pulse Repetition
Modulation
On-Off Keying (OOK)
Total # simultaneous piconets supported 6
Multple access for piconets
Fixed band and sequence for each piconet
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

4. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
UWB Pulse & Spectrum
1.5 ns rectified rectified cosine shape
~1400 MHz 10-dB bandwidth
Centre frequency 4 GHz
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

5. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Code Sequence Set
Seq 1
Seq 2
Seq 3
Seq 4
Seq 5
Seq 6
31-chip M-Sequence set
Only one sequence and one fixed band (no hopping) will be used by all devices in a piconet
Logical channels for support of multiple piconets
6 sequences = 6 logical channels (e.g. overlapping piconets)
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

6. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Gray Coded Code Position Modulation (CPM)
Symbol
Cyclic shift to right by n chips, n=
32-Chip value
0000
0001 2
0011 4
0010 6
0110 8
0111 10
0101 12
0100 14
1100 16
1101 18
1111 20
1110 22
1010 24
1011 26
1001 28
1000 30
To obtain 32-chip per symbol, cyclic shift first, then extend 1-chip
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

7. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Cyclic Extended Chip
To avoid / reduce inter-symbol interference in channels with excess delay spread
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

8. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Properties of M-Sequences
Cyclic auto-correlation of any antipodal sequence gives peak value of 31 and sidelobe value of -1 throughout
Cyclic correlation of any antipodal sequence with its corresponding uni-podal sequence give peak value of 16 and zero sidelobe throughout
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

9. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Synchronisation Preamble
Correlator output for synchronisation
Code sequence has excellent autocorrelation properties
Preamble is constructed by repeating base Code Sequence
Unique – no symbol & spreading combination can construct this preamble
Unlike 15.4, where preamble is constructed by 8x ‘0000’ symbols
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

10. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Comparison with other Sequences
Say 31-chip Gold Sequences as follows:
Seq 1
Seq 2
Seq 3
Seq 4
Seq 5
Seq 6
Grey coded CPM is also employed
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

11. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Comparison with other Sequences
Using square envelop detector, integrate – dump & soft despreading, M-Sequence has better multipath performance in Residential LOS & NLOS than Gold Sequences, by ~1.5dB
CM2 (NLOS) performance is slightly worst than CM1 (LOS)
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

12. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Comparison with other Sequences
M-Sequence has better single isolated piconet performance due to its excellent cross correlation between mapping sequences
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

13. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Inter-Piconet Interference Suppression
Let investigate the false alarm probability in the presence of one & two overlapping piconets with asynchronous operation, all piconets using sequences from either M-Sequence Code Set or Gold Sequence Code Set
Code Set for all piconets
False Alarm Probability
Interference suppression at corr output
(1 interfering piconet)
Interference suppression at corr. output
(2 interfering piconets)
M-Sequence
2.0x10-3%
15.0 dB
11.8 dB
Gold sequence
1.2x10-2%
14.5 dB
11.4 dB
M-Sequence Code Set gives lower false alarm probability and better suppression
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>

14. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Nov 2004
Summary
M-Sequence Codes is recommended for low rate low-power UWB:
Low cyclic auto-correlation
One sequence for the entire piconet for
Better synchronisation / acquisition performance due to low autocorrelation properties;
Simple and robust symbol-to-chip mapping using cyclic shifts;
One code set for simultaneous operating piconets with Good interference suppression capability among the piconets
Francois Chin, Institute for Infocomm Research (I2R)
<author>, <company>