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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Proposed Code Sequences for IEEE 802.15.4a Alt-PHY ] Date Submitted: [13 Sept, 2004] - PowerPoint PPT Presentation
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Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 1
doc.: IEEE 802.15-04-0525-01-004b
Submission
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)(WPANs)
Submission Title: [Proposed Code Sequences for IEEE 802.15.4a Alt-PHY]
Date Submitted: [13 Sept, 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 119613]
Voice: [65-68745684] FAX: [65-67768109] E-Mail: [[email protected]]
Re: [Response to the call for proposal of IEEE 802.15.4b, Doc Number: 15-04-0239-00-004b]
Abstract: [This presentation compares all proposals for the IEEE802.15.4b PHY standard.]
Purpose: [Proposal to IEEE 802.15.4b Task Group]
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(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 P802.15.
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 2
doc.: IEEE 802.15-04-0525-01-004b
Submission
Proposed Code Sequences for IEEE 802.15.4a Alt-PHY
Francois Chin
Institute for Infocomm ResearchSingapore
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 3
doc.: IEEE 802.15-04-0525-01-004b
Submission
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 250 kbps (2-layer CPM)
31.25 kbps (3-layer CPM)
3.90625 kbps (4-layer CPM)
Modulation BPSK or On-Off Keying (OOK)
Total # simultaneous piconets supported
6
Multple access for piconets Fixed band and sequence for each piconet
Proposed System Parameters
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 4
doc.: IEEE 802.15-04-0525-01-004b
Submission
Code Sequence Set
Seq 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1
Seq 2 1 0 1 1 1 0 0 0 1 0 1 0 1 1 0 1 0 0 0 0 1 1 0 0 1 0 0 1 1 1 1
Seq 3 1 1 0 1 1 1 1 1 0 1 0 0 0 1 0 0 1 0 1 0 1 1 0 0 0 0 1 1 1 0 0
Seq 4 0 1 0 1 1 1 0 1 1 0 0 0 1 1 1 1 1 0 0 1 1 0 1 0 0 1 0 0 0 0 1
Seq 5 1 1 1 1 0 0 1 0 0 1 1 0 0 0 0 1 0 1 1 0 1 0 1 0 0 0 1 1 1 0 1
Seq 6 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 1 1 0 1 1
• 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)
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 5
doc.: IEEE 802.15-04-0525-01-004b
Submission
Gray Coded Code Position Modulation (CPM)Symbol Cyclic shift
to right by n chips, n=
32-Chip value
0000 0 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1
0001 2 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 0
0011 4 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0
0010 6 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1
0110 8 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1
0111 10 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0
0101 12 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0
0100 14 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0
1100 16 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1
1101 18 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1
1111 20 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1
1110 22 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1
1010 24 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1
1011 26 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0
1001 28 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0
1000 30 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0
To obtain 32-chip per symbol, cyclic shift first, then extend 1-chip
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 6
doc.: IEEE 802.15-04-0525-01-004b
Submission
Cyclic Extended Chip
• To avoid / reduce inter-symbol interference in channels with excess delay spread
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 7
doc.: IEEE 802.15-04-0525-01-004b
Submission
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
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 8
doc.: IEEE 802.15-04-0525-01-004b
Submission
Inter-Piconet Interference Suppression• With one overlapping piconet with asynchronous operation, the
average interference suppression capability is 13.7dB
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 9
doc.: IEEE 802.15-04-0525-01-004b
Submission
N-layer CPM • To increase spreading gain to achieve reduce bit rate operation & coding
gain• Operation - The output of the symbol-to-chip mapper is fed into the same
symbol-to-chip mapper for N times• With N = 2, 4 bits is mapper to 32/4*32 = 256 chips• With N = 3, 4 bits is mapper to 32/4*32 /4 * 32 = 2048 chips
0001
1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 0
1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0
1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 0 0 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0
….
…. 16 Mcps
2 Mcps
250 kcps
31.25 kbps
….
….
Example of 3-layer CPM (for 31.25 kbps)
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 10
doc.: IEEE 802.15-04-0525-01-004b
Submission
Coding Gain of multiple-layer CPMAWGN performance @ BER=10-5
• 1-layer over PBSK: ~2.5 dB• 2-layer over 1-layer: ~ 5 dB• 3-layer over 2-layer: ~ 3.5 dB
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 11
doc.: IEEE 802.15-04-0525-01-004b
Submission
Synchronisation Preamble
• 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
Correlator output for synchronisation
Sept 2004
Francois Chin, Institute for Infocomm Research (I2R)Slide 12
doc.: IEEE 802.15-04-0525-01-004b
Submission
Summary
Advantages of M-Sequence Codes
• Low auto-correlation• One sequence for the entire piconet for
•Better synchronisation / acquisition performance due to low autocorrelation properties;•Simple symbol-to-chip mapping;•Further symbol spreading through self-generation layered mechanism to achieve considerable coding gains, leading to better coverage at reduced bit rate operations•Reasonably good suppression capability for simultaneous operating piconets
