1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2010
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [New C(8,4) chip sequence for Multi-rate OQPSK Modulation]
Date Submitted: [12, May, 2010]
Source: [Francois Chin, Yuen-Sam Kwok, Liang Zhang, Liang Li, Tao Xin, Haitao Liu] Company: [Institute for Infocomm Research, Singapore, Vinno, Huawei, SIMIT]
Address: [1 Fusionopolis Way #21-01 Connexis South Tower, Singapore ]
Voice: [ ] FAX: []
Re: [Response to the call for proposal of IEEE G]
Abstract: [This presentation compares all proposals for the IEEE G standard.]
Purpose: [Proposal to IEEE G 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
I2R, Vinno
<author>, <company>

2. May 2010
Motivation
Current (8,4)-DSSS code sequence for high rate mode does not support non-coherent receiver.
It is desirable choose a code sequences that supports low-complexity non-coherent receiver.
I2R, Vinno

3. Six desirable properties of DSSS code sequences
May 2010
Six desirable properties of DSSS code sequences
All sequences contain equal number of ones and zeros
All sequences contain equal number of ones and zeros in the even numbered chips (I phase)
All sequences contain equal number of ones and zeros in the odd numbered chips (Q phase)
Total phase rotation in I / Q plane accumulates to 0 degree over a complete symbol period
The first 8 symbols are shifted versions of each other
The last 8 symbols have inverted odd numbered chips (Q phase); when compared to the 8 first symbols, have the exact inverted baseband phase
I2R, Vinno

4. Proposed New Symbol-to-Chip Mapping (8-chip Code Set C8)
May 2010
Proposed New Symbol-to-Chip Mapping (8-chip Code Set C8)
Decimal Value
Binary Symbol
Chip Value
DC Offset
0000
(Root – 5C) 1
1000 2
0100 3
1100 4
0010 5
1010 6
0110 7
1110 8
0001 9
1001 10
0101 11
1101 12
0011 13
1011 14
0111 15
1111
I2R, Vinno

5. No DC offset of EACH Symbol!!!
May 2010
The sequences are related to each other through cyclic shifts and odd-bit inversion.
No DC offset of EACH Symbol!!!
I2R, Vinno

6. Other Root Sequences (8-chip C8 for Coherent Despreading only)
May 2010
Other Root Sequences (8-chip C8 for Coherent Despreading only)
The following Root Sequences are found through exhaustive search with identical low cross correlation and autocorrelation, in base 10:
I2R, Vinno

7. Cross-correlation Characteristics for Proposed C8
May 2010
Cross-correlation Characteristics for Proposed C8
(a) cross-correlations of all 16 COBI-C8 codes
(b) cross-correlation of one COBI-C8 code
No modulation; no over-sampling (all in real numbers)
I2R, Vinno

8. Cross-correlation Characteristics for Proposed C8
May 2010
Cross-correlation Characteristics for Proposed C8
(a) cross-correlations of all 16 COBI-C8 codes
(b) cross-correlation of one COBI-C8 code
With O-QPSK modulation; 2x over-sampling (complex domain)
I2R, Vinno

9. Autocorrelation Characteristics of C8
May 2010
Autocorrelation Characteristics of C8
Autocorrelation of all 16 COBI-C8 sequences
No modulation; no over-sampling (all in real numbers)
I2R, Vinno

10. Autocorrelation Characteristics of C8
May 2010
Autocorrelation Characteristics of C8
Autocorrelation of all 16 COBI-C8 sequences
O-QPSK modulation; 2x over-sampling (complex domain)
I2R, Vinno

11. Current C(8,4) in Std draft
May 2010
Current C(8,4) in Std draft
Decimal Value
Binary Symbol
Chip Value
DC Offset
0000
4 + 2*i 1
1000
2 + 0*i 2
0100
0 + 2*i 3
1100
-2 + 0*i 4
0010
0 - 2*i 5
1010 6
0110 7
1110
2 – 4*i 8
0001
-2 + 4*i 9
1001
0 – 2*i 10
0101 11
1101 12
0011 13
1011 14
0111 15
1111 *i
I2R, Vinno

12. Cross-correlation Characteristics for Current C(8,4) in Std draft
May 2010
Cross-correlation Characteristics for Current C(8,4) in Std draft
(a) cross-correlations of all 16 COBI-C8 codes
(b) cross-correlation of one COBI-C8 code
No modulation; no over-sampling (all in real numbers)
I2R, Vinno

13. Cross-correlation Characteristics for Current C (8,4) in Std draft
May 2010
Cross-correlation Characteristics for Current C (8,4) in Std draft
(a) cross-correlations of all 16 COBI-C8 codes
(b) cross-correlation of one COBI-C8 code
With O-QPSK modulation; 2x over-sampling (complex domain)
I2R, Vinno

14. System Performance Simulation parameters & assumptions:
May 2010
System Performance
Simulation parameters & assumptions:
O-QPSK + Raised cosine pulse shape with roll-off factor = 0.8
20 octets in each packet
20,000 packets for Monte-Carlo simulation
No Sync error
No SFD detection
Both Coherent and Non-coherent demodulation
I2R, Vinno

15. Performance Comparison (BER)
<month year>
doc.: IEEE <doc#>
May 2010
Performance Comparison (BER)
I2R, Vinno
<author>, <company>

16. Performance Comparison (PER)
<month year>
doc.: IEEE <doc#>
May 2010
Performance Comparison (PER)
I2R, Vinno
<author>, <company>

17. Summary and Suggestion
May 2010
Summary and Suggestion
New Proposed Cobi-C8 is Zero DC offset on each symbol
New proposed COBI-C8 can support low-complexity non-coherent receiver
Suggestion: Adopt New Cobi-C8 chip sequence and instead of the current C(8,4) sequence in draft.
I2R, Vinno