Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 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 138632] Voice: [65-6408-2530] FAX: [] E-Mail: [chinfrancois@i2r.a-star.edu.sg, kwokys@i2r.a-star.edu.sg zhangliang@vinnotech.com] Re: [Response to the call for proposal of IEEE 802.15.4G] Abstract: [This presentation compares all proposals for the IEEE802.15.4G standard.] Purpose: [Proposal to IEEE 802.15.4G 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. I2R, Vinno

2. 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. Current C(8,4) in Std draft I2R, Vinno

4. 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

5. 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

6. Proposed New Symbol-to-Chip Mapping (8-chip Code Set C8) The sequences are related to each other through cyclic shifts and odd-bit inversion. The first 8 and last symbols are both shifted versions of each other . I2R, Vinno

7. Search Based: Other Root Sequences (8-chip C8for Coherent Despreading only) • The following Root Sequences are found through exhaustive search with identical low cross correlation and autocorrelation, in base 10: 9 18 23 29 33 36 46 58 66 71 72 92 111 113 116 123 132 139 142 144 163 183 184 189 197 209 219 222 226 232 237 246 I2R, Vinno

8. 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

9. 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

10. Comparison cross-correlation of one Current C(8,4) code cross-correlation of one Proposed C8 code Several Peaks of the cross-correlation of the Current C(8,4) will introduce more demodulation error with coherent or non-coherent receiver. Hence, the Proposed C8 with only one Peak of the cross-correlation has better demodulation performance. I2R, Vinno

11. Cross-correlation Characteristics • The cross-correlation of current C(8, 4) (slide 4) indicates that decoding of the correct symbol based on maximum magnitude of correlation value is not possible I2R, Vinno

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

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

14. The Benefits of Proposed C8 code • The Correlation Calculation is still the basic processing for Decoding. • The stronger auto-correlation and improved cross correlation may decrease the PER • The Proposed code sequences are a round-shift of two essential codes. I2R, Vinno

15. 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

16. The Definition for Coherent and Non-Coherent Receivers • Coherent receiver • phase of received signal is synchronized • symbol detection based on maximum correlation value • Non-coherent receiver • phase of received signal is not synchronized • symbol detection based on magnitude of correlation value I2R, Vinno

17. Performance Comparison (BER) I2R, Vinno

18. Performance Comparison (PER) I2R, Vinno

19. Summary and Suggestion • New proposed COBI-Cs has the better cross-correlation Characteristics • The Proposed code sequences are a round-shift of two essential codes. • For low-complexity non-coherent receiver, New proposed COBI-C8 performance is much better. Suggestion: Adopt New Cobi-C8 chip sequence and instead of the current C(8,4) sequence in draft. I2R, Vinno