1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Jan 2005
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [COBI-8 with Offset QPSK for b High Rate Alt-PHY for 868MHz band]
Date Submitted: [17 Jan, 2004]
Source: [Francois Chin, Lei Zhongding, Sam Kwok, Manjeet Singh] 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. Proposed Symbol-to-Chip Mapping (8-chip Code Set C8)
Jan 2005
Proposed Symbol-to-Chip Mapping (8-chip Code Set C8)
Decimal Value
Binary Symbol
Chip Value
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
The sequences are related to each other through cyclic shifts and/or conjugation (i.e., inversion of odd-indexed chip values)
Francois Chin, Institute for Infocomm Research (I2R)

3. Other Root Sequences (8-chip C8 for Coherent Despreading only)
Jan 2005
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:
Francois Chin, Institute for Infocomm Research (I2R)

4. Frequency Response– raised cosine filter r=0.2
Jan 2005
Source b-proposal-preamble-struture-ieee b-phy
Frequency Response– raised cosine filter r=0.2
SUPPOSE:
1, 1.6MHz (4x)sampling rate;
2, 250kHz pass band;
3, Tx digital FIR filter;
4, 8 taps;
Francois Chin, Institute for Infocomm Research (I2R)

5. Impulse response of Tx filter – raised cosine filter r=0.2
Jan 2005
Source b-proposal-preamble-struture-ieee b-phy
Impulse response of Tx filter – raised cosine filter r=0.2
SUPPOSE:
1, 1.6MHz (4x)sampling rate;
2, 250kHz pass band;
3, Tx digital FIR filter;
4, 8 taps;
Francois Chin, Institute for Infocomm Research (I2R)

6. PSD for Half-sine with Tx filter
Jan 2005
Source b-proposal-preamble-struture-ieee b-phy
PSD for Half-sine with Tx filter
100kbps;
400k chip rate;
600k bandwidth;
half sine pulse shape;
8 taps FIR Tx filter;
Raised cosine filter
with r=0.2;
4x over sampling rate;
(1.6M sampling rate)
Francois Chin, Institute for Infocomm Research (I2R)

7. Nonlinear PA Characteristics
Jan 2005
Source b-proposal-preamble-struture-ieee b-phy
Nonlinear PA Characteristics
Francois Chin, Institute for Infocomm Research (I2R)

8. Impact of PA Nonlinearity: 4x sampling rate
Jan 2005
Source b-proposal-preamble-struture-ieee b-phy
Impact of PA Nonlinearity: 4x sampling rate
(2)
(1)
(1) Tx PSD without Tx filter or PA
(2) Tx PSD with Tx filter, no PA
(3) Tx PSD with Tx filter and PA
At 4x sampling rate, the impact of PA nonlinearity is neglectable.
(3)
Francois Chin, Institute for Infocomm Research (I2R)

9. Simulation models –PER calculated on 20 bytes PPDUs with preamble;
Jan 2005
Simulation models
Discrete exponential channel model
–-Sampled version of diffuse channel model offer by Paul with 4x sampling rate;
–PER calculated on 20 bytes PPDUs with preamble;
Francois Chin, Institute for Infocomm Research (I2R)

10. Proposal for preamble Preamble of 15.4 standard:
Jan 2005
Proposal for preamble
Preamble of 15.4 standard:
Preamble proposed for COBI-8 consists of 8 octets
(each octet comprises the least significant symbol ‘0000’ and the most significant symbol ’0111’) and the chip sequence will be
[ ]
Francois Chin, Institute for Infocomm Research (I2R)

11. Auto-correlation of un-modulated COBI-8
Jan 2005
Auto-correlation of un-modulated COBI-8
Snapshot Of Normalized Correlation Values with 6 octet as example
Francois Chin, Institute for Infocomm Research (I2R)

12. Synchronisation Performance
Jan 2005
Synchronisation Performance
Simulation parameters & assumptions:
AWGN
O-QPSK + half-sine pulse shaping + Transmit filtering Raised cosine (r=0.2)
4x 1.6MHz (chip rate = 400kcps)
No Frequency offset
Francois Chin, Institute for Infocomm Research (I2R)

13. Synchronisation Performance
Jan 2005
Synchronisation Performance
Francois Chin, Institute for Infocomm Research (I2R)

14. System Performance Simulation parameters & assumptions:
Jan 2005
System Performance
Simulation parameters & assumptions:
Flat fading & 250ns rms delay spread Rayleigh Channel model
O-QPSK modulation + half sine pulse + Transmit filtering Raised cosine (r = 0.2)
20 octets in each packet
20,000 packets for Monte-Carlo simulation
No Sync error
Non-coherent demodulation
No SFD detection
Francois Chin, Institute for Infocomm Research (I2R)

15. AWGN Jan 2005 Enhanced COBI-8 differs from DSSS by ~ 2dB due to
quasi-orthogonal cross correlation among the sequences
Francois Chin, Institute for Infocomm Research (I2R)

16. AWGN: Ideal Sync. vs. Correlation Sync.
Jan 2005
Source: b-proposal-preamble-struture-ieee b-phy
AWGN: Ideal Sync. vs. Correlation Sync.
DSSS performance
from previous page
matches this
Packet Number: 10000
PSDU Length: 20 Byte
Tx/Rx Over Sample Rate: 2
Channel Over Sample Rate: 4
Frame Detection: No
SFD: No
Francois Chin, Institute for Infocomm Research (I2R)

17. Non-Coherent Receiver
Jan 2005
Non-Coherent Receiver
Francois Chin, Institute for Infocomm Research (I2R)

18. Jan 2005
Coherent Receiver
Francois Chin, Institute for Infocomm Research (I2R)