doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 1 Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Enhanced COBI-16 with Offset QPSK for b High Rate Alt-PHY] Date Submitted: [13 Mar, 2004] Source: [Francois Chin, Yuen-Sam Kwok, Lei Zhongding] 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

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 2 It is desirable choose a code sequences that will lead to efficient transmission and low implementation complexity. In particular, it should: 1.Avoid spikes in frequency spectrum 2.Simplify correlation operations 3.Enable simple frequency offset and DC compensation Motivation

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 3 As such, it is desirable that the code sequences have the following properties: 1.All sequences contain an equal number of ones and zeros in total 2.All sequences contain an equal number of ones and zeros in the even numbered chips (I phase) 3.All sequences contain an equal number of ones and zeros in the odd numbered chips (Q phase) 4.Total phase rotation in I / Q plane accumulates to 0 degree over the complete symbol 5.The first 8 symbols are shifted versions of each other 6.The last 8 symbols have inverted odd numbered chips (Q phase); when compared to the 8 first symbols, have the exact inverted baseband phase Motivation

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 4 The COBI-32 code sequences satisfy all the 6 requirements. Challenge: Can we find a shorter 16-chip code sequences that give better bandwidth and, at the same time, satisfy all the 6 requirements? Motivation

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 5 YES!!

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 6 The sequences are related to each other through cyclic shifts and/or conjugation (i.e., inversion of odd-indexed chip values) Proposed Symbol-to-Chip Mapping (Enhanced 16-chip COBI Code Set ω 16 ) Decimal ValueBinary SymbolChip Value (Root – 3E25)

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 7 COBI-16 Sequences ω 16 The proposed code set satisfy all 6 requirements!!! Another Root Sequence, with identical performance, is also found through exhaustive search: –[ ] (Root – A47C) Which is a direct left-right flip of previous root sequence IN FACT, other base sequence can be established by –Any combination of cyclic shifts, bit inversion & sequence flips of the base sequence (3E25 hex)

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 8 TX PSD (915 MHz), RBW = 16 kHz Meet ETSI Mask

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 9 TX PSD (915 MHz), RBW = 100 kHz Meet ETSI Mask

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 10 TX PSD (868 MHz) Roll-off = 0.2, RBW = 16 kHz Meet ETSI Mask

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 11 TX PSD (868 MHz) Roll-off = 0.2, RBW = 100 kHz Meet ETSI Mask

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 12 TX PSD (868 MHz) Roll-off = 0.2, RBW = 16 kHz Not Meet ETSI Mask

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 13 TX PSD (868 MHz) Roll-off = 0.6, RBW = 16 kHz Not Meet ETSI Mask

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 14 TX PSD (868 MHz) Roll-off = 0.6, RBW = 16 kHz Not Meet ETSI Mask

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 15 TX PSD (868 MHz) Roll-off = 0.2, 2x sampling To meet ESTI mask with 40ppm crystal, small roll-off factor 0.2 has to be employed The proposed tap weights are:

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 16 EVM

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 17 Preamble Structure Preamble structure is the same as of 15.4 standard:

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 18 Auto-correlation of un-modulated COBI-16 Snapshot Of Normalized Correlation Values with 6 octet as example

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 19 Cross-correlation of Enhanced COBI-16 There is a performance cost to pay for this quasi-orthogonality as compared to another orthogonal code, like DSSS Let’s quantify the loss…

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 20 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;

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 21 Simulation parameters & assumptions: –Flat fading & 250ns rms delay spread Rayleigh Channel model –O-QPSK modulation + half sine pulse + Transmit filtering Raised cosine (roll-off = 0.2) –20 octets in each packet –20,000 packets for Monte-Carlo simulation –Sync + SFD error taken into account –2x oversampling –Non-coherent demodulation System Performance

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide MHz AWGN (Non-coherent)

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide MHz AWGN (Non-coherent)

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 24 Non-Coherent Receiver (with Tx Filter r=0.2)

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 25 Synchronisation False Alarm (915 MHz Band)

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 26 Synchronisation Miss Detection (915 MHz Band)

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 27 Synchronisation False Alarm (868 MHz Band)

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 28 Synchronisation Miss Detection (868 MHz Band)

doc.: IEEE b Submission March 2005 Francois Chin, Institute for Infocomm Research (I 2 R) Slide 29 enhanced COBI-16 can satisfy the stated 6 criteria that will Avoid spikes in frequency spectrum Simplify correlation operations Enable simple frequency offset and DC compensation Summary