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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [ OQPSK Cross-Talk Characteristics ] Date Submitted: [ 12 March 2001 ] Source: [ Rick Roberts ] Company [ XtremeSpectrum ] Address [ 8133 Leesburg Pike, Vienna, Va. 22182 ] - PowerPoint PPT Presentation
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12 March 2001
<author>, <company>Slide 1
doc.: IEEE 802.15-<01113>
Submission
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [OQPSK Cross-Talk Characteristics]Date Submitted: [12 March 2001]Source: [Rick Roberts] Company [XtremeSpectrum]Address [8133 Leesburg Pike, Vienna, Va. 22182]Voice:[703.749.0230], FAX: [703.749.0249], E-Mail:[[email protected]]
Re: [ revision zero]
Abstract: [Discussions the cross talk nature of OQPSK]
Purpose: [Support TG PHY Committee]
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.
12 March 2001
<author>, <company>Slide 2
doc.: IEEE 802.15-<01113>
Submission
Simplistic Example of Cross-Correlation Problem in OQPSK
Consider OQPSK transmission in a simple complex impulse response channel
I
Q
I1
I2 I3
I4
I5
Q1
Q2 Q3
Q4 Q5
Notice the Cross Talk Between the I and Q Channels and the Locate of the Zero Crossing
QI1
QI2 QI3
QI4 QI5
IQ1
IQ2 IQ3
IQ4
IQ5
Now cross correlate between the two channels “at the respective sample time for each arm”
Xqi = E[Q1*QI1 + Q2*QI2 + Q3*QI3 + Q4*QI4 + Q5*QI5]
Xiq = E[I1*IQ1 + I2*IQ2 + I3*IQ3 + I4*IQ4 + I5*IQ5]
12 March 2001
<author>, <company>Slide 3
doc.: IEEE 802.15-<01113>
Submission
Now time align the I and Q channels as an OQPSK receiver would do using a time delay
I
Q
I1
I2 I3
I4
I5
Q1
Q2 Q3
Q4 Q5
Notice the Cross Talk Between the I and Q Channels and the Locate of the Zero Crossing
QI1
QI2 QI3
QI4 QI5
IQ1
IQ2 IQ3
IQ4
IQ5
Now cross correlate between the two channels “at the sample time”
Xqi = E[Q1*I1 + Q2*I2 + Q3*I3 + Q4*I4 + Q5*I5]
Xiq = E[I1*Q1 + I2*Q2 + I3*Q3 + I4*Q4 + I5*Q5]
Notice that the cross correlation value has changed! Statistically this is not the same signal! It is this change in statistics that I believe is causing problems for Jayhen. - Rick
