Transcript Dynamic Range Increase for Working with high PAPR

Dynamic Range Increase for Working with high PAPR
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number: IEEE S802.16m-08/159
Date Submitted: 2008-03-10
Source:
Zeev Cohen
Paragon
Doron Ezri
Michael Erlihson:
Runcom
E-mail: [email protected]
Email: [email protected]
Email: [email protected]
Venue:
Orlando, US.
This presentation follows the TGm call for contributions on Project 802.16m System Description Document (SDD) (802.16m-08/005),
specifically, on the issue of Downlink Physical Resource Allocation Unit.
Base Contribution:
none
Purpose:
To show that the PAPR problem coupled with OFDMA can be reduced or accommodated by various techniques and to conclude that
OFDMA is the preferred transmission technology for 802.16m.
Notice:
This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in
the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material
contained herein.
Release:
The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an
IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s
sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this
contribution may be made public by IEEE 802.16.
Patent Policy:
The contributor is familiar with the IEEE-SA Patent Policy and Procedures:
<http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>.
March 21, Further
2007, Presentation
to Verizon is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.
information
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1
The Problem: Transmitting Signals with High PAPR
• To ensure high linearity transmission of signals with high PAPR (Peak
to Average Power Ratio), Power Amplifiers should cope with the
problem of transmitting the peaks.
• The way RF Power Amplifiers are designed today is that for a given
VCC the maximum RF power that can be transmitted with high linearity
is aligned to the signal’s peaks (Dotted Red Line) and the average
power that is transmitted is then reduced (backed off) approximately by
the signal’s PAPR.
• Working with PA’s in high back-off means that the average power
transmitted is much lower than the peak power that the PA can transmit
and therefore the PA efficiency is reduced dramatically.
March 21, 2007, Presentation to Verizon
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All other product or service names are the property of their respective owners. © Motorola, Inc. 2006.
2
System solutions to overcome high PAPR
• Crest Factor Reduction
 Pros: Reduces signal’s PAPR by 2-3 dB
 Cons:
 Additional IP/Chip
 EVM performance degrades
 Mask performance degrades
• SLM – Selective Mapping
 Pros: Reduces signal’s PAPR by 2-3 dB
 Cons:
 System complexity.
 Side information transmission is required (reduces BW).
 Overall gain is not clear.
March 21, 2007, Presentation to Verizon
MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office.
All other product or service names are the property of their respective owners. © Motorola, Inc. 2006.
3
Increasing Power Amplifier’s Dynamic Range to overcome high PAPR
iD
m=-1/ZL
Pout
Pmax,E
A
Pmax
vg
VDD VDD+vE
vE
Dynamic Range Increase:
March 21, 2007, Presentation to Verizon
MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office.
All other product or service names are the property of their respective owners. © Motorola, Inc. 2006.
vD

Pin
Pmax, E
Pmax
 V  VE 

  DD
 VDD 
2
4
Increasing Power Amplifier’s Dynamic Range to overcome
high PAPR
By partial envelope tracking we can change the VCC to the PA and raise
It when the signal’s peaks occur (Green line: signal envelope) to enable
them to be transmitted linearly (Blue Line).
March 21, 2007, Presentation to Verizon
MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office.
All other product or service names are the property of their respective owners. © Motorola, Inc. 2006.
5
Dynamic Range Increase: Performance Enhancements
• Output Power Increase:
20*Log (Vmax/Vnom)
• Efficiency Improvement:
Vmax/Vnom
• Same Linearity (EVM, Spectral Mask)
March 21, 2007, Presentation to Verizon
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All other product or service names are the property of their respective owners. © Motorola, Inc. 2006.
6
Dynamic Range Increase: Performance Results
30.0%
4.00%
3.50%
25.0%
3.00%
20.0%
15.0%
EVM(%)
Eff.(%)
2.50%
No Dynamic Range
2.00%
2.3GHZ, EVM_w/XNN @3.4V
2.3GHZ, EVM_no/XNN @3.4V
10.0%
1.50%
2.345GHz, EVM_w/XNN @3.4V
2.345GHz,EVM_no/XNN @3.4V 1.00%
2.39GHz, EVM_w/XNN @3.4V
2.39GHz, EVM_no/XNN @3.4V
5.0%
2.3GHz Eff_w/XNN[%] @3.4V
0.50%
2.3GHz, Eff_no/XNN[%] @3.4V
2.345GHz,Eff_w/XNN[%] @3.4V
0.0%
18
19
20
21
22
23
24
Pout(dBm)
25
26
2.345GHz,Eff_no/XNN[%] @3.4V 0.00%
27 2.39GHz, 28
Eff_w/XNN[%]29
@3.4V
2.39GHz, Eff_no/XNN[%] @3.4V
With Dynamic Range
Most PA’s tested provide more than 3dB Pout enhancement
March 21, 2007, Presentation to Verizon
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All other product or service names are the property of their respective owners. © Motorola, Inc. 2006.
7
Dynamic Range Increase: Implementation Complexity
• Two Blocks are needed:
 Envelope detector
 HW (sensing the RF) or
 SW
 Voltage Booster
 HW by 3 transistors and control
 Capacitor of 1uF (for charge boosting)
• Full HW solution implemented in 0.18u cmos process in
less than 2[mm^2]
March 21, 2007, Presentation to Verizon
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All other product or service names are the property of their respective owners. © Motorola, Inc. 2006.
8
• Dynamic Range Increase: Benefits
• Cops with signals with high PAPR
• Increased Linearity
• Higher Efficiency
• Prolong battery life
• Reduce PA current consumption
• Reduce heat dissipation
Better Power Amplifier Utilization!
March 21, 2007, Presentation to Verizon
MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office.
All other product or service names are the property of their respective owners. © Motorola, Inc. 2006.
9
• Conclusions
• The high PAPR introduced by OFDMA transmission may be reduced or
accommodated by various techniques.
• One of the most promising techniques is Dynamic Range Increase,
which may be implemented with low complexity at the transmitter.
• This leads to the understanding that OFDMA is the preferred
transmission technology for the 802.16m UL, which drawbacks may be
mitigated fairly easily.
March 21, 2007, Presentation to Verizon
MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office.
All other product or service names are the property of their respective owners. © Motorola, Inc. 2006.
10