design of power efficient power amplifier for 4g user terminals presented by abubakar sadiq...
TRANSCRIPT
Design of Power Efficient Power Amplifier for 4G User Terminals
Presented
By
Abubakar Sadiq Hussaini, IEEE, IET, OSA, NSE
Raed A. A. Alhameed & Jonathan Rodriguez
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I suppose we need to ask where the power goes in mobile phones:
Some is unavoidably used in communicating with the human being, so power has to be put into:
The audio signal and the visual information on the screen.
I don't think that the audio power could be reduced any more, unless the output amplifiers could be made more efficient, but I would imagine that they are all ready pretty good.
The power put into the screen might be reduced by using the headset display, and that could be a very significant argument for change in the way phones are used.
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After that, we have power absorbed in the digital circuits, but the digital community is well on top of the issue of reducing that.
We have antenna and link budget issues: What determines the noise floor in the link? Is it the environment, or is it in the circuits? Using high gain antennas would reduce the transmitter power requirements
Then we have the power taken by the RF section: I would expect that the transmitter is far more of a problem than the receiver.
What kind of transmitter architecture do we use? Is it a basic linear system, and hence rather lossy
If you wanted to reduce the waste power in the transmitter, then you can learn lessons from the high-power broadcasting community who have used things like Doherty modulation and delta modulation
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Outline Motivation
Introduction
Power consumptions
Innovation
State of the art
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Outline Design
Operation
Results
Conclusion
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Motivation
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ICT power consumption
This is 3% of global power consumption 2% of global CO2 emissions Power consumption of ICT is increasing by 16-20% per year
Motivation
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Reconfigurable
Low-Cost
Power Efficient
Highly integrated
Introduction
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Multi-standard radios (GSM, UMTS,WCDMA, DVB-T, Mobile WiMAX)
Thisradioscantheavailablespectrumandchangeitsnetworkparameters(frequency, bandwith, modulation) for maximumdata transfer
Introduction
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Power amplifier consumes the highest power and convert more than 50% of the power into heat
Power consumptions
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An efficient architecture and maintaining the QoS
Radio implementation: Power amplifierAntennas and antenna interface DSP
Radio functionality: Energy efficient modulation and coding
Network coding and cooperative networks
Innovation
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Techniques such as Chireix outphasing, Doherty configuration, Kahn envelope elimination and Restorations(EER), And Envelope tracking (ET)
These will allow PAs to achieved good efficiency over a wide range of output power, yielding better overall efficiency
State of the art
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Design
Propose block diagram of Doherty RF power amplifier
Input signal
splitter
Class B
Class C
90 Degree
line
90 Degree Line
50 Ohms
Input Signal
OutputSignal
90 Degree offset Line
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4
1 4
1
PA 1
PA 2
Z
Z
Z
Operation
Block diagram of Doherty power amplifier
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Block diagram of Doherty power amplifier
4
1 4
1
PA 1
PA 2
Z
Z
ZX
Operation
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Prototype 1
Implemented prototype of proposed Doherty RF power amplifier
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Prototype 2
Power splitter
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Result 1
Insertion loss
-1 0 1 2 3 4 5 6 7 8
-3.6
-3.5
-3.4
-3.3
-3.2
-3.1
-3.0
Inse
rtio
n Lo
ss (dB
)
Freq (GHz)
S(3,1) S(2,1)
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Result 2
Phase difference
-1 0 1 2 3 4 5 6 7 8
-200
-150
-100
-50
0
50
100
150
200
Phase
(degre
e)
Freq (GHz)
S(3,1) S(2,1)
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Result 3
Gain Characteristics
14 16 18 20 22 24 26 28 30 324
6
8
10
12
14
16
Tra
nsdu
cer P
ower
Gai
n (d
B)
Output Power(dBm)
Class B Load Modulation
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Result 4
AM-AM Characteristics
0 5 10 15 20 25
10
15
20
25
30
35
AM
-AM
(dB
m)
Input Power (dBm)
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Result 5
AM-PM Characteristics
0 5 10 15 20 253.0
3.5
4.0
4.5
5.0
5.5
6.0
AM
-PM
(D
egre
e)
Input Power (dBm)
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Result 6
Power-Added Efficiency
10 15 20 25 30 35
0
10
20
30
40
50
60
PA
E (%
)
Output Power (dBm)
Load Modulation Class B
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Result - Comparison
Comparison performance of Class B and Load modulation at Pout 1dB compression point
Amplifier Gain (dB) Pout (dBm) at 1dB PAE (%) at P1dB
Class B amplifier 15.4dB 27.5dBm 37%
Load modulation 11.8dB 30dBm 53%
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The performance comparisons between Doherty RF power amplifier and conventional class B RF power amplifier are performed.
The achieved results of the proposed design process have shown an excellent efficiency and power performances.
Applying Doherty technique can significantly reduce the CO2 emission and power consumption in the transceiver.
The self-managing characteristic of the Doherty RF power amplifier has made its implementation more attractive.
Conclusion
