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5G Advanced Waveforms and RF
Presentation / Jan 2013 / 5G, MWC, Advanced Waveforms

MWC 2013 presentation for 5G Advanced Waveforms and RF that covers key advantages, use cases, digital pre-distortions, crest factor reduction, envelope tracking and more.

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MWC 2013
5G Advanced Waveforms and RF
© 2013 InterDigital, Inc. All rights reserved.
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Advanced Waveforms and RF
Spectral agility
Improving spectrum utilization of baseband waveforms (e.g. OFDM in 3GPP and WiFi standards) when the available channels are non-contiguous and shared with multiple systems
Energy efficiency
Raising efficiency of Multi-channel transmissions with joint RF-Baseband techniques
Key Advantages
Addressing the limitations of current Physical Layer techniques when used in emerging architectures (OFDM, MIMO, etc.)


InterDigital Waveform Evaluation Platform
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© 2013 InterDigital, Inc. All rights reserved.
Spectral Agility means we can provide dynamic channel access in a manner to support non-contiguous and flexible bandwidth channel access

Source of figures: DoComo, 3GPP R12 Workshop, Warsaw, June 2012

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Use Cases
Performance enhancement for Dynamic Spectrum Management (DSM) Networks
TVWS and unlicensed bands (e.g. 802.11af+)
Licensed Shared Access (LSA)
PCAST Recommendations
Cognitive Radio
3GPP multi-layer Heterogeneous networks

Solutions include new waveforms for increasing spectrum utilization with shared spectrum architectures
Waveforms must maintain or improve on energy efficiency




7km
TVWS
Macro interferes with small cell networks
Up to 80% cell edge throughput loss!
UE interferes with adjacent DTV
MACRO-SMALL CELL
Small Cell BS
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© 2013 InterDigital, Inc. All rights reserved.
 President's Council of Advisors on Science and Technology (PCAST) for increased sharing of radio spectrum.

The final PCAST report recommends that the President issue a memorandum stating that the U.S. government's policy is to share as much as 1,000 MHz of unutilized government-held spectrum with commercial broadband networks. The goal is to make better use of a huge swath of the radio spectrum now controlled by federal agencies.
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Advanced Waveforms
Bandwidth agile waveforms with lower adjacent channel interference enable flexible use of spectrum
FBMC (OFDM-OQAM): fine resolution spectral agility at the expense of latency and complexity
RB-OFDM: practical amount of complexity by using Resource Block (RB) level resolution



“Spectrum hole”
used by other users
Out of Band
In-Band
Out of Band
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© 2013 InterDigital, Inc. All rights reserved.
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Advanced RF: Digital Pre-Distortions (DPD)
DPD – Digital linearization of non-linear Power Amplifier
Closed loop DPD gains up to 20dB in ACLR
Required Baseband bandwidth – 5x



Complex to ABS-Angle
ABS-Angle to complex
Memory effect correction
ABS-Angle
correction
DPD block diagram
Before correction (no DPD)
Red – input
Blue – output
After correction (with DPD)
Red – input
Blue – output
Input
Output
M
A
M
A
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© 2013 InterDigital, Inc. All rights reserved.
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Advanced RF: Crest Factor Reduction (CFR)
CFR – Digital signal conditioner for maximizing Power Amplifier efficiency
CFR gains 2 to 3dB in max power with the same ACLR
Adaptive CFR reduce compression at low output power


Complex to ABS-Angle
ABS-Angle to complex
Clip
CFR block diagram
Input
Output
LPF

Magnitude before CFR – purple
Magnitude after CFR – green

Spectrum before CFR – red
Spectrum after CFR – blue
TPC
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© 2013 InterDigital, Inc. All rights reserved.
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Advanced RF: Envelope Tracking (ET)
ET – Power conditioner for maximizing Power Amplifier efficiency
ET gains 3 times at output power of -10dBFS
Adaptive ET could be disable below -20dBFS


ET block diagram
Envelope signal – yellow
PA Vcc – purple

Complex to magnitude
Input
Vcc
PA
Modulator
Low voltage power supply

Efficiency gain
RF Output
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© 2013 InterDigital, Inc. All rights reserved.
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Further enhancing DSM efficiencies
Fixed Channel Bandwidth
Multi-Channel Aggregation
Coexistence and Database Mechanisms
Sensing Toolbox


LTE
Wi-Fi
Other
Spectrally contained waveform
Non-contiguous and flexible bandwidth channels
Efficient integrated RF and Baseband design
InterDigital DSM Solution
InterDigital Advanced Waveform and RF
Baseband Modulation
RF/PA
Bandwidth Agile Dynamic Spectrum Management
Linearization
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© 2013 InterDigital, Inc. All rights reserved.
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