Design and Performance of LTE Enabled Base Station Antennas Derek Campbell Altair Engineering, Inc. Hampton, VA 23666 Antenna Systems Las Vegas November 6 – 7, 2014
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Design and Performance of LTE Enabled Base Station
Antennas
Derek CampbellAltair Engineering, Inc.
Hampton, VA 23666
Antenna SystemsLas Vegas November 6 – 7, 2014
• Motivation
• Design Challenges
• Design Tools
• Base Station Antenna
• 3-Sector Antenna
• Conclusion
Overview
Motivation• LTE Experiencing Increased Popularity
– Tablet PC Comprises 50% of PC Market
– LTE Smartphone Market Increased 91% in 2014
• LTE Coverage Increasing
Commercial LTE ServiceCommercial LTE Network PlannedTrial LTE Service
http://en.wikipedia.org/wiki/LTE_%28telecommunication%29#mediaviewer/File:3GPP_Long_Term_Evolution_Country_Map.svg
Motivation
• Wireless Communication Divided into Cells
– Base Station Communicates with Mobile Units
– Finite Communication Links over Finite Distance
• Cells Sub-Divided into Sectors
– Typically 3 or 6 Sectors/Cell
– Mitigates Self-Interference
Motivation• Performance Limited by Self-Interference
– Typical Cell Radius: 1 – 5 kilometers– Typical Base Station Height: 30 meters– Distance to Horizon Larger than Inter-Site Distance
𝑫𝑫 = 𝟐𝟐 � 𝑹𝑹 � 𝒉𝒉 + 𝒉𝒉𝟐𝟐
Variable Value(s) Description
R 6,371 km Earth Radius
h 0 – 45 m Height
• Motivation
• Design Challenges
• Design Tools
• Base Station Antenna
• 3-Sector Antenna
• Conclusion
Overview
Design Challenges• Wireless Lagging Wired Technology
– Offers 1/10th Performance at a Given Time– 10 – 15 Years Behind a Given Performance Level
• Difficult to Simultaneously Achieve– Maximum Coverage, Capacity and Reliability– Minimize Cost and Consumed Power
• Antenna Design is an Economical Solution– Efficiently Transmits Energy– Directs Energy Toward Terrestrial Users
Ghosh, Arunabha, et al. Fundamentals of LTE. Pearson Education, 2010.
Frequency• Frequency Band Features
– Low Frequencies Offer Increased Coverage– High Frequencies Offer Increased Bandwidth
• Regional Frequency Allocations– North America: 700, 800, 1900 and 2100 MHz– Europe: 800, 900, 1800 and 2600 MHz– Asia: 1800 and 2600 MHz
• Frequency Selection– 1800 MHz Widely Used Throughout Europe and Asia– Offers Both Coverage and Bandwidth
Ghosh, Arunabha, et al. Fundamentals of LTE. Pearson Education, 2010.
Polarization• Vertical Polarization
– Primarily Used for Earth-to-Earth Communication• Widely Distributed Mobile Units
– Optimal for Omni-Directional Radiation– Optimal for Both Urban and Rural Environments
• Horizontal Polarization– Primarily Used for Broadcast Television– Minimizes Interference with Man Made Noise (V-Pol)
• Circular Polarization– Primarily Used for Satellite Communication– Counteracts Faraday Rotation in Ionosphere
Beamwidth• Maximize Capacity and Coverage
– Common Azimuth Beamwidths: 90º, 65º, and 33º• 75% of Wireless Communication
– Common Elevation Beamwidths: 13º, 10º, and 7º• Larger Beamwidths are More Robust
10º Ver. HPBW500 m Inter-Site Distance
70º Ver. HPBW1732 m Inter-Site Distance
Yilmaz, O., S. Hamalainen, and J. Hamalainen. "Analysis of antenna parameter optimization space for 3GPP LTE." Vehicular Technology Conference Fall (VTC
2009-Fall), 2009 IEEE 70th. IEEE, 2009.
• Motivation
• Design Challenges
• Design Tools
• Base Station Antenna
• 3-Sector Antenna
• Conclusion
Overview
FDTD
Numerical Methods
Full-waveMethods(Rigorous Solution)
UTD
ELEC
TRIC
AL
SIZ
E
COMPLEXITY OF MATERIALS
Asymptotic Methods(High-Frequency Approximation)
Hybridization to Solve Large and
Complex Problems
PO/GO
MLFMM
MOM
FEM
• Searchable Antenna Database– 255 Total Antennas
Antenna Magus
EM Analysis
Modify Geometry
Op
timizationFinal Geometry
ParametersFrequencyGainVSWR
Antenna Magus
• Motivation
• Design Challenges
• Design Tools
• Base Station Antenna
• 3-Sector Antenna
• Conclusion
Overview
Antenna Element• Bi-Quad Antenna Element
– Offers Primary Specifications• Design Using Antenna Magus
– Optimize Using FEKO
Specification ValueSize/Shape CompactPolarization VerticalFrequency 1800 MHzWire Diameter 1 mmInput Impedance 50ΩAzimuth Beamwidth 65º
MoM
Elevation
Azimuth
Base Station Antenna• Design Using Antenna Magus
– Optimize Using FEKO
Specification ValueNumber of Elements 10Stack Direction VerticalElevation Beamwidth 10ºFront/Back Ratio 20 dB
MLFMM
Antenna Down Tilt• Mechanical Down Tilt
– Physically Rotate Antenna– Experiences ‘Pattern Blooming’
• Electrical Down Tilt– Adjust Excitation with Phase Shifters– Prevents Pattern Blooming– Recommend for Interference Limited Systems– Remote (RET), Variable (VET) and Fixed Methods
• RET Facilitates Real-Time Adjustment (e.g. Rush Hour)
– Increases Capacity ~50%
Mechanical Down Tilt• Can Tilt ~40% of Elevation Beamwidth
Azimuth Elevation
Electrical Down Tilt• Does NOT Experience Pattern Blooming
θs
∆𝝋𝝋 =𝑵𝑵 � 𝟑𝟑𝟑𝟑𝟑𝟑 � 𝒅𝒅 � 𝒔𝒔𝒔𝒔𝒔𝒔𝜽𝜽𝒔𝒔
𝝀𝝀
𝒅𝒅 =𝝀𝝀𝟐𝟐
Azimuth Elevation
Base Station Antenna• Design Using Antenna Magus
– Optimize Using FEKO
Specification ValueNumber of Elements 10Stack Direction VerticalDown Tilt Method ElectricalDown Tilt Position 12ºElevation Beamwidth 10ºFront/Back Ratio 20 dB
MLFMM
• Motivation
• Design Challenges
• Design Tools
• Base Station Antenna
• 3-Sector Antenna
• Conclusion
Overview
Results• Base Station Antennas In Free Space
Intel Xeon E5-2650 2.0GHz 8-core 20MB cache2 CPUs (16 cores) 256 GB RAM
Method Unknowns Run Time MemoryMoM 25,491 8.226 min 10.315 GBDGFM 36,900 4.360 min 0.574 GB
Results• Base Station Antennas In Situ
Intel Xeon E5-2650 2.0GHz 8-core 20MB cache2 CPUs (16 cores) 256 GB RAM
Method Unknowns Run Time MemoryMoM 42,108 25.05 min 27.619 GBMoM/PO 16,617 0.049 min 0.339 GB
• Motivation
• Design Challenges
• Design Tools
• Base Station Antenna
• 3-Sector Antenna
• Conclusion
Overview
Future• LTE Supports SU-MIMO
– LTE Release 10
– Beamforming• Supports 1 User Equipment (UE)
• Benefits from Decorrelated Signals
• LTE Advanced Supports MU-MIMO– LTE Release 11
– Beamforming• Supports 8 User Equipment (UE)
• Benefits from Correlated Signals
>4λ
<1λ
Conclusions• LTE Popular Standard
– Wireless Communication
• Base Stations Relay Communication– Link Between User Equipment
• Several Technical Challenges– Achieve Higher SINR for Lower Cost
• CEM Analysis is a Critical Solution– FEKO: Leader for Electrically Large Base Stations
• Exciting New Technology in Development– LTE Advanced
Related Documents
