Base Station Antenna Evolution and · PDF fileBase Station Antenna Evolution and Revolution...

September 18-19, 2012

Mobile Antenna Systems 2012 Denver, CO Base Station Antenna Evolution and Revolution David Barker, CTO Keith Radousky, CTO – Americas

Copyright © 2012 Quintel. All rights reserved. Quintel Confidential.

Dave Barker authored the submitted paper and this material. He was scheduled to present it today but

unfortunately he is unable to attend, so I will be presenting on his behalf.


The Capacity Crunch

• The Capacity crunch • We are all aware of it • By 2025 there may be 50x, 500x increase?

• How is it solved?

– More Spectrum (~3x increase by 2025) – More Spectral Efficient access tech (~3x increase by

2025) – More Spectral re-use/denser topologies (~?x increase) – Pricing mechanisms

• Small Cells are the acknowledged answer in the

form of Femtos, Picos, etc and part of a HetNet.

• But the Macro Layer won’t be replaced by Femto Layer, so how can the Macro layer evolve and be prepared for the Capacity crunch?

Source: Verizon

How do we close the gap?

Shannon’s Limit has essentially been

reached; this is all Spatial

Multiplexing/MIMO


Space Efficiency Techniques

Multi-array

Multi-Port

Combiners

How the Base Station Antenna has evolved Maxwell’s Laws not Moore’s Law

Source: 3G Americas; 3G & 4G Antenna Deployment

Point of Flux: Reconfigurable?

Active? Adaptive?

More Bands?

2012?

Spectral Efficiency Techniques

Spectral and Space

Efficiency Mutually Exclusive


Spectrum Evolution

400

500

600

700

800

900

1000

1400

1600

1700

1800

1900

2000

2100

2200

2300

2400

2500

2600

2700

1990 GSM/GPRS/EDGE

1998

2004

UMTS/HSPA/HSPA+

2020 White Space/Interleaved Spectrum 8x8 MIMO, CoMP, ICIC.

Elevation Beamforming Azimuth Beamforming

2012

LTE FDD Rel 8/9/10/11

2x2 MIMO and Tx Div.

• FCC, UK, India promise another 500MHz by 2020; and with “hands-off” approaches, incentive auctions and trading of spectrum.

• LTE-A is aligned with this multi-band concept to achieve 1Gbps and beyond. • Results in more Spectrum Neighbours = more Inter-System interference scenarios

(GPS, DTV, Public Safety, PMR/SMR) • Results in more Intra-System PIM Issues, especially with higher power Tx • Logic could be to eventually migrate to cognitive radio systems, as per White

Space model?

Receive Div. Only

2016 TD-LTE Rel 8/9/10/11

4x4 MIMO, CoMP. Azimuth Beamforming

DD2


More Spectrum Example of Intra System Interference

“Back to the Future” Solution

Problem

GSM/UMTS 850AB

LTE 700

Quintel MultiServ Antenna

(Tx)

Quintel MultiServ Antenna (Rx)

T R T R

700/850 Combiners

700/850 Combiners

700/850 Combiners

700/850 Combiners

700/850 Combiners

700/850 Combiners

700/850 Combiners

700/850 Combiners

Rx: 700BC

Tx: 700DEBC

Either Un-duplex or break out at native

Tx, Rx ports

All Tx Sub-Bands are Transmitted (30MHz)

A Spectral Efficiency Technique


MIMO Spectral Efficiency Evolution in LTE

ULA

numberofsources

averagerelativegain

CS/CB SU-MIMO 2x2 vs. SU-MIMO 2x2 9 cells 2 Cell avg 4.03%Cell-edge 4.42%

CS/CB SU-MIMO 4x2 vs. SU-MIMO 4x2 9 cells 4 Cell avg 5.32%Cell-edge 20.64%

CS/CB MU-MIMO 2x2 vs. MU-MIMO 2x2 9 cells 2 Cell avg 4.07%Cell-edge 8.93%

> 9 cells 1 Cell avg 5.66%Cell-edge 25.08%



JT SU-MIMO 2x2 vs. SU-MIMO 2x2 9 cells 3 Cell avg 1.55%Cell-edge 19.84%


JT MU-MIMO 2x2 vs. MU-MIMO 2x2 9 cells 3 Cell avg 13.53%Cell-edge 40.50%

JT MU-MIMO 4x2 vs. MU-MIMO 4x2 9 cells 5 Cell avg 11.40%Cell-edge 28.87%

> 9 cells 1 Cell avg -9.15%

Cell-edge 34.34%

cross-polarized antenna

numberofsources

averagerelativegain

CS/CB SU-MIMO 2x2 vs. SU-MIMO 2x2 1 Cell avg 1.46%Cell-edge 2.86%

CS/CB SU-MIMO 4x2 vs. SU-MIMO 4x2 5 Cell avg 5.65%Cell-edge 16.68%






JT SU-MIMO 4x2 vs. SU-MIMO 4x2 9 cells 5 Cell avg 3.57%

Cell-edge 21.78%JT MU-MIMO 2x2 vs. MU-MIMO 2x2 9 cells 7 Cell avg 4.07%

Cell-edge 40.72%> 9 cells 1 Cell avg 3.57%

Cell-edge 18.57%JT MU-MIMO 4x2 vs. MU-MIMO 4x2 9 cells 7 Cell avg 8.70%

Cell-edge 31.35%> 9 cells 1 Cell avg 6.86%

JT: Joint Transmission (Multi-Cell Tx) CS/CB: Co-ordinated Scheduling & Beamforming

2x2 Single User MIMO

R8

2012

3GPP Study item in release 11 LTE 3GPP TR 36.819 V11.0.0 (2011-09) captures these simulation results. CoMP/ICIC techniques in particular improve cell edge performances. Slow but steady evolution in Spectral Efficiencies, at the expense of complexity.

2x2 Multi User MIMO

R9 Dual Layer Beamforming (R9) Azimuth Plane Coherent Beamforming

Emphasis on UE only having 2x

Antennas

4x2 Single User/Multi Cell MIMO (CoMP)

R10

2015 Tx1

Higher-order Azimuth Plane Coherent Beamforming

Tx2

4x2 Multi User/Multi Cell MIMO (CoMP)

R11

2018 Tx1

Tx2

1.4

1.8 2.3

2.5 2.7 3.5

3.0 3.4 4.0

Spectral Efficiency (bps/Hz)


MIMO Spectral Efficiency Evolution in LTE Dual Layer Beamforming in LTE Release 9

• With 3GPP Release 9 (TD-LTE) and Release 10 (FDD), a feature called “Dual Layer Beamforming” allows the LTE Downlink shared traffic channel to use 2x2 Spatial Multiplexing MIMO plus Adaptive Beamforming.

• With 4xPA’s (i.e. a 4T4R Base Station) you can transmit a signal on two feeders; each signal carrying the same information but having different phase weights.

• Example shown left, where different LTE Physical resource Blocks (i.e. different groups of LTE OFDM Sub-Tones) are delivered with different Azimuthally Beamformed patterns.

• Each user receives their respective signals via individual optimal Beamformed patterns.

• Beamforming in this way improves overall C/I which in turns ensures that Spatial Multiplexing occurs more often.

+45 -45

4T4R Base Station

+45 -45

Base Pattern of each array

Azimuthal Beamformed Patterns created for different users

(using different Physical Resource Blocks in Time & Frequency)


MIMO Engineering & Innovation Back to the Future: Space Diversity for Spectral Efficiency?

Quintel Dualband 8 Port Antennas (698-894MHz/1710-2170MHz)

6x Independent Tilts

LTE-AWS

UMTS 850

GSM 1900

GSM 850

LTE 700

UMTS 1900

700/850/1900 Combiners








Hybrid Space+Polz Diversity For all services

2x2 MIMO LTE(AWS) Remote Head Solution shown

• For 2x Antennas per sector. • Quintel solution allows initial 2x2 MIMO with

either: – Conventional X-Polar only, or – Spatially Separated orthogonal Polarisations

• Upgrade to 4x4 MIMO on 700 and AWS bands • Patented technique and application.

A Spectral Efficiency Technique

2x2 MIMO LTE700

“Back to the Future” Solution



Modelling and capacity of polarized MIMO channels Mikael Coldrey Ericsson Research, Ericsson AB, SWEDEN 1dB Spectral Efficiency Gains

1998 IEEE Paper 1dB Diversity Gains


Antenna Innovation What could be achieved?

• Multi dimensional applications covering • Optimisation of different access technologies in same freq band • Optimising individual RF channels within same standard • Enhancing cell throughput on network or cluster basis.

Spectral Efficiency

Techniques

Elevation Beamforming


Antenna Hardware Evolution?

• There are Active Antennas which are purely active, offering 1x box at the top of the mast.

• Then, there’s a roadmap for Active Antennas which also will promise adaption of the (vertical) beam pattern on a per Physical Resource Block (PRB) or user resolution basis.

• The latter being a focus of a lot of OEM vendors right now; fits with slim line antennas for Western markets.

• Quintel are offering a complimentary solution delivering smart (adaptive) coherent Beamforming in radio channels where full complex vector control of each antenna element isn’t necessary.

Bas

eban

d/D

AC

/RF

Sta

ges

Opt

ical

Fib

re

Active Adaptive Antenna

Baseband Server

Innovation: Quintel

Multi-Band Capable Offers Active/Smart

antenna type features Completely Passive

Opt

ical

Fib

re

Baseband Server

Qui

ntel

Cor

pora

te F

eed

BB-RF

Dual-PA IRU

Full Complex vector control at each element

(Fully Active Adaptive Array)


Qui

ntel

Cor

pora

te F

eed

Net

wor

k (+

45o )

Cor

pora

te F

eed

N

etw

orks

Qui

ntel

Cor

pora

te F

eed

Net

wor

k (-4

5o )

Pha

se

Shi

fters

T R T T R T

Dynamic (adaptive) tilting (per user) for LTE Uplink Independent Static Tilt for LTE Downlink

+45 -45

LTE eNB (2T/4R Configuration)

T R T R

RxD3 RxD4

R

A Solution for Spectral Efficiency MultiWav - Adaptive Elevation Beamforming (Uplink only)

Tx/Rx2 Tx/Rx1

• Connecting a 2T4R Base Station as shown with 4-way Maximal Ratio Combiner (MRC), rather than usual 2-way MRC.

• MRC algorithm simply applies weights and phase delays to the 4x Rx inputs to maximize C/I, and will do this on a per channel (per user) basis at baseband.

• Applying phase delays to within each of the Rx differential pairs is simply creating a coherent beam (tilt) toward/from each user/terminal, and then applying phase/weights between +45 and -45 is then standard 2-way Rx diversity.

LTE Downlink LTE Uplink (Adaptive)

T R

4-Way MRC

T R

Σ

R



Qui

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45o )

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LTE (R9+) 4T4R

+45A +45B -45A -45B

Beamforming in Elevation across each A&B ports

Spatial Multiplexing up to Rank 2 across +45 and -45 BF pairs

Dynamic Beamform/Tilting for LTE

Interference

UE

A Solution for Spectral Efficiency MultiWav - Adaptive Elevation Beamforming (Up & Downlink)

Can be a 2T4R eNodeB (giving Uplink adaptive coherent Beamforming)

0

10

20

30

40

50

60

0 100 200 300 400 500

LTE 2GHz/20MHz 2x2 Config Flat Earth 3x19 cell geometry

(25m Ht x 500m Cell Radii) Monte-Carlo Simulation

Mbps (y) vs. Dist in m (x) Blue – No Elevation BF

Red – With Elevation BF


Uplink throughput for Azimuth (CLA-2X) and

Elevation (Quintel) plane adaptive Beamsteering

Quintel technology has been researching this area and has developed a novel antenna design which effectively introduces a new 4x port Base Station antenna option for consideration. It is logically the same as the CLA-2X antenna configuration but performs coherent Beamsteering on a per UE or UE group basis in the Elevation plane, rather than Azimuth plane, and is based on a completely passive traditional column array, rather than an Active phased Array solution.


Qui

ntel

Cor

pora

te F

eed

Net

wor

k (+

45o )

Cor

pora

te F

eed

N

etw

orks

Qui

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Cor

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Net

wor

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5o )

Pha

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Shi

fters

9 8 9 8 9 8 9 8

GSM900, UMTS900

LTE800

4xTx/Rx

+45 -45

Dynamic Beamform/Tilting for LTE800 RET for 900

2xTx/Rx

• One 4T4R plus one 2T2R base station example shown

• Quintel advantage is that a single column array lends itself to dual-array (dual-band) topology readily. A side-by-side column array (conventional Azimuthal Beamforming) may prove difficult to make dual-band.

• Quintel can also offer our conventional independent (static) tilt for legacy services as illustrated left, as per our MultiServ product approach.

• Potentially, beamforming in elevation could prove more effective than beamforming in Azimuth, due to the fact interference comes from one direction (the horizon) rather than multiple directions as in Azimuth.

Quintel Elevation Beamforming Antenna Legacy support plus Adaptive Elevation Beamforming

Space Efficiency Techniques


And


Thank You!

When wireless is pushed to the limit the answer isn’t more of the same

The answer is more innovation

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