Optimizing Backhaul for Picocells in 4G Networks
Amir Makleff
President and CEO
BridgeWave Communications
Cell Size Evolution
Bit Rate
1 Gbps
-
-d
en
r
T
--
-
Macrocells
Microcells
100 mbps
Picocells
10 mbps
100 m
1 Km
Distance
10 Km
 Distances and bit rates are still being debated
 The general trend of higher bit rates/shorter distances is
widely recognized
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www.bridgewave.com | 1-866-577-6908
2
Small Cell Drivers
 Macro Network Holes
 Network holes between Macro Base Stations, originate from geography,
building layout or legacy network planning
 These “holes” yield slow data rates and dropped calls
 Solution:
 Pinpoint deployment of picocells in the middle of the Macro holes, to light
up hard to reach strategic locations.
Small Cell Backhaul Challenges
 Dense urban areas
 Large number of nodes to achieve coverage
 Different types of nodes in a variety of locations:
 In buildings
 Roof tops
 Street-level
 Light or utility poles
 High capacity
 Propagation in urban canyons
 Aesthetic fit (inconspicuous)
 Cost-effective
Small Cell Backhaul Requirements
 Low cost of equipment + installation
 Low Opex/recurrent fees (e.g. license)
 Small deployed footprint
 Aesthetic fit in urban environments
 Bit rates expandable up to 1 Gbps
 To support mesh and daisy chaining
 Short deployment lead time
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www.bridgewave.com | 1-866-577-6908
5
Millimeter Wave Backhaul
 Point-to-point millimeter wave radios have some
unique advantages for mobile backhaul:
 Abundance of spectrum
 High capacities
 Attractive licensing & highly-directive transmission
 Natural immunity to interference
 High frequency reuse
 Minimal frequency planning
 Short wavelength
 Small size of hardware and integrated solutions
 Quick deployment
 Low CapEx / OpEx
mmW Spectrum
 A relatively recent addition to fixed PTP frequencies:
 V-band (“60GHz”) 7GHz (57-64GHz)
 Unlicensed (e.g., USA, UK)
 E-band (“80GHz”) 10GHz (71-76GHz and 81-86GHz)
 Light-licensing (e.g., USA, UK)
 Full licensing (e.g., Germany, Ireland)
mmW Propagation
 60GHz:
 Absorption of O2 ~14dB/Km
 Also rain
 1-2Km for 1Gbps links @5’9s
 80GHz:
 Rain
 2-4Km for 1Gbps links @5’9s
 Neither is impacted by:
 Multipath fading due to narrow
beams and relatively short
links
 Fog (<0.4dB/Km)
60 GHz
Excessive rain
150mm/h
Heavy rain
25mm/h
Fog
Drizzle
0.25mm/h
80 GHz
mmW Directivity
 High gain and narrow beam-width achieved with small
antennas
5.8 GHz = 1,140’ wide @ 1 mi
 Typical examples:
60GHz

5mm
12cm antenna 3dB / GA
1.0 / 35dBi
25cm antenna 3dB / GA
0.5 / 40dBi
 Implications:
 Security
 Low probability of detection (LPD)
 Low probability of intercept (LPI)
 High interference immunity
 High frequency reuse
 “No” multipath
60 GHz = 128’ wide @ 1 mi
mmW Frequency Reuse
 Frequency reuse facilitated by:
 Narrow beam width
 Oxygen absorption at 60GHz.
 At 60GHz, an infinite linear cascading of links may be
achieved using only one pair of FDD frequencies and 2
polarizations:
u
d
"West"
"East"
A
B
C
D
E
Repeatable pattern
 E.g., d=300m -> u=1500m -> CCI -20dB
F
The Aesthetics Challenge
 Traditional direct mount and parabolic antennas are
OK for rooftop / mast deployment
 Street-level deployment requires a different approach:
 Aesthetic
 Concealed / disguised
 Small footprint
Concept Testing
 Tier-1 carrier field trial over several months

mmW Backhaul for Small Cell Revisited
Excellent scalability
 Scalable capacity >1Gbps
 Distance scalable from picocell to macrocell
backhaul
 Fast and simple deployment
 Good frequency reuse
 Good interference immunity
 Minimal frequency planning
 Good fit for urban environment
 Aesthetic, “concealed” solution
 Small footprint
 Low Cost
 Low Total Cost of Ownership per bps
 Minimal OpEx and recurring fees (e.g.
license)
 Challenges
 Limited applicability in rural environments
and other long-link scenarios
Conclusions
 Small cell backhaul requires a combination of
multiple solutions: “Backhaul Toolbox”
 Including fiber, microwave, millimeter wave, etc.
 Millimeter Wave radios offer distinct advantages for
small cell backhaul:
 High capacity links
 Abundance of spectrum
 Good urban fit
 Fast and inexpensive deployment
 60GHz solutions ideal for small cell deployments and
is a proven technology for similar applications
© BridgeWave Communications
www.bridgewave.com | 1-866-577-6908 1-408-567-6900
14
Thank You
Amir Makleff
President & CEO
BridgeWave Communications
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