Wind Turbine Cellular Systems
The Problem
Rural communities and areas often
find mobile-phone service to be limited in options and availability. One can look at coverage maps of the many
cell-phone service providers to see that there are large areas of the United
States, typically rural areas with little population, where cell-phone service
is not available. For the service providers, placing towers in those rural
areas is an expensive investment with low likelihood of a return
While
mobile-phone service is sparse in rural communities, these same areas are being
“populated” with wind farms to generate clean (i.e., no carbon emissions)
energy. Wind turbines are typically,
though not exclusively, located on top of hills in rural and remote locations
in open areas to maximize the capture of wind energy and around 90 meters in
height
The
Solution
An
omni-directional radio frequency (RF) antenna for receiving and transmitting
cell-phone communication data is on each blade of a wind turbine. Each RF
antenna has a wired connection that passes from the antenna through the turbine
blade to the connection with the main shaft. At turbine blade’s connection
with the wind turbine’s main shaft, the wired connection from the antenna is
attached to a slip ring which, in turn, is connected to a radio unit
The Primary
RF antenna is integrated within the turbine blade. In some options,
particularly large turbine blades where the turbine blades are large enough that a person is
able to stand inside, the integration may include mounting an antenna in that
space inside of the turbine blade. In alternatives, particularly with
smaller turbine blades where it would not support mounting an antenna
internally, the antenna may be integrated with the turbine blade
material. In the latter instances, the antenna is not exposed at the surface; at least some of the turbine blade material
will cover the antenna. In either instance, the RF antenna is formed
in dimensions to the available space and/or shape of the turbine blade into
which it is integrated. Irrespective of the manner in
which the antenna is integrated into the turbine blade, the design does
not have any effect on the aerodynamics of the turbine blades or their
operation as part of the wind turbine
While
turbine blades vary between 18 and 100+ meters in length, the RF antenna is
typically located between 3 and 8 meters from the connection to the wind
turbine’s main axle and center of rotation for clearance plus
diversity. Generally large wind turbines utilize three blades as the
most efficient, though the design is not limited to having this. Each RF
antenna may correspond to operating on distinct frequencies and cellular
formats from the antennae of other turbine blades of the wind turbine (i.e.,
supporting distinct cellular providers). However
typically a wind turbine will support only one cellular provider, i.e.,
having all turbine blade antennae configured to support the frequency(ies) and/or format(s) of a single cellular provider
The primary
RF antennas use the lower of frequency bands available
with highest power and reliability to enable the widest area of service. The
same antennas can be used with higher frequency bands also where possible, or
these bands could have more directional antennas mounted on the pole below the
wind turbine head, either way using carrier aggregation to still provide wide
area service but with much enhanced localized capacity and bandwidth/speeds.
Cellular
frequencies of operation (in USA) – many pros and cons for all:
•
Licensed
low band (< 1GHz)
•
Licensed
mid band (2 to 3GHz)
•
CBRS
3.5GHz shared band, variable service as governed by SAS
•
New
bands in 4/7/8GHz will probably have portions licensed and shared
By far the
best is a combination of 2 or more bands with carrier aggregation for the
widest coverage range along with highest capacity and best user experience. A
multi-band solution with higher band sectored antennas below the nacelle is the
preferred solution. Having sectored mid band (2 to 7GHz) antennas will have
higher gain than omni antennas on the blades but with higher propagation losses
real coverage will be less. But these higher bands would be used with carrier
aggregation to supplement the overall service nearer the tower with better
performance with higher bandwidth, but further out will revert to just the low
band service
In addition with the blades spinning they will give less
consistent service for mid band frequencies, when a blade is in front of an
antenna service in that band might be restricted so will then just rely on the
blade low band service. In extremes when there is no wind and the blades are
stationary if they happen to be in front of some antennas these might be
effectively unavailable, services will be maintained but lower bandwidth in a
certain direction for some time
The
effective coverage area, or range, of a typical wind turbine cellular site can
vary a lot, but is really down to these 4 key factors:
• Frequency band of operation, higher
frequencies don’t go as far due to atmospheric limitations
• Height, both of the base
station antenna above the ground but also where the tower is located
• Effective power of radio units, this is
usually governed by regulatory requirement to allow coordinated coexistence of
service providers, and also include the effective gain
of antennas
• Quality of service (QoS) required, simply the
desired signal strength or data throughput criteria, the higher of either
effectively gives a smaller range
In summary
using a low-band frequency with full power available on a normal site can give
very good quality service for over 20 miles or 30 km
The
cellular system of the wind turbine may be powered by batteries charged by the
wind turbine in which the cellular system is incorporated for continual
operation even when there is no wind
In various
options the antenna radio unit is connected to a microwave radio of any
applicable band that communicates with another cellular base station site and
to its core network. The microwave antenna is located on or near the wind
turbine’s tower below the lowest extent of turbine blades
so they do not interfere with the communication between it and the next site
when rotating
Alternatively the system may communicate with other cellular base stations and
core network via physical instead of a microwave connection. For example,
a system may include a controller that communicates data over a fiber optic or
wired connection, or a combination, or even satellite
Summary
Systems
provide very wide area coverage as generally on high sites and tall towers to
fill in coverage in hard-to-reach areas and roads that normally wouldn’t be
possible either due to citing regulations or not being economical so no need for new sites and associated zoning, regulatory
approvals and thus no environmental or visual impacts
Much
improved customer experience with seamless service and no dependence on
limitations and expense of fill-in roaming or satellite coverage alternatives
Multi-technology
capable so can be used for 4G, 5G and 6G when available, and any combinations.
Can operate in any frequency bands, low band (<1GHz) preferred for best
coverage along with mid band (2-7GHz) for capacity, and ORAN, VRAN,
multi-operator, private network and neutral host compatible
Equally
applicable for new wind turbine builds but also when doing upgrades such as
replacing the blades which fatigue and are usually replaced every 10 to 20
years to prevent consequences
Can be used
both inland and offshore, individual sites or in windfarms
with high reliability, low maintenance and very stable power from local
batteries charged by the wind turbine
Scaled down
versions can be used for localized wind turbines for industrial, residential
and other areas as Small Cells for added coverage, capacity
and in building penetration, primarily in higher frequency bands
Flexible
connectivity with other sites and core network via fiber, copper, microwave or
even satellite. And totally transparent and complementary to wind turbine
primary role of generating clean energy
Ultimate green cellular
mobile coverage solution for rural and difficult to cover areas
A typical
rural site covering remote roads and small villages and power far beyond
Patents
pending - 63/651,895 and PCT/US25/30399
Based in
Arizona USA, for more information contact via
https://www.facebook.com/malachite.communication/