The WMP evaluates wireless coverage throughout the nine study
areas by:
•
|
Identifying, assessing, cataloguing and mapping exiting transmission
equipment; and
|
•
|
Designing an engineered search radii template and applying it
over the jurisdictional boundary of the City and County to evaluate
theoretical build-out conditions; and
|
•
|
Forecasting future infrastructure needs based on the status
of the existing deployments’ population trends and gaps in network
coverage.
|
(Ord. 4703, 6-1-16)
Prior to the granting of the cellular licenses in 1980 for the
first phase of deployment, the United States was divided into 51 regions
by Rand McNally and Company. These regions are described as Metropolitan
Trading Areas (MTA). The spectrum auction conducted by the Federal
Government for the 1,900 MHz bands for 2G (PCS) further divided the
United States into 493 geographic areas called Basic Trading Areas
(BTA). Mesa County (including all incorporated and unincorporated
areas) is located in the “Denver” MTA (a.k.a. MTA 22)
and the “Grand Junction, CO” BTA (a.k.a. BTA 168). Service
providers acquire the rights to deploy their networks by service area
and range of spectrum frequency.
Per Section 704 of the Telecommunications Act of 1996, all service
providers will require uninterrupted and continuous handoff service
throughout the City and County. There are 11 known service providers
that will each want to compete for the subscriber base in and around
the City of Grand Junction and Mesa County. Each of these wireless
voice and data providers will need towers and/or elevated antenna
mounting locations to improve network coverage and capacity that will
result in an ongoing need to deploy more infrastructure, especially
in areas of greater residential density.
The following service providers have purchased licenses to serve
all incorporated and unincorporated areas of Mesa County in the lower
frequency ranges of 700 – 900 MHz: AT&T; Access 700,
LLC, Dish, T-Mobile, Union Telephone (Union Cellular) and Verizon
Wireless. Personal Communications Services (PCS) licensees and service
providers for wireless phone and broadband operating in the higher
frequencies of 1,700 – 2,700 MHz bands include: AT&T
Wireless, Atlantic Wireless, Cleartalk, Clearwire Spectrum Holdings
III, LLC, Commnet Wireless, LLC, Leaco Rural Telephone Cooperative,
Inc., Sprint, T-Mobile and Verizon Wireless.
Most network service providers do not own the antenna mounting
structure on which they attach their equipment. Tower companies typically
construct and own the monopole, lattice or guyed towers and lease
space on the towers to service providers. A service provider may also
contract with a tower builder to construct a tower in a particular
location and once the facility is constructed lease space on the newly
constructed tower from the tower owner. Throughout Mesa County there
are a number of tower companies who own and lease their vertical real
estate to the service providers including American Tower Corporation
(ATC), Crown Castle International (CCI), The Leasing Company, SBA
and others.
(Ord. 4703, 6-1-16)
(a) Tasks A and B of the scope of services include research to gather
antenna and tower location data in order to develop initial transmission
equipment location base maps. The City and County GIS Departments
provided some existing facility locations to CityScape. Additional
infrastructure locations were obtained by CityScape from tower owners
and various databases including the FCC’s database. Once the
sites were mapped, each site was individually assessed and validated
for:
(1) Physical location of existing telecommunications facilities currently
within the defined study areas;
(3) Ownership of the infrastructure; and
(4) Potential for future provider equipment co-location on the existing
structures.
(b) The assessment included an in-person visit to each of the transmission
equipment locations. While there are many types of antennas used for
a variety of communication purposes throughout the defined study areas
(dispatch, wifi hot spots, broadcast etc.), CityScape generally only
included infrastructure sites in the inventory that met the following
criteria:
(1) Towers and base stations that currently support wireless and/or cell
coverage and broadband infrastructure as referenced in the EDP;
(i) Personal wireless service facilities (PWSF) meaning any staffed or
unstaffed location for the transmission and/or reception of radio
frequency signals or other wireless communications, including commercial
mobile services, unlicensed wireless services, wireless broadband
services, and common carrier wireless exchange access services as
defined in the Telecommunications Act of 1996, and usually consisting
of an antenna or group of antennas, transmission cables, feed lines,
equipment cabinets or shelters, and may include a tower. The following
developments shall be deemed a PWSF: new, replacement, or existing
towers, public towers, replacement towers, co-location on existing
towers, base station attached concealed and nonconcealed antenna,
concealed towers, and nonconcealed towers (monopoles, lattice and
guyed);
(2) Towers and base stations with microwave dish antenna because of their
potential to promote co-location;
(3) Broadcast towers because of their potential to promote co-location;
and
(4) Towers in remote locations because of their potential to either promote
co-location or to be reconstructed to accommodate future co-locations.
(c) The wireless infrastructure assessment identified 142 existing transmission
equipment sites that meet the prescribed criteria within the nine
study areas. Also included in the assessment are 10 sites within a
1.5 mile perimeter of the County boundary. These locations were included
because their signals may affect service within the defined study
area. Fifteen sites contain multiple towers so the number
of towers exceeds the total number of sites.
(d) Table 2 provides a summary of the total number of types of antenna
mounting structures found throughout the study areas and Table 3 identifies
the ownership of the infrastructure as of January 2016.
Table 2: Type of Infrastructure Summary
|
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TYPE OF INFRASTRUCTURE
|
TOTAL
|
---|
Lattice Tower
|
69
|
Guyed Tower (includes 2 guyed monopoles)
|
47
|
Base Station (rooftop or water tank)
|
16
|
Monopole Tower
|
14
|
Concealed
|
6
|
Self Support
|
5
|
Wood Pole
|
4
|
Approved But Not Constructed
|
4
|
TOTAL
|
165
|
Table 3: Owner of Infrastructure
|
---|
INFRASTRUCTURE OWNER
|
TOTAL
|
---|
Others (independent tower owners and/or local businesses)
|
46
|
Other Government Agencies (City, County, State, BLM, DOI)
|
17
|
Broadcast Companies
|
20
|
SBA
|
19
|
Unknown
|
19
|
American Tower Corporation
|
7
|
Crown Castle International
|
5
|
Verizon Wireless
|
5
|
The Leasing Company
|
3
|
AT&T
|
2
|
TOTAL
|
142
|
(Ord. 4703, 6-1-16)
Wireless location search rings are usually calculated to be
circles approximately one-quarter of the radius of the proposed cell.
In practice it is fairly simple to determine whether the calculated
search ring radius is reasonable. The distance from the closest existing
site is determined then halved and a handoff overlap of about 20 percent
is added. One fourth of this distance is the search ring radius. Generally,
in areas where signal coverage is the objective, taller towers allow
the antenna to service a larger geographic coverage area and provide
more potential for equipment co-locations by other service providers.
Shorter tower heights limit the geographic coverage area and reduce
the number of possible co-locations resulting in a greater number
of towers required within each search ring.
The search area or search ring for new wireless infrastructure
is part of a package provided to a site search consultant who looks
for property that can be leased to accommodate the required wireless
antenna and related infrastructure, whether that be a new tower, a
rooftop or other existing structure. From an engineering perspective,
any location within the search ring is considered to be acceptable
to the provider after considerations are made for terrain and sometimes
population distribution. The relative location of the selected property
to the ideal location within the search ring will dictate the required
antenna height.
(Ord. 4703, 6-1-16)
Search ring calculations for the low and high band frequencies
are shown in Tables 4 and 5. The tables utilize the “Okumura-Hata”
propagation path loss formula for low band, and the “COST-231”
formula for high band. Maximum coverage radii for typical in-vehicle
coverage is calculated for various tower heights, reduced by 20 percent
to account for a reasonable handoff zone, then divided by four to
obtain a search ring radius for each tower height. For example, according
to the information in the following tables, a low band antenna mounted
at the 100-foot elevation would have a search ring radius of 0.72
miles, and a radius of 0.36 miles for high band antennas.
Table 4: Okumura-Hata Coverage Predictions for 700 –
900 MHz
|
---|
ANTENNA MOUNTING HEIGHT
|
50'
|
100'
|
115'
|
150'
|
---|
Radius, miles
|
2.53
|
3.6
|
3.88
|
3.91
|
Allow for handoff
|
2.03
|
2.88
|
3.1
|
3.6
|
Search ring, miles
|
0.51
|
0.72
|
0.78
|
0.9
|
Table 5: COST 231 Coverage Predictions for 1,700 –
2,100 MHz
|
---|
ANTENNA MOUNTING HEIGHT
|
50'
|
100'
|
115'
|
150'
|
---|
Radius, miles
|
1.33
|
1.82
|
1.95
|
2.32
|
Allow for handoff
|
1.07
|
1.46
|
1.56
|
1.79
|
Search ring, miles
|
0.27
|
0.36
|
0.39
|
0.45
|
Tables 4 and 5 represent theoretical predictions and each facility
will vary somewhat from these estimates.
(Ord. 4703, 6-1-16)
Taller structures (towers, rooftops, and water tanks) may offer
more opportunity for co-location which could theoretically decrease
the number of additional towers and antennas required in an area,
but capacity issues may overcome the advantage of the taller structure.
Each potential structure must be subjected to a radio frequency (RF)
engineering review to determine the extent to which height will increase
co-location opportunities. In geographic areas where there is a large
wireless phone subscriber base or terrain concerns, build-out plans
may require lower antenna mounting elevations. Antennas located at
higher points on the support facility are more common in rural areas.
In some cases, wireless providers limit the antenna placement height
in more populous geographic areas because they need multiple antennas
installed at differing heights on a single tower to target specific
locations or to reduce the potential for interference with other equipment
on the structure.
CityScape is often asked to estimate how many towers and base
stations it will take to cover a particular geographic area. Because
of the number of factors that might affect the coverage for a given
service provider, CityScape uses theoretical root mean square (RMS)
maps to help the client visualize the number of antenna locations
that may be necessary to provide wireless communications coverage
for a given geographic study area. This hypothetical network identifies
the minimum number of tower or base station locations required for
one service provider to provide complete coverage without any considerations
for terrain, vegetative cover or subscriber base.
One of the key variables affecting the theoretical coverage
analysis is the assumed height of the antenna on the tower or structure.
CityScape reviewed the existing tower inventory and applicable height
regulations for the City and County and determined the average tower
height of the towers used for wireless telecommunications purposes
to be around 118 feet. Therefore, the antenna mounting elevation of
118 feet was chosen for the development of the theoretical RMS coverage
maps.
According to the Okumura-Hata propagation path loss formula
coverage for low frequency (i.e, 800 MHz), a reasonable coverage area
for an antenna mounted for cellular deployment at 118 feet on flat
terrain is about 3.88 miles from the antenna. Referring to the “COST-231”
formula for 1,900 MHz a reasonable coverage area for an antenna mounted
at 118 feet for a high band site on flat terrain is approximately
1.95 miles. The coverage reduction from 3.88 miles to 1.95 miles reflects
the variable change from low to high band frequency.
Figures containing the theoretical maps for both low and high
band frequencies, for each study area, can be found in Article III
of this chapter, Study Areas.
(Ord. 4703, 6-1-16)
Mapping the existing antenna sites creates a base map from which
observations and analysis can be derived relative to current and future
deployment patterns. Generally, most of the wireless infrastructure
in Mesa County is located within and around the more urban study areas,
particularly the City of Grand Junction, Lower Valley, Palisade, DeBeque
and the I-70 corridor. Whitewater is the only rural study area with
a larger concentration of infrastructure because of the Highway 50
corridor and the larger subscriber base in that area. Minimal or no
wireless network coverage was found for the undeveloped areas within
the County’s zoning jurisdiction.
Maps of the existing and proposed tower infrastructure and a
site data table are provided in Article III of this chapter, Study
Areas, for each individual study area. A complete listing including
photographs of the verified infrastructure is provided in the January
16, 2016, inventory document.
(Ord. 4703, 6-1-16)
The next step in the network evaluation process is to examine
the coverage from all known antenna locations to identify gaps in
network coverage. For the purposes of this WMP, CityScape has chosen
to use theoretical composite propagation modeling.
Propagation modeling is a process that uses mapping techniques
to illustrate the expected level of cellular coverage theoretically
provided from one or more antenna sites, based on reliable service
factor most of the time. Relative signal strength is displayed in
color bands to illustrate the anticipated coverage provided by each
antenna. Signal strength, in this application, is a term used to approximate
the level of operability and quality of service of a wireless device.
The stronger the signal at the mobile device the better functionality
it will have. A reduced signal lessens the quality of the call or
data usage and can result in dropped calls, lack of or slow connectivity
or frozen video. Distance between the mobile device and facility,
intervening obstructions such as trees or buildings, and whether or
not the subscriber is indoors or outside are all significant factors
that affect signal strength and quality of service.
The level of propagation signal strength is shown for low band
services in yellow and high band services in blue. These colors represent
a generally acceptable and reliable signal level for indoor use for
both low and high bands of service. Indoor usage is used as the lowest
acceptable service threshold due to the signal loss that occurs from
building penetration when compared to in-vehicle or outdoor pedestrian
usage. Generally, the closer the mobile device is to the antenna,
the more reliable and acceptable the service. The further the mobile
device is from the antenna, and the closer it is to the edge of coverage,
the more prone it is to service degradation when cellular usage on
the tower becomes saturated or environmental conditions vary.
Theoretical composite propagation maps include terrain, vegetative
cover, and current population density variables in the coverage calculations.
The antenna mounting elevation is assumed to be at the highest mounting
elevation of towers and base stations where the heights are known
and at the average height of 118 feet for structures of unknown height.
The resulting composite maps are included in the analysis provided
in Article III of this chapter, Study Areas.
(Ord. 4703, 6-1-16)
Service providers use base population estimates and subscriber
data to design their network, to decide how many antennas are needed
and to determine how far apart antennas should be located. Depending
on the number of wireless subscribers connected to a given antenna
(i.e., the local wireless penetration rate) and each device’s
usage, a given site has the capacity to provide service to between
1,750 and 2,500 devices. As the number of wireless devices increases
and/or usage increases (particularly for more data intensive applications
like social media, music and video streaming), the geographic area
covered by the antenna decreases and the number of subscribers served
by the facility must be reduced into order to avoid overloading the
system and impacting data transfer speeds. Based on the expected increases
to both subscriber rates and usage over the next 10 years, the current
facility design model of 1,750 to 2,500 devices per site will shrink
to between 500 to 1,200 devices per site, depending on the provider,
services offered, and the number of overall subscribers. Because of
this shrinkage, the number of towers and base stations needed to provide
coverage to the same geographic area will increase dramatically over
the 10-year period covered by this study.
The shrinkage in propagation signal pattern resulting from projected
technology changes, increases in subscribers, and the usage demand
caused by new applications is shown in a second set of composite maps
included in Article III of this chapter, Study Areas. These maps illustrate
how the network coverage patterns for a single high frequency service
provider are expected to shrink over the next 10 to 15 years.
The resulting areas with no service, gaps in service, and average/acceptable
service are also areas of particular planning interest in the coming
years. Comparing the current coverage maps with the 10-year projection
in undeveloped areas shows minimal change in future demand. However,
comparing maps in more urban areas shows that coverage gaps will become
larger if the network infrastructure is not expanded. The resulting
geographic areas with marginal to no service are of particular planning
concern over the next 10 to 15 years.
(Ord. 4703, 6-1-16)
CityScape has estimated, by study area, the number of sites
that may be needed for planning purposes over the next 10 to 15 years.
The estimates are based on calculations taking into account expected
changes in population density, subscriber base and usage, daily transient
movement through the given study area and how many calls a tower or
base station may simultaneously serve at any given time. The projections
include coverage, capacity, and broadband network objectives and take
into account the variables of terrain, population and proposed maximum
infrastructure height variables. The projection model includes all
known existing antenna support structure locations (towers, rooftops,
tanks and broadcast towers) for maximum co-location efficiency that
reduces the number of new towers required within a given geographic
area. These projection maps are also provided in Article III of this
chapter, Study Areas.
While the launch date of 5G is unknown, it will happen within
the next 10 years and will provide true high-speed data transfer rates
in excess of today’s broadband download standard of 25 Mbps.
With wireless broadband speeds available on 5G networks, most all
types of communications (from voice to computer data) and entertainment
(from cable/satellite TV and radio to first run motion pictures) will
be available over wireless systems. Few new sites will be built to
provide new coverage but to resolve over-capacity issues in an area
currently served. Since 5G networks will utilize frequencies much
higher than today’s 4G networks, coverage areas will be more
compressed around the antenna source. Most new towers will be built
to place antennas close enough to the end user to deliver the high
frequency and high bandwidth speeds needed to meet broadband demands.
Construction of the new sites needed to keep up with advancing
technologies and customer demand is not expected to happen evenly
throughout the study area. However, over the next 10 to 15 years the
cities and County should anticipate that up to 40 new tower or base
station sites will be needed. The more populated areas will likely
see the development of “small cell” sites. Small cells
are individual “nodes” that typically consist of concealed
antennas located relatively close together on shorter tower or support
structures. For example, small cells can be added to existing light
posts and placed every few hundred feet, or may be concealed on shorter
buildings. There are many options for small cell design that allow
this infrastructure to be connected to form a “mini network”
that can handle the high capacity required in the more urban areas.
The cities and County can easily anticipate five to eight co-locations,
upgrades or antenna modifications (in any combination) per year over
the next 10 years based on expected changes in population density,
subscriber base and usage, transient movement through the City and
County and how many calls a tower or base station can simultaneously
serve at any given time.
(Ord. 4703, 6-1-16)