A look into why and how a wireless provider would set up a new cellular or PCS network. Original publication date: October 1999.
Introduction
A good portion of this web site is devoted to mapping locations and the identification of cellular transmission equipment across Canada. This includes the maps for Victoria, Vancouver, Nanaimo, Kelowna, Whistler, Windsor, Halifax, plus new maps planned for the near future (e.g., Edmonton and Calgary) as well as the Cellular Equipment Identification Guide. Although I show each wireless provider's locations on these maps, I do not mention the steps that each of the wireless providers took to establish their network in each of these locations. This article deals with why a wireless service provider would set up a wireless network in a particular market and the steps required to setup a new network.
The Canadian Wireless Market
Within the last three years the wireless market has seen a significant increase in the number of subscribers. Over a decade ago wireless or cellular phones were restricted to either business users or people who were willing to pay over $1000 for a phone (Figure 1) plus a hefty per minute usage charge. These first cellular phones were relatively bulky with some of the older models requiring a suitcase to be carried around with the phone. Later phone models eliminated the suitcase requirement, were able to fit into a briefcase, but definitely would not fit into your pocket.
In the last few years several new wireless phone manufacturing companies have entered the market. This has introduced heavy competition into the production of smaller models, dual technology and dual frequency capable models, and handsets with 'smart' features such as email and internet browsing. In turn, the price of these handsets have dropped significantly as well. Most wireless handsets now cost in the range of $100-800, significantly less than the $1000-2000 you would have paid a decade ago for something the size and weight of a brick. Still today, most consumers would not be willing to pay $800 for a wireless phone. To encourage people to buy cellular phones, the wireless service providers subsidize their handsets by 50 to 100%. This is why most wireless phones cost in the range of $0-200, which is nowhere near their actual cost to the wireless service providers.
Figure 1. Cellular phone advertisement from 1990. Who would pay this price for a cell phone these days?
Everyone seems to have a wireless phone these days. Well, not everyone: as of mid-1999, approximately 20% of Canadians have wireless phones. This percentage is predicted to reach 50% within the next five years. More and more people are discovering the benefits of owning a wireless phone to keep in touch with others and for the added safety. In turn, the wireless service providers are pouring significant amounts of cash into building and expanding their wireless networks so that they can lure more and more Canadians into the wireless market.
Figure 2. Canadian wireless phone companies. Mobility Canada is a group of 15 provincial, territorial, and city phone companies that operate in distinct markets only. Rogers (used to be Cantel), Telus Mobility/Clearnet, and Microcell operate nationwide.
Across Canada there are essentially four wireless phone companies (Figure 2). Both Mobility and Rogers have been around since the mid-80's, whereas Microcell is newer to the wireless market. In the mid-1990's Industry Canada allocated a new spectrum for the use of wireless communications, and these three different companies successfully obtained licenses to build new networks in the 1900 MHz band for Personal Communication Services or PCS.
Prior to this release of the 1900 MHz band, both Mobility and Rogers had built analog or AMPS networks in the 800 MHz band. The initial analog network builds were focused on the larger cities (e.g., Vancouver, Toronto, Montreal) and then smaller cities and communities were added. Over the course of a decade both companies have been able to build very large analog networks serving most major Canadian cities and communities plus several of the major highways in between.
When the new PCS band was allotted, both Mobility and Rogers had a choice of either 800 or 1900 MHz in which to offer their new digital wireless services. To fulfill licensing agreements, they are required to establish a 1900 MHz network by December 31st, 1999 in all regions of the country.
In British Columbia, both Telus Mobility (used to be BC Tel Mobility and Clearnet) and Rogers (used to be Cantel AT&T) made the choice of first building an 800 MHz digital cellular network since they could use many of their existing analog towers to quickly establish a new network. The main disadvantage of this strategy was that each company has a limited bandwidth at 800 MHz. By establishing an 800 MHz digital cellular network there is a loss of some of the available bandwidth for analog services using the same frequency.
Microcell needed to set up a new network in the 1900 MHz band, which among other problems, included a greater number of tower sites than those required for 800 MHz. In BC, both Telus Mobility and Rogers are now just starting to set up their 1900 MHz networks to fulfill licensing agreements.
Wireless networks in Ontario are a different story: both Bell Mobility and Rogers offer only digital services in the 1900 MHz band and the 800 MHz band is for the exclusive use of analog services. Part of the reason behind this different setup may be due to the higher network load on both the 800 MHz and 1900 MHz bands. In areas with a lower number of users there is likely enough bandwidth available in the 800 MHz allocation to handle both analog and digital cellular network subscribers.
At present all four wireless providers offer digital services in most major Canadian cities: Victoria, Vancouver, Calgary, Edmonton, Toronto, Ottawa, Montreal, and Quebec City. In B.C., both Telus Mobility and Rogers also offer digital services in several smaller cities. As Telus Mobility and Rogers start to build their 1900 MHz network, users of this new network will be initially limited to major centres (Victoria and Vancouver), unless their particular handset supports dual band services (e.g., the Nokia 6185/8 supports both 800 and 1900 MHz CDMA as well as 800 MHz AMPS; Figure 3). The cell phone industry is now starting to introduce handsets that support dual technologies and frequencies so that customers may seamlessly use their phone in different market areas using different technologies and frequencies.
Figure 3. The Nokia 6185/8 supports dual-frequency CDMA as well as AMPS wireless technologies.
Wireless Network Components
In a basic form a wireless network consists of three components: the mobile unit, a cellular transmission/reception site, and a mobile telephone switching office (MTSO).
Mobile units are the wireless handsets we use. They contain a transceiver, control circuits, and an antenna.
Cellular sites are what the mobile units 'talk' to. They consist of one or more transmit and receive antennae. Each antennae covers a particular geographical area. If a single antenna covers an entire area it is known as an omni-directional cell. If the cell site contains several antennae, then each antenna is sectorized to provide coverage to a particular area around the cell site. Along with the antenna structures there are connections to the MTSO via either a microwave dish and/or dedicated T1 lines for fast connectivity. The cell site must also contain electronic circuitry to provide a communications pathway between the mobile unit and the MTSO. A wireless service provider may only have one cell site in a small community (Figure 4), whereas they may have hundreds of cell sites in a large urban centre.
The Mobile Telephone Switching Office acts as a coordination centre for all the cell sites within a network. Calls from mobile units are transferred through a cell site to the MTSO, which then transfers the call to the landline telephone network. Likewise, incoming calls to the mobile are passed from the landline system to the MTSO which then pages the mobile unit through the current cellular site that the mobile is 'talking' to.
Seting up a wireless network is no easy undertaking and requires significant funding. A full cell site installation may cost upwards of $1 million. The land or building space that cell sites occupy must be leased, which may require another $5-10K per year. Add to that the leasing of T1 lines, site maintenance and security, electrical requirements, plus the costs associated with running a MTSO. A provider must also supply mobile handsets, provide customer service for their users, advertise and more.
Canada's newest wireless provider, Microcell, will likely not show a profit for several years due to the high costs associated with building new PCS networks from the ground up.
Figure 4. Analog cellular tower in Port Alberni. Often in smaller communities only one tower is required to service an entire area.
How do wireless service providers determine where to setup their wireless networks? These are some of the reasons why they may set up a network in your area:
What licenses they have obtained from Industry Canada for particular regions of the country (e.g., Pacific, Central, Ontario, Quebec, and Atlantic)
Where they stand to make a profit based on the ratio of network maintenance to network usage
Where the competing wireless phone companies are setting up their networks
Available funding. The company may not have enough cash at the present time to build a network in a particular market area
Corporate contracts may influence network setups. This is particularly applicable to the iDEN network used by Telus Mike
Cell Site Coverage
In an ideal environment, cells provide coverage in a radius around a tower or base station. Users of cell phones within that radius will be able to access wireless services. The distance that the radius covers is determined by the power output of the cell site, the amount of background noise, and other environmental interferences. In a real environment, cells do not provide radial coverage due to geographical features and interference from buildings. Places that have a relatively flat terrain will have cells that radiate near-perfect circles of coverage. Cell towers in locations with rough terrain and/or large man-made objects (e.g., buildings) will have distorted cell coverage.
Figure 5 shows coverage from a network of cell sites in an ideal environment. Each cell tower uses a distinct frequency or group of frequencies to 'talk' between the tower and mobile units. In this example, these frequencies have been associated with a number from 1 to 7. Each cell uses their set of frequencies to cover a radius that overlaps adjacent cells. By overlapping cell coverage, mobile users are ensured that as they move between cells that their calls will be passed or handed-off to adjacent towers. You will notice that some of the numbers in this figure are repeated, indicating that a few of the cells use the same group of frequencies. If cells that are reusing groups of frequencies are placed with a fair distance between each other, the wireless provider can make use of the frequency grouping in a new area, thus allowing them to expand their network to any distance, provided that any two cell towers that are using the groups of frequencies do not interfere with each other.
Figure 6. Hexagons used by engineers to depict cell coverage.
In the initial layout of a new wireless network engineers often draw hexagon-shaped cells on maps to simplify layout. Hexagon cells fit easily together and approximate circular cells. Circular cells on maps, although more realistic, are considered messy since their boundaries cross. Figure 6 shows what an engineers' diagram of cell coverage within an area might look like. Both Figures 5 and 6 demonstrate a hypothetical wireless network. Later on we will investigate a real wireless network.
Site Hunting
Once a decision has been made to set up a new wireless network, the first step is to scope out potential locations for cell sites. In larger cities and communities the wireless provider may hire one or more consulting firms to find potential sites and install the wireless equipment.
Scoping out may be done by contractors that are given grids within the city to investigate. Each contractor travels through their assigned grids looking for potential cell sites -- hydro towers, tall buildings, etc. The contractor then makes a note of the location, takes a picture, records the location with a Global Positioning System (GPS) unit, and takes down any other relevant information.
Once all the areas in the city have been investigated, the wireless service provider determines a few different ideal layouts of their cell sites based on a desired coverage area. Site layouts may be chosen based on these individual site merits (not in any particular order):
Availability. Up to approximately 50% of the desired sites may not be available due to lack of space for equipment, failure of approval of the municipality or building/tower owner, or other reasons.
Public concerns over location. Towers are often difficult to locate in exclusive neighbourhoods, new subdivisions, or other places made up of a high percentage of single family dwellings.
Relative cost of leasing space. Some building managers may want to receive a large annual sum for leasing space on their buildings.
Preferred lease. If a number of building locations would work well in an area, the cell company may approach a non- or low-profit building that would better benefit from additional revenue (e.g., retirement homes, hospitals, libraries, public schools, community centres, cemeteries, and churches).
Area zoning stability. If a particular area is to be rezoned in the near future then the tower height may have to be increased or the tower may have to be removed.
Coverage height. The building or tower may be too high or too low. Low sites provide limited coverage (but a tower could be placed on top of the building); High sites have a shadow effect around the building and may interfere with other site signals.
Electrical services. Cell sites require a great deal of power to run. A hydro line must be run to the site or alternatively a generator can be used. Diesel generators are noisy and smelly to run and require regular servicing.
Network services. Cell sites must be connected to the MTSO to operate. This connection can either be via dedicated T1 lines (expensive to install and lease) and/or microwave (cheap, but limited capacity and subject to interference).
Vandalism. Ground sites must be secured to prevent damage.
Expandability. The network may be expanded in the future and certain potential sites outside the initial coverage area may be chosen at this point. This information may be included in the initial network plan and may impact site selection within the coverage area.
Figure 7. Finishing touches on Telus Mobility PCS cells installed on a Microcell-owned monopole in Colwood, BC. This area did not offer any tall buildings or hydro towers so a monopole had to be erected. Wireless providers may share sites to cut costs and minimize public concerns over cellular transmission towers.
Network Setup
Based on the above site merits, the wireless service provider will find the best possible cell site configuration, while providing good coverage to the area with a minimal number of coverage holes. The wireless service provider will also try to keep cell site construction and leasing costs low.
Once a configuration has been determined then construction of the network may begin. Often the wireless provider will not build the sites, but rather will contract out site building to one or more firms that specifically build and maintain radio transmission towers. In some cases, several contracts will be issued for running T1 lines, erecting monopoles, installing antennae racks and antennae, building secure compounds, placing foliage around ground compounds, etc.
Figures 8a-e. Various cell installation types.
Some of the site installations used by wireless providers may include:
Hydro towers. Large grey metal towers holding high-voltage lines. Usually a square rack is placed at the top of the tower (Figure 8c).
Environmental monopoles. Large poles painted green to resemble trees. Usually hold high-voltage lines. A rack may be placed above or below the hydro lines.
Monopoles. Large poles painted grey, beige, green, or orange/white, that are exclusively for the use of cellular transmission equipment. Round racks may hold cells out from the monopole or the cells may be directly attached to the monopole (Figure 7).
Microwave or radar towers. Large towers filled with microwaves and other transmission equipment (Figure 8b).
Chimney racks. Round racks attached to an industrial chimney to hold cells.
Fancy cement poles. Custom designed poles to hold cellular transmission equipment while looking like art.
Fake trees. Artificial trees that hide the cellular transmission equipment in the foliage at the top (Figure 8d). Not generally found in Canada.
Real trees. Cells are mounted to sides of real trees (Figure 8e). Not generally found in Canada.
Building flat mounts. Cells are hung over the side of the top of a building.
Building elevator shaft mounts. Cells are mounted on the elevator shaft. This mounting may create a shadow of coverage around the building (Figure 8a).
Building pole mounts. Cells are stuck on little poles attached to the top edge of a building.
Building tower mounts. A rack or tower is placed on top of the building to increase the cell height.
Lamp standards and flagpoles. Cells are placed on top and blend in with the supporting object (usually micro cells)
Intentionally hidden sites. Cells that are well hidden by camouflage or other means. Usually due to public concerns over the unattractiveness of cell sites.
Ceilings. Cells are suspended from the ceiling (pico cells)
Case Study: The old Clearnet PCS (now Telus Mobility) network in Victoria, BC
In the fall of 1998 Clearnet Communications set up their digital network in Victoria, British Columbia. Prior to the launch of their digital network, Victoria Clearnet clients were able to purchase handsets that would roam on the Rogers analog network.
These are some of the conditions, problems, and features that Clearnet PCS, as well as other wireless service providers, had to deal with when installing their wireless networks in Victoria:
Mountainous terrain. Victoria is a relatively hilly city when compared to other major Canadian cities. Hills give rise to coverage problems in terms of holes and shadow areas. Victoria has several distinct ridges that are higher than most cell sites.
Hills. Those hills that give coverage problems can also be used to mount cell towers to cover areas on all sides of the ridges.
Water. Victoria borders the ocean on the south, west, and north sides. Water is an ideal terrain that carries radio signals a great distance.
Lack of tall buildings. When compared to other major Canadian cities, Victoria has relatively few tall buildings to mount cells outside of the downtown core.
Residents. Victoria residents are very resistant to large-city development, be it a Home Depot, Costco, condo developments, or cell towers. Microcell has had a very difficult time establishing towers due to residential complaints in Victoria. Both Rogers and Microcell have had more than one tower proposal shot down by residents.
Clearnet PCS was the last of the four wireless services providers to establish their digital services in Victoria in December 1998. Microcell established a limited network in May 1998 and slowly added sites to increase coverage area. At present, Clearnet PCS provides the most limited digital network in Victoria, however, customers may roam on Rogers' analog network without incurring additional airtime charges in their monthly statements. Both Telus Mobility and Rogers operate their digital networks using the 800 MHz band in Victoria. As of Spring 2000 both Telus and Rogers have started to install their 1900 MHz cells in the Victoria area.
Footprint
Let's have a look at Clearnet's PCS coverage footprint for the Victoria area as of October '99 (Figure 9). This map shows all of the Clearnet PCS cell tower locations in Victoria and onlines the coverage area of each tower's cells. Each coverage area has not been extended into adjacent cells to keep the map simple.
Numbers within each cell's coverage area indicate the Clearnet tower number, based on CDMA PN offset values. If you would like to know more about how these numbers are determined, have a look at the Field Debug section in my FAQ's. Clearnet only operates towers with two or more antennae in the Victoria area. Most of the towers have three sets of antennae or cells that cover an approximate range of 120 degrees from the tower. If you'd like to see more detailed maps showing the separations on the towers, have a look at the Capital Regional District maps available on this site.
Number of active cells and general coverage
In total Clearnet PCS has 15 active cells in the Victoria region. This is a limited number when compared to other urban centres that have many more cells for a lower per capita population. Part of the reason behind this is that many of the sites have been placed a fair distance from the water and as such, no adjacent sites have been required to handoff calls. In addition, Clearnet has two excellent coverage sites that take advantage of the hilly terrain of Victoria. On the flip side of this argument, many of the sites adjacent to the water have created regions that lack coverage around the shoreline due to ridges adjacent to the water (note the four distinct holes on the southeast side of the map).
Placement and leasing issues
All tower sites in Victoria are leased or sub-leased. Of the 15 towers, 2 are on residential property, 1 on agricultural property, 3 on commercial property (includes apartment buildings), 3 on limited or non-commercial property (care homes, churches, raceways), and 6 on public property (hydro towers, university, municipality, provincial, or federally owned land).
Of these sites, Microcell Connexions sub-leases space to Clearnet on three locations. Besides cost-cutting issues, Clearnet may have chosen to sub-lease space on Microcell monopoles to minimize residential complaints over the establishment of more towers.
Figure 9. Clearnet PCS coverage footprint for Victoria, BC. Cell tower locations, coverage areas, and identification numbers have been marked.
Conclusions
Microcell Connexions has been working very hard to establish their 1900 MHz digital networks across Canada. Both Telus and Rogers have well-established analog and digital (800 MHz) cellular networks across British Columbia, and are starting to build new 1900 MHz networks. These new networks will likely use many of their existing 800 MHz cell sites, but several new tower sites will need to be added. Both Telus and Rogers will face some problems when establishing these new sites, especially in Victoria, where residents have turned down several proposals for new cell towers already.
Everyone wants to use wireless phones, but few people want the towers in their neighbourhood. Residents of Cadboro Bay complained to Microcell that their Fido phones didn't work in their neighbourhood. These are the same residents that shot down several Microcell proposals to establish a tower in the neighbourhood. To try and bring coverage to this area without establishing a tower, Microcell opted to place a tower on Vantreight Island to the east (shared with Telus and Rogers), yet this did not really solve the coverage issues in Cadboro Bay. At the moment Microcell's hands are tied.
Figure 10. The inside workings of a cell tower site, as depicted on 'The Simpsons'.
As more and more of us make wireless phones part of our daily life, many of these coverage problems will be solved by developments in new cell tower equipment and the placement of micro and pico cells in areas where residents are concerned over large cell towers. Wireless providers also need to work together in building monopoles and other tower types in areas lacking existing buildings or towers to hold their equipment. Cell towers may look ugly, but many people would rather see one tower instead of four.
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