Jun 29, 2023

Wireless on the Edge: Connecting Hard-to-Serve Areas

Future-facing broadband service is often equated with Fiber to the Home, but in rural, remote, and urban areas with special challenges, wireless service can be the only realistic option for backbone access at the edge. Part of the challenge is deciding which technology solution best suits the geography, landscape, structures, and population distribution of the area under consideration, as three California school districts and their carrier partners determined.

Rural and Urban Challenges to Edge Networks

Constructing fiber routes over long distances can be prohibitively expensive, and remote areas can also be environmentally sensitive and come with permitting challenges, particularly when construction must take place away from rights of way. In these cases, tower construction may be much easier and less costly than miles of fiber route construction.

Urban areas are not immune from these considerations. High construction costs are commonplace in heavily populated areas, and many urban areas have historical districts, limits on construction or aerial installations, or restoration guidelines to contend with. In all cases, these obstacles can result in affordability issues when providers pass their costs along to a small or economically challenged group of potential customers.

In cases where wireless options may be the only solution, they must be assessed to determine which is best. An urban environment may benefit from an “Internet at home” product that delivers service via the cellular network, and with the advent of 5G, this can result in a higher bandwidth of 100 Mbps or more to the home. Remote areas with spotty cell coverage may instead choose a point-to-point installation that uses a licensed or unlicensed frequency band. (Unlicensed bands sometimes overlap with common appliances, such as garage door openers, and both cases require study, including on power levels, to avoid interference with already existing wireless applications.)

Challenges to Fiber in Rented, Manufactured, or Older Dwellings

As home ownership costs continue to climb throughout the US, many families in all areas may find themselves living for longer periods in rented apartments, houses, and multi-tenant dwellings or mobile home parks. Costs for fiber installations can be prohibitive in these types of homes, and landlords may not be willing to make the investment. In these cases, wireless installations may be the only choices available for tenants or mobile home owners in search of broadband connectivity.

In addition, any older structures may lack necessary infrastructure for fiber installations, whether owned homes or multi-tenant complexes, and some homeowners in any case simply may not wish to make the structural changes necessary. In these and the situations previously described, wireless technologies, be they point-to-multipoint or mesh, can be the preferred solution.

High or Low Frequency: Bandwidth v. Penetration

Penetration and bandwidth also vary depending on the chosen frequency band for wireless access. Lower frequencies can transmit much farther than higher ones and can penetrate and travel around obstacles such as buildings and trees. However, bandwidth is lower; for example, the 900 MHz band that public safety agencies typically use to broadcast can support voice and text but not images or videoconferencing.

In contrast, high-frequency signals can carry more data but do not travel nearly as far as lower-frequency signals and do not penetrate obstacles such as buildings and trees. In addition, while high winds and swaying towers can interfere with performance at all frequencies, rain can interfere with higher frequencies. This phenomenon, known as “rain fade,” occurs when the size of water droplets becomes comparable to the wavelength of the signal. In both cases, severe weather can cause antennas to ice over, requiring costly and even dangerous maintenance to restore service.

To complicate matters further, the ubiquity of fiber in the better-served areas of the country drives the performance requirements of many common applications. In other words, telework, telehealth, and remote education have become almost synonymous with videoconferencing supported by ample reliable bandwidth, so if a wireless edge network cannot accommodate these applications, its usefulness to potential customers is limited.

Leasing, Permitting, and Power

Furthermore, the tower and the ground on which a tower stands are sometimes owned or managed by two different entities, complicating the leasing issue. In some cases, installation approval cannot be obtained until all required regulatory permits are acquired, resulting in extended approval time frames.

If no suitable tower exists where needed, one may need to be built, and plans must be shared with and approved by the owner of the land on which the tower will stand. Sometimes more than one tower—more than one “hop”—is required for very challenging areas. This was the situation in northern California, where the Hoopa Valley Tribe required five wireless installations to provide backhaul to their location.

Especially in areas in which little to no commercial power is available, backup solar- or diesel-powered generators are needed. More renewable energy options are becoming available, but diesel generators are still common. For those located in mountain ranges, refueling can involve periodic helicopter visits.

Wireless Case Studies in Three California School Districts

Three California case studies from a report by the Schools, Health & Libraries Broadband Coalition (SHLB) and the Open Technology Institute, “The To and Through Opportunity: Case Studies of School and Community Networks Able to Close the Homework Gap for Good,” are particularly useful to illustrate how performance, population, geography, and infrastructure can be balanced in order to provide wireless service at the network edge.

Even prior to the COVID-19 pandemic, school districts were investigating ways to enable themselves and their students to take advantage of online learning opportunities despite the lack of reliable broadband service to homes in un-and underserved areas. Many school districts around the country turned to wireless technologies and among them were the East Side Union High School District and the Fontana and Val Verde Unified School Districts in California.

The East Side Union High School District worked with the city of San Jose and third-party integrator SmartWave on a mesh Wi-Fi solution in the unlicensed 2.4 GHz and 5 GHz frequencies – excellent for more densely built and populated areas – where access points were installed on city light and traffic signal poles and could use the city electrical power that the poles provided. Hundreds of access points were needed to provide adequate, reliable coverage, although each was comparatively inexpensive. Backhaul was provided via existing city fiber where possible, and 24 GHz and 60 GHz millimeter-wave technology was able to provide it where fiber was unavailable.

Homes in the Fontana Unified School District were less concentrated around the district’s center, which also made wireless the solution of choice. The district chose to work with Crown Castle Fiber on a solution using Citizens Broadband Radio Spectrum (CBRS) technology operating between 3.5-3.7 GHz and offering excellent propagation and bandwidth. Over 300 access points were needed to cover the district once various permitting hurdles were cleared to install them and access city-owned power.

In the Val Verde Unified School District, meshed Wi-Fi was not ideal, and their incumbent ISPs lacked the extra capacity to serve their students. After the implementation of a pilot project for a high school located in a valley, which revealed that the signal strength was affected, sometimes profoundly, by the valley topography, they chose a hybrid approach with GeoLinks using CBRS for flatter areas and Wi-Fi for hilly ones.

In these and other cases, balancing geography, population density, and available infrastructure to determine which wireless edge network solution works best for a given area can be daunting, but solutions do exist, and knowledge of the various trade-offs help make the challenge more manageable.

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