• Cell on Wings, an AT&T product, can help fill communication gaps in sparsely populated regions though they are currently only used for AT&T customers.
  • Loons, an Alphabet Inc. product, can augment terrestrial cell services after a storm in urban and mountainous regions.
  • To ensure their function, partnerships will need to be established with local ground stations.

According to the Federal Communications Commission (FCC), 95% of all cell towers were out of service after Hurricane Maria.[1] It took about half a year to get almost all cell towers fully functional. Without functioning telecommunication infrastructure, Puerto Ricans were unable to contact family members, call emergency officials (i.e., police officers, firefighters, and EMS), or gather information about the state of the island. New technologies such as Cell on Wings (COW) and Loons can help provide temporary connectivity during the recovery process.

Figure 1: (Left) For most counties in Puerto Rico, more than 81% of their cell towers were out of service right after Hurricane Maria made landfall on September 20, 2017. (Right) Six months later, not all cell towers were restored. [1]
Figure 2: AT&T flying Cell on Wings (COW). [2]

AT&T: Cell on Wings*

In the aftermath of Hurricane Maria, AT&T deployed a new technology called Cell on Wings (COWs), which are drones equipped with cell towers to provide temporary cell service to AT&T customers while communication lines were being repaired. [1] These COWs fly 200 feet off the ground and can withstand heavy rain, 50-mph winds, and extreme temperatures. They can “see through smoke, tree covers, and other obstacles.” [2] Powered by a truck of solar panels, a COW tethered to a router can provide LTE data, voice, and text services within a three-mile radius. [3] Given that the area of the solar panels on a truck used to power a COW is approximately 5 m2 and that the average amount of direct solar radiation received by Puerto Rico during hurricane season is an estimated 12kWh/m2 per day, [4] the solar panels can capture 625 W in a day. [6] Assuming that the COWs require about 60 W/hr to run, it would not have enough energy to run for 24 hrs. Therefore, we suggest that multiple trucks of solar panels be used to power the COWs and store enough power in batteries for night time operation.

Given that Puerto Rico is 3,515 mi2, one hundred COWs would be needed to provide cell service to the entire island. Because the cost of the technology and the ability to handle high data traffic is unknown, it is best to limit the use of COWs to rural areas with low population density. That way it can be ensured that most data placed through COWs is pushed into the AT&T server. The drones can also be used by first responders because they can be easily transported from one place to another; they can also follow behind emergency vehicles, ensuring service to first responders at all times.

Though much is unknown about people’s experience using it, COWs can still be implemented to provide communities with connectivity after a storm. It is also understandable that the use of drones poses questions about the safety and privacy of Puerto Ricans. However, it can be arranged that while a COW is operational it carries no cameras. Also, most of the time, the COWs are hovering in one place. For the safety and integrity of the technology, however, people could be hired by AT&T to monitor the COW while it is operational. Also, AT&T branches in Puerto Rico could train local employees to allow them to become familiar with using drone technology. Hence, many of the privacy and safety concerns can be overcome with modifications in the technology and implementation process; therefore, those concerns should not stand in the way of using COWs.  

A limitation to implementing the AT&T Cell on Wings is that they are currently available to AT&T customers. However, in the future, other cell service providers may produce a similar system or partner with new technologies like Loons to augment their current system.

Alphabet Inc.: Project Loon**

©Alphabet Inc.
Figure 3: A Loon launched in Winnemucca, Nevada after Hurricane Maria. [7]

Loons could also be used to provide connectivity after a hurricane. They are an experimental project started by Alphabet Inc. in 2011. Similar to COWs, Loons were used after Maria to provide internet connection to more than 100,000 Puerto Ricans. [8] The duration and cost of the Loons operation is unknown. A Loon is made up of a balloon, an antenna, solar panels, and a flight capsule. The antenna allows the loon to transmit connectivity signals from local internet service providers on the ground to LTE phones. The balloon is made out of ultrathin polyethylene film, and it allows the Loon to travel 20 km into the stratosphere. [9] Turbulent weather and mountain ranges are contained below the stratosphere as are wildlife and planes. In the stratosphere, wind speeds are generally from 10-20 meters per second in the east and west directions, allowing the balloon to move horizontally. The vertical motion of the balloon is controlled by an on-board pump. The balloon can also withstand low temperatures. [10] Lastly, in the stratosphere, the solar panels can generate up to 100 watts which is more than the power necessary to move the balloon during the day. [11] The excess power is stored in a battery for use during the night. 

The Loon uses predictive models and machine learning algorithms to map and analyze wind patterns and to choose an optimal flight pattern. However, Loons can also be manually controlled to remain over a region to ensure connectivity to most users, especially those in need (“X-Loon”). The Loons work by relaying cell signals from ground stations to LTE enabled phones, which means they need to work in conjunction with a cell phone service provider. During Maria, Alphabet partnered with T-Mobile and AT&T. [7] Also, the balloon uses the 900 MHz frequency band, which is currently supported by many cell towers and cellular devices. [10] Therefore, the loons are compatible for use with the current system. 

Figure 4: Locations of some cell towers in Puerto Rico. The figure depicts the location of Claro’s (a cell phone service provider) cell towers in Puerto Rico which are disproportionately in urban areas. [12]

Surviving cell towers after a hurricane can send a signal to a balloon, which can bounce signals to other balloons in the region. [13] Thus, a handful of towers can provide service to the whole island, which is great for Puerto Rico given that they have a disproportionate amount of towers in the northeast compared to the rest of the island, as seen in figure 4. A single balloon can cover an area of about 1,212 mi2 — the size of Rhode Island. [7] Given that Puerto Rico is about 3,515 mi2, about 3 balloons can ideally cover all of the island. However, accounting for wind patterns, about six to eight balloons, as shown in fig. 5, are needed to cover the entire island.

Figure 5: Connectivity Range of Loons in Puerto Rico. The figure shows the connectivity range of Loons over Puerto Rico after Hurricane Maria. [13]

The Loons can potentially provide cell service once a storm has mostly subsided given functional cell towers. They can be launched before the storm: once meteorologists predict the onset of a tropical storm, the auto launcher can launch one balloon every thirty minutes. [14] There is a Loon launching site in Puerto Rico that was damaged during the storm, but given that it is repaired, the balloons would be launched right over the island. Additionally, there is a launching site in Winnemucca, Nevada where the Loons for Puerto Rico after Hurricane Maria were launched. If the launcher in Puerto Rico is damaged, the Winnemucca launcher can be used to release Loons towards Puerto Rico. Of course, once the launcher in Puerto Rico is fixed, it needs to be maintained so that it does not get damaged again during a storm. Once the Loons are above Puerto Rico, they can remain up for about one hundred days, much longer than the average duration of a storm. [14] Communications could restart quickly, allowing people to connect to first responders and family members. However, the 2017 FCC report after Hurricane Maria showed that it took about six months to repair the cell towers. So it’s possible to release more balloons as the older balloons are brought down to maintain a constant internet service.   

Loons are unable to work without ground stations to send connectivity signals. Hence, we propose that local cell service providers sign deals with Loon LLC., a subsidiary of Alphabet Inc. to augment their terrestrial cell service. Loons becoming a part of the local cell services would give Puerto Ricans not only more insight into the technology implemented and but also jobs to maintain and run these operations. Loon LLC. would be favorable to this partnership because it would expand the market of Loons and help achieve their goal of bringing internet to inaccessible places. Recently, Loon LLC. signed a deal with Telkom Kenya to provide internet service to inaccessible places in Kenya, and one of the main parts of the deal was to provide quality and affordable internet. [15] If a similar deal was to take place between local telecommunication companies in Puerto Rico and Loon LLC., it would be possible to provide connectivity right after a hurricane.

*Copyrighted by AT&T Inc.

**Copyrighted by Alphabet Inc.