Social Distancing and the Contact Tracing Solution

August 13, 2020 by Giandri Machado

Social Distancing is a public health procedure or a group of procedures oriented by health authorities (WHO, CDC, ACL, HHS and more) to prevent the spread of contagious diseases that can be transmitted by contact or air. Sometimes also recognized as Physical Distancing Intervention, it states the distance two individuals should be from one another during this social distancing period. In one-on-one proximity, this is an easy regulation to follow. Nonetheless, each time we bring a new individual to this same space, this preventative procedure becomes more complicated, and depending on the metric recommended for this distance, sometimes it is not possible to have more than a certain number of people in a defined area. Further, it takes into account the unknown history of an individual’s behavior and the previous route of that individual who may become a risk to another one.

However, it is different within a household, where all individuals may track each other’s routes and behavior; after a certain period, this trace may becomes unique for all individuals in the household. Another factor that may impact social distancing is the protection gears, called personal protective equipment (PPE), where specified protection suites are required according to how contagious the disease is. Due to this isolation, these individuals become null as points of interest within the social distancing model.

A Mathematical Model

Yes, all of the above is configured by a mathematical distancing (and proximity) model that, like any mathematical model, will work properly when knowing the universe considered, such as a stadium, a mall, a hospital, a supermarket, a sidewalk, a public service facility, an airport, a manufacturing plant, an open construction site, or an office building with a narrow hall and corridors. Since those areas are not independent, all studies need to correlate them. Each universe or community has its natural and/or deployed barriers of mobility and will impact, directly and intensively, this mathematical model. 


6-feet distancing and tracing illustration Figure 1: 6-feet distancing and tracing illustration

Social distancing became a real concern amidst the arrival of COVID-19, wherein a few days, people from all over the world received orders that they needed to stay home or six feet away from any individual they did not know. Further, our doctors needed to use PPE, almost with full-body sealing. The average citizen, on the other hands, was tasked with wearing face masks when in a public domain area. As a heated point of discussion, our mathematical model also has a polarizing variable to be considered, since it was speculated that by using masks, an individual would be less likely to either contact or transmit the disease.

More and More Factors

If you wash your hands for twenty seconds, this risk of contamination is likely eliminated; if you use sanitizer, you will also probably eliminate risk. Now, the model is getting complex. The worst context: depending on the individual’s health condition, unknown factors can make contracting COVID-19 fatal, so these individuals should receive even more elaborate social distancing protection. Meanwhile, some individuals who transmit the disease are not even aware that they have it. Thus, some actions could suppress and weaken the probabilities of contracting COVID-19 while others could strengthen it.

Professional Social Distancing. Companies Need to Come Back to Work…

Amidst the pandemic wave(s) of COVID-19, companies became eager to bring back the flow of business. Yet, social distancing demanded authorities to issue a lockdown, or a “stay-home order.” In a few hours, busy offices became empty and the home office became a family shelter while simultaneously functioning as a professional office. Through modern virtual and cloud technologies, many home offices were a suitable replacement for the regular office. However, after this abrupt halt, entities like manufacturing plants with production lines needed to establish a fade-in production program through certain hygienic individual protections (masks, sanitizers, etc.) and team procedures (distancing). The fade-in program may respect physical and/or time distancing to avoid risks, promoting a controlled personnel distribution and health control.

new mobility flow Fig. 2: An office manager may define partial personnel back-to-office based on priorities of scopes, and can even define mobility protocols to avoid agglomerations
Worksites can establish shifts timely Figure 3. Worksites can establish shifts timely synchronized to bring back the production at a certain production rate, keeping the health conditions

All of these procedures could not avoid the fact that certain production plants started looking into tracing individuals (in indoor and outdoor work sites) within the production line, in the warehouse, or even across the logistic chain in order to avoid contamination and also serve as a guide for best practices and performance.

Feasibility: The Search for Technologies

Feasibility The Search for Technologies

These inquiries from several companies had one single answer. We have been excellently tracking and tracing our fleet, our pallets, our products, and all of our mobility assets. We could even be aware of where our professionals were through their smartphones. What about distributing those wearable tracking devices to all employees? This way we could analyze positions, distances, and even routes and be alerted, in real-time, to bad behavior or risky routes. We could also analyze the history of this mobility model and see if it could be recalculated or optimized to avoid the risk of contagion.
It is believed that most organizations already have complete or partial assets management with inventory control, pallet placement tracking, shipment verification, and even personnel access control. The point now is social distancing and tracing.
But COVID-19 social distancing says to stay six feet apart. At this point, another question appears, asking about the positional accuracy that those devices are able to report on, including behaviors, routes, and all mobility variables needed for a correct analysis of a real-time alert or guidance, or an in-batch informed decision-making process, based on all factors and considerations brought up previously.

Existing Technologies

Technologies for social distancing Figure 4. Technologies for Social Distancing Tracing

By doing some market research, wireless technologies were found and appraised concerning how they can be used for people tracking, tracing, and orientation.

The old friends GPS , RFID , Wi-Fi , Bluetooth , and UWB are the most prevalent. Each one brings different factors of feasibility, mobility, route track and tracing, and obviously, pricing. Naturally, wired technologies are the basement of several communication architectures, but cannot be considered for people tracking.

Communication Range of most Common Technologies available for Social Distancing Tracing solution Figure 5. Communication Range of most Common Technologies available for Social Distancing Tracing solution

Besides the GPS, all lined technologies are radio frequency-based and will track the required distance between the transmitter and receiver as a key parameter, which will be called range.

GPS: GPS is comprised of a satellite-based system that is related to each receiver. With GPS, a group of people can only be analyzed outdoors, but faces restrictions in certain areas since some urban or natural barriers could impact the accuracy of the mathematical model. Additionally, the accuracy of the light GPS receivers embedded in our smartphone, for example, is from 19 to 65 feet (roughly three to six meters, or ten meters for old phones still on the market), which would not conform to the accuracy requirements demanded by social distancing parameters. An accurate GPS receiver is substantially bigger, too impractical to wear, and very expensive, thus making it infeasible for most applications. The smartphone-like GPS can be part of the full solution, but it is not the right one for social distancing.
RFID: As a local receiver-based system, RFID can be used outdoors and indoors. It has been widely used to track the mobility of assets, such as packages, pallets, products, and even people (through our badges, for example). The tracking accuracy can be from one inch to three feet, depending on the model (active/passive), the architecture of the readers, and procedures of usage. RFID should remain as one of the main possibilities, with the awareness that the range is short. Hence, RFID is a considerable technology for the measurement of social distancing, but would demand a massive, dense, deployment of devices within the desired area. As such, it is not a likely technology that can be used on scale and in real-time.
WiFi: Widely used for the internet network, the WiFi concept and its employed technology bring back the problem of accuracy, where the best measurement offered for a position is approximately the same as the GPS, from 14 to 65 feet ( roughly 4 to 20 meters). As such, WiFi is not a winning solution when it comes to individual tracking and tracking.
Bluetooth: This technology is widely used due to the relation between accuracy and range. It has the most potential as it has been on the market for a while, embedded in our smartphone, earphones, wearables and several other devices in our home and our offices. As anticipated, the accuracy submits to the 6 feet program requirements of the COVID-19 distancing order, and when scaled within its range, brings forth a sustainable solution that can be used for distancing and mobility measurements. When making a quick decision about employing the right technology, bluetooth is the best seller today, even more so when considering its new generations where the range has been improved.
UWB: Considered the youngest of the group, although its regulation was established around 20 years ago, UWB’s first market appearance occurred in 2013. Only last year did it become a promising solution for mobile applications since it can scan a long range with the highest accuracy (inches|roughly 10 centimeters) and with sustainable scalability, fighting directly with bluetooth inside the same environment employment. As a result, it is definitively the most promising one. In fact, Apple® and Samsung® have announced their new devices are already bringing UWB technology on board.

Several other parameters not mentioned in the above summaries can be seen in the following table and should be considered during the design of the adequate architecture.

Stefanini Ongoing Research for Social Distancing Technologies Figure 6. Stefanini's Ongoing Research for Social Distancing Technologies

Power Consumption and Data Flow

Wi-Fi, Bluetooth, and UWB are wireless technologies that were born and oriented to digital data transmission. The related power consumption challenge in the design of a social distancing tracing solution may also be related to in-scale, timely energy consumption. The following chart provides a vision of the energy usage for a flow of 10GBytes of data, and their frequency spectrum, where considering the individual autonomy based on the replaceable battery, it is recognized that UWB is a good choice for wearables and other tags that are distributed within the mobile part of the solution.

Additionally, due to the nature of the technologies, its spectrum, and emitted power signal, UWB may allow for a more reliable connection even in a noisy environment.


As in any production environment, one main point is raised during the design of a distancing solution, where all pieces (people, vehicles, machines, cargo, etc.) of the puzzle need to be monitored: This main point is the worker’s individuality and privacy, which are key factors of employability. Thus, the design of this full tracking system needs to consider the regulations and ethics components that promote health comfortability to employees, the company’s principles and performance, and respect the employees’ privacy.

The Social Distancing Solution

Reading all of the above, we can recognize that the solution needs to follow a mathematical model that will demand the most traditional computing capabilities and layers existing today. Those layers can be selected as a simple analytic model understanding real-time positions, alerting, guiding personnel and assets mobilization, and promoting a certain level of the informed decision process. The designed solution can also demand a higher level of computing layers like deep analytics, machine learning, and artificial intelligence.
The complexity of the selected layers will impact the complexity of the deployment, promoting a high level of confidence in the decision-making process. Independently, those selections need to be made based on the critical level of the operation, the complex priorities of the real-world environment, and the number of individuals playing different roles in that environment. Different work scopes may receive priorities over others in a mobility model.

When it comes to selecting the tracking and tracing devices (wearable or handled), we can assert that there is no silver bullet. Combining all of them can fill out the completeness demanded by an operation that may have indoor and outdoor sites, including different contexts, distribution of assets, and personnel.

After the Vaccine

The right solution is not a set of technologies that will be disregarded after the arrival of the COVID-19 vaccine. The employment of a mobility solution is also about performance studies and informed decision-making, where it can forecast a company’s preparedness for any future context that requires personnel distribution management, efficiency gains, cost reduction, and performance triggering, bringing to the production lines a high-level of management intelligence.

[1] GPS: The Global Positioning System (GPS), originally NAVSTAR GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. Obstacles such as mountains and buildings block the relatively weak GPS signals. The GPS does not require the user to transmit any data, and it operates independently of any telephonic or internet reception, though these technologies can enhance the usefulness of the GPS positioning information. The GPS provides critical positioning capabilities to military, civil, and commercial users around the world. The United States government created the system, maintains it, and makes it freely accessible to anyone with a GPS receiver.

[1] Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID tag consists of a tiny radio transponder; a radio receiver and transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an identifying inventory number, back to the reader. This number can be used to inventory goods. There are two types. Passive tags are powered by energy from the RFID reader's interrogating radio waves. Active tags are powered by a battery and thus can be read at a greater range from the RFID reader; up to hundreds of meters. Unlike a barcode, the tag doesn't need to be within the line of sight of the reader, so it may be embedded in the tracked object. RFID is one method of automatic identification and data capture (AIDC). RFID tags are used in many industries. For example, an RFID tag attached to an automobile during production can be used to track its progress through the assembly line; RFID-tagged pharmaceuticals can be tracked through warehouses; and implanting RFID microchips in livestock and pets enables positive identification of animals.

[1] Wi-Fi, a shortened form of "Wireless Fidelity",  is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access. Wi‑Fi is a trademark of the non-profit Wi-Fi Alliance, which restricts the use of the term Wi-Fi Certified to products that successfully complete interoperability certification testing. As of 2010, the Wi-Fi Alliance consisted of more than 375 companies from around the world. As of 2009, Wi-Fi-integrated circuit chips shipped approximately 580 million units yearly.[6][needs update] Devices that can use Wi-Fi technologies include desktops and laptops, smartphones and tablets, smart TVs, printers, digital audio players, digital cameras, cars, and drones. Wi-Fi uses multiple parts of the IEEE 802 protocol family and is designed to interwork seamlessly with its wired sibling Ethernet. Compatible devices can network through wireless access points to each other as well as to wired devices and the Internet. The different versions of Wi-Fi are specified by various IEEE 802.11 protocol standards, with the different radio technologies determining radio bands, and the maximum ranges, and speeds that may be achieved. Wi-Fi most commonly uses the 2.4 gigahertz (120 mm) UHF and 5 gigahertz (60 mm) SHF ISM radio bands; these bands are subdivided into multiple channels. Channels can be shared between networks but only one transmitter can locally transmit on a channel at any moment in time.


[1] Bluetooth is a wireless technology standard used for exchanging data between fixed and mobile devices over short distances using short-wavelength UHF radio waves in the industrial, scientific and medical radio bands, from 2.402 GHz to 2.480 GHz, and building personal area networks (PANs). It was originally conceived as a wireless alternative to RS-232 data cables. Bluetooth is managed by the Bluetooth Special Interest Group (SIG), which has more than 35,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. The IEEE standardized Bluetooth as IEEE 802.15.1, but no longer maintains the standard. The Bluetooth SIG oversees development of the specification, manages the qualification program, and protects the trademarks. A manufacturer must meet Bluetooth SIG standards to market it as a Bluetooth device. A network of patents apply to the technology, which are licensed to individual qualifying devices. As of 2009, Bluetooth integrated circuit chips ship approximately 920 million units annually.

The Bluetooth versions:

bluetooth variations

[1] Ultra-wideband (also known as UWB, ultra wideband, ultra-wide band and ultraband) is a radio technology that can use a very low energy level for short-range, high-bandwidth communications over a large portion of the radio spectrum. UWB has traditional applications in non-cooperative radar imaging. Most recent applications target sensor data collection, precision locating and tracking applications.As of September 2019, UWB support has started to appear in high-end smartphones. Ultra-wideband is a technology for transmitting information spread over a large bandwidth (>500 MHz); this should, in theory and under the right circumstances, be able to share spectrum with other users. Regulatory settings by the Federal Communications Commission (FCC) in the United States intend to provide an efficient use of radio bandwidth while enabling high-data-rate personal area network (PAN) wireless connectivity; longer-range, low-data-rate applications; and radar and imaging systems.


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