Internet of Things Communications Landscape Background and purpose The Internet of Things (IoT) is an emerging field that encompasses a wide range of devices connected to each other, and/or the internet to provide services such as real-time data collection and analytics. PATH is specifically looking into IoT for potentially monitoring cold chain equipment (CCE) inventories via automated data recording of equipment performance. Performance metrics may include vaccine compartment temperature, humidity, power availability, and door opening. A key component of IoT is wireless communications for transferring data between sensors and monitoring systems. This is especially important for health care facilities without access to traditional internet service providers and requires data transfer to another location with an internet connection. This landscape documents wireless data communication technologies and their performance characteristics, such as transmission range, network topology, licensing, and power consumption. Most of these technologies are protocols for transmitting data via modulated radio signal. The most commonplace of these include Wi-Fi, Bluetooth, and cellular. Satellite systems were not explored due to their high cost. Most IoT systems will use at least one wireless network communication technology at some point in the system. Documenting the specifications of these technologies is useful to us for several reasons: • It aids in conversations when people have varying levels of knowledge of wireless network communications. • It is helpful for evaluating data transmission methods used by IoT systems. • It can guide our search for appropriate IoT systems to support CCE monitoring. • It could reveal gaps in existing CCE monitoring technologies in low- and middle-income countries (LMIC)—prompting development of new technology. Basic properties of radio communications Most radio communications technologies for data transmission are reliant on “line-of-sight propagation” between sender and receiver. As such, any objects (geography, buildings, traffic) that block the direct path between sender and receiver will impair signal quality and transmission range. In addition, maximum transmission range depends on the square root of antenna height above the ground due to the curvature of the earth. 3.57 × There are two main exceptions to thisℎ (both of which≈ are� typicallyℎℎ for audio only): • Low-frequency radio below 3 MHz (e.g., AM radio) can follow the contour of the earth’s surface as ground waves. PATH is a global organization that works to accelerate health equity by bringing together public institutions, businesses, Mailing Address Date Published social enterprises, and investors to solve the world’s most pressing health challenges. With expertise in science, health, PO Box 900922 December 2019 economics, technology, advocacy, and dozens of other specialties, PATH develops and scales solutions—including Seattle, WA 98109 USA vaccines, drugs, devices, diagnostics, and innovative approaches to strengthening health systems worldwide. Street Address path.org 2201 Westlake Avenue Suite 200 Seattle, WA 98121 USA • Shortwave radio between approximately 1.7 and 30 MHz can reflect off the earth’s ionosphere, potentially allowing for global reach. Methodology We took the steps below to complete this landscape: 1. We started with Wikipedia searches for different wireless communications, such as https://en.wikipedia.org/wiki/Comparison_of_wireless_data_standards. o We looked at related topics and comparison tables to find additional technologies to research. 2. As we encountered network communication technologies through our research, we added them as a new row in the table. 3. We performed research to fill out all unfilled boxes in the table. o We did not focus on finding the most reputable sources. If we found information on a website that looked questionable, we checked it against one or two other sources. This is meant to be a rough guide, not a rigorous technical reference. o If a piece of data was not available after our search, we recorded “not found.” o For technologies that only defined higher levels of the network (i.e., software) or were not for data transmission (analog radio), we used “N/A” for any physical layer information that is not applicable. See Annex for information on network theory. o If we found several values for the same field, we kept the seemingly more accurate value. If that could not be determined, the value with the best performance was picked. For example, if maximum range is listed as 50 m in one source and 100 m in another, 100 m was recorded. The recorded values in the table represent a best-case scenario, and real-world performance will be lower depending on the conditions of use. o If references to other technologies were found during this research, we added them to the table for future evaluation. 4. We organized the technology into a parent group based on transmission distance, application, or both. It was sometimes difficult to find reliable specifications on these technologies. For example, in a case where we wanted to find the maximum theoretical transmission distance given a certain transmission power, what we found instead was typical transmission distance subject to device power regulations, radio space regulations, and desired data bitrate. Antenna design also played into this, as well as height above the ground. Basically, this convoluted information made it hard to make one-to-one comparisons between technologies. However, this direct comparison was not the purpose of the landscape: the purpose was to identify a list of all possible communication strategies as a jumping off point for further evaluation. Table population Column definitions Term Definition ID Identifying number for the technology. Assigned numerically at the end of table population. Title Name/title of the technology. Some may have several names and/or acronyms. Standard(s) Standards, specifications, or working groups related to the technology. Physical layer/Air interface • Refer to Network theory supplemental info in the Annex for more information. Physical layers may be defined by a standard. 2 • Technologies may have several physical layers. Modulation method • Method used to modify the radio frequency for carrying information. • Technologies may have several modulation methods. Frequency range (Europe) • Center frequency of the band(s) used. • Technologies may use several frequency bands. • Frequencies vary from country to country. For the purposes of this table, only European frequency bands were included. • Industrial, scientific, and medical (ISM) radio bands are the most common nonlicensed bands. They are split into three main groups: o Sub-1 GHz (also known as sub-G): There are several different bands in different areas around the world. In the United States, it is 915 MHz. In Europe, they are 868 MHz and 433 MHz (also some limited application in the United States). Used in newer low-power wide-area network (LPWAN) technologies. o 2.4 GHz: This is the most commonly used frequency band. Examples include Wi-Fi, Bluetooth, ZigBee, etc. This frequency is also used by cordless phones and microwave ovens, which may introduce noise. o 5.8 GHz (also known as 5 GHz): This is used for “dual-band” Wi-Fi. It allows for higher bandwidth but at a reduced range (especially when indoors). o There are also several less common higher frequency bands, including 24 GHz and 61 GHz. These are typically for very high bandwidth point-to-point connections with minimal range. One example is wireless high-definition (HD) video for home theater systems. Bandwidth • The difference between the upper and lower frequencies used for data transmission. • In this context, bandwidth does not refer to data throughput. Minimum data rate Minimum data transmission rate for the uplink (device to base station). Maximum data rate Maximum data transmission rate for the uplink (device to base station). Maximum transmission power • The maximum effective radiated power (ERP) allowable based on local regulations. • Like frequency range, transmission power may vary by country or region. By default, we listed the maximum transmission power per European communications standards. • Transmission power is often expressed in units of dBm (decibels [dB] with reference to one milliwatt [mW]). This unit can be converted to watts using an online calculator. 3 • Device power consumption is a different field. The onboard circuitry may have its own power requirements, and it is not 100% efficient in converting electricity into radiated power. • Devices may transmit effectively at lower power for close base stations and/or lower data rates. Rural transmission distance • The maximum distance a device can effectively transmit data with a clear line of sight to the base station (tower). • Transmission distance can be limited by the environment (maximum transmission power, attenuation, antenna sensitivity) or by the wireless network modulation (due to time delay). Network topology • The communication arrangement of nodes (devices attached to a network) and gateways (bridge between devices and the cloud). • Examples include: o Point to point: A single link between two nodes. o Star: A traditional wireless network architecture where one base station links to several nodes. o Tree: A hybrid topology typically with several star networks connected on a backbone bus. o Mesh: A free-form network where nodes link to each other dynamically to pass data along to its final destination.