Reasonable IoT Expectations

Think carefully about the size of the data you want to collect and transmit, smf how many individual values you need to transmit (channels), and how frequently you want to transmit that data. The table below is intended to provide a coarse guide between the sensible and realistic options. Note the extremely important difference between transmission/recording rate and event frequency rate. Your sample / tranmission rate should be 10x higher than the event frequency rate.

Continuous Data Reading & Streaming
Event Frequency (1)	Transmission Rate (2)	Comments
< 10,000 Hz	< 100,000 Hz	Close proximity (< 2800 mi). Modern microcontrollers can easily read and analyze single channel of data at 10 kHz or higher. Microcomputers can do much more.
< 1,000 Hz	< 10,000 Hz	Shock / impact events.
< 500 Hz	< 5,000 Hz	Vibration signals, such as rotating equipment (motor or pump rotating shaft, bearings, etc.). (3)
< 100 Hz	< 1,000 Hz	Nearly all mechanical systems except for vibration and shock/impact (see above) have a frequency content that is less than 100 Hz, and many 30 Hz or less. (3)
< 25 Hz	< 250 Hz	5G cellular with a source to destination distance that is less than 2800 miles.
< 6.7 Hz	< 67 Hz	Cat M1 (LTE Cat-M) is a 4G/5G technology with a typical message size limitation of 1500 bytes.
< 5 Hz	< 50 Hz	4G cellular with a source to destination distance that is less than 2800 miles.
< 4.2 Hz	< 42 Hz	Pushing a stream of data to the cloud is limited to these rates by internet latency. The server must be geographically close to the connection source, otherwise the latency will be higher, and those rates much lower.
< 1.1 Hz	< 11 Hz	LoRa wireless transmission of several measurements within a 16 byte 256 AES encrypted packet. Wireless range has limitations.
< 1 Hz	< 10 Hz	CAT-4 is an IoT-specific LTE variant with maximum uplink speeds of 50 Mb/s.
< 1 Hz	< 10 Hz	CAT-1 is an IoT-specific LTE variant with maximum uplink speeds of 5 Mb/s.
< 0.01 Hz	< 0.1 Hz	Cat NB1 (formerly known as NB-IoT) is a 4G/5G technology with a latency of 1.6 to 10 seconds. Uplink speeds are 66 kbps. This technology is best employed for low power IoT applications that do not require frequent data publishing.

(1),(2): The transmission rate is the (sample) rate at which the signal of interest (event frequency) is recorded. The sample rate needs to be 10x or more larger than the frequency content of what is being measured (event frequency) in order to avoid aliasing issues. All of this pertains to a single channel or stream of data. The values in the table above for event frequency and transmission rate were derived from conservative latency values, considering they are for continuous streaming IoT applications.

(3) The continuous sampling requirements for these types of signals require local processing with an edge device. Short duration events may be processed / analyzed by an edge device, and then the results of the data analysis may be (optionally) wirelessly transmitted.

Latency is the total round trip time from a device, to the destination on the internet, and back. Latency is generally more important than bandwidth for small data packets such as those sent by IoT devices.

Data Packet Sizes & Cost

Fees vary widly from one IoT platform to the next.

Other Considerations

Wired Ethernet transmission range is limited to 100 m.

Internet provided by fiber-optic cable transmission has speeds of 25 Mbps to 100 Gbps

Large amounts of raw data may be stored and then physically transferred to an analysis destination by solutions such as Seagate's Lyve Mobile edge storage and data transfer service, or NI's Edge Storage and Data Transfer Service (DTaaS).

The smallest HTTPS GET data size is about 455 bytes for a resumed TLS session. The first TLS session requires at a minimum 1249 bytes (on average 6449 bytes), thereafter 330 bytes for a resumed session.

Sending 46 signed floating point numbers with six significant digits (+6.534755E+06) as MQTT over TLS will have a total size of 693 bytes. A keep-alive time of 5 minutes to preserve the TLS session is required, and that data size needs to be considered for cellular data consumption.

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The information presented on this website is for the author's use only. Use of this information by anyone other than the author is offered as guidelines and non-professional advice only. No liability is assumed by the author or this web site.

Reasonable IoT Expectations

Data Packet Sizes & Cost

Other Considerations

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