You may have heard of IoT, the famous Internet of things. IoT is nothing more than the generic name for any electrical or electronic device with a “small intelligence” — that is, capable of receiving and sending information in an automated way, but not of performing data analysis directly on the device — and access to the Internet.
IoT devices have relatively small, autonomous, low maintenance hardware. Thus, they form a network and are ideal for automating smaller tasks and collecting data from environments through sensors — as they do not take up much space and work relatively independently.
The promise is to connect just about everything: from a simple light switch to cars. Thus, IoT aims to bring ease, dynamism and control to many activities, both in private life and at work.
As it is new, the possibilities of IoT have not yet been fully explored — what can or can not be done with this technology. The main “variables” to consider when finding the ideal IoT solution for each situation — considering costs and performance — are: battery life, transmission rate, responsiveness, coverage area, scalability.
The area of coverage and scalability are related to the network of devices and the forms of communication used. In this article, we will cover communication protocols, that is, the language that IoT use to communicate and/or transmit data to a server — so that the data can be treated according to the needs of the solution.
Some protocols currently used for IoT communication:
- Cellular (2G, 3G e 4G)
- MQTT IoT
- NB IoT
- Z wave
These are some examples of protocols that allow an IoT device to be connected to the Internet. In Brazil, we have some of these networks already implemented and operational:
Each of these protocols has its specificities with respect to the different characteristics mentioned previously. To find the right protocol for each business, it is necessary to compare the specifics of protocols and devices and the needs of the project. Below, we bring more information on some of the most used protocols in Brazil.
The Sigfox protocol was invented by a French company (of the same name, Sigfox). According to the company, the protocol:
- Covers an area of 5 million square km;
- Has coverage in 70 countries;
- Has 15 million connected devices.
This coverage is equivalent to approximately 3.5% of the area of all continents combined and is present in approximately 36% of countries. Compared to the cellular network coverage, Sigfox’s is very small, however, we have to point out that this network is proprietary. Therefore, its size and acceptance is considerable.
The benefits of the Sigfox protocol are:
- Long battery life, achieved through short messages, limited messaging (sending and receiving) per day, no message exchange with the network, low IoT transmission power;
- Low cost of software and hardware, through the lack of message exchange with the network, adoption of Ultra Narrow Band and low transmission power of IoT;
- Low connection cost, since the protocol uses unlicensed frequencies for transmission. In Brazil the frequency adopted is 905.2 MHz for downlink and 902.2 MHz for Uplink. The transmission rate is 600 bit/s downlink and Uplink;
- Efficiency in the use of the spectrum, thanks to short messages, daily limit of sending and receiving messages, Ultra Narrow Band technology and a pseudo random access to the physical layer of the network;
- Long range wide area network, through the use of Ultra Narrow Band technology and low transmission power of IoT.
Sigfox is indicated for simpler applications, which do not require much exchange of messages and with little data. For example, monitoring devices, sensors — that is, IoT devices that need to send only a daily status about a certain condition.
The range of a Sigfox network is approximately 10km in urban areas and 40km in rural areas, a considerable range, which can be interesting for monitoring agribusiness crops or industrial factories.
Since the data transmission network is set up by Sigfox itself, before deciding to use this protocol, it is necessary to check whether your area of operation is be covered.
The LoRaWAN protocol is owned by the company Semtech. There is an association called LoRa Aliliance, consisting of approximately 500 members, who help in the dissemination, standardization and propagation of the protocol. According to the company, there are currently 137 LoRa networks operating in 157 countries.
The LoRaWAN network uses ISM (Industrial, Scientific and Medical) bands to transmit IoT data. These bands are unlicensed frequencies ranging from 6MHz up to 244GHz (not sequentially, but at defined intervals).
In Brazil, the frequency adopted for data transmission was the range of 902MHz-928MHz, except for some frequencies of this range that are of cellular use. In the frequencies adopted in Brazil, the transmission rates are between 980bps-21.9 Kbps (download and upload).
LoRaWAN has 3 different classes of communication:
- Class A: asynchronous communication. Always started by the IoT device, anytime. After sending the message, the network provides 2 short windows of time for the server to answer. The network does not require IoT to wake up to do any control communication. Thus, the battery lasts for a long period of time;
- Class B: synchronous communication. IoT devices are synchronized to the network through scheduled times. This allows the network to send data to the IoT device with a certain latency, sacrificing battery life. Latency is programmed for up to 128s and this power consumption, although higher than Class A, still allows for a long battery life;
- Class C: in this class, the IoT receiver is permanently connected, reducing latency in communication between the server and the device. The consumption of the receiver is up to 50mW. This class is commonly used for IoT devices that are connected directly to the power grid.
Its different types of communication allow LoraWan to be more flexible and able to cover a wider range of solutions, from the simplest to the most complex. For example, sensors, machine automation etc.
The range of a LoRaWAN network is approximately 5km in urban areas and 20km in rural areas. The LoRaWAN network is built by LoraAlliance. Therefore, if you opt for this protocol, make sure your IoT area is covered.
Cat-M1 is a protocol standardized by 3GPP. 3GPP is an agency that regulates and standardizes all cellular systems (2G, 3G, 4G, 5G). That means that the Cat-M1 protocol follows an international standard and is compatible with the existing cellular network.
As we already know, virtually the entire globe has cellular coverage. Cat-M1 uses LTE technology (known in Brazil as 4G). Therefore, its operating frequencies will be a range (for example B3, B5, B7, B28, among others) within the existing 4G system.
The Cat-M1 protocol promises long battery life for its devices. The duration, of course, varies according to the function of the IoT device and the communication time, but, usually, there is years of autonomy.
Cat-M1 uses 1.4 MHz bandwidth, with average speed of approximately 300kbps (downlink and uplink), with peaks of 1Mbps. The exchange of messages between IoT devices and servers is unlimited. Latency is around 10-15ms. This low latency is due to the fact that the Cat-M1 uses part of the LTE protocol.
The range of an IoT device using Cat-M1 is 1km in urban areas and 10km in rural areas.
Given the specifications cited above, we can see that the Cat-M1 protocol can be used for IoT devices of more complex functions, which require greater intelligence, more data exchanged with servers and a shorter response time. For example, a real-time monitoring and data collection system.
Like Cat-M1, NB-IoT (Narrow Band IoT) is a protocol standardized by 3GPP. However, unlike Cat-M1, NB-IoT does not use the LTE layer. It works on the same frequencies as LTE technology, but uses only one physical resource block of LTE (200kHz bandwidth). It is as if LTE is a ferry and NB-IoT is one of the cars that this ferry carries. Frequency-wise, NB-IoT is compatible with the vast majority of frequencies used in LTE (for example, B1, B3, B5, B28, among others).
The promised battery life is long (a few years), even with frequent messaging exchanges between IoT and server. The peak download rate is 127Kbps and the upload rate is 159kbps. Latency can vary between 1.6 and 10s. The variation in latency is affected by the distance of the antenna: the farther from the antenna, the higher the latency. Coverage of an IoT device using NB-IoT is around 1km in urban areas and 10km in rural areas.
Since the NB-IoT protocol transmits less data and its latency isn’t as low. It is more suited for simpler solutions such as monitoring sensors.
Choosing the protocol for your business
Although we mention that each protocol is indicated for a certain situation, this is not a rule. It is possible to use any of these protocols for any solution. However, some of the protocols may need much more work to get the desired results.
To avoid this excessive work, which generates a higher cost in the final product, understanding the different protocols becomes an advantage during development.
Sigfox and LoRaWAN protocols are proprietary, meaning they are private technologies, and need to build their own communication networks to cover as much area as possible. This means, in turn, that their availability depends on the coverage of these particular networks.
Although their networks are growing, their coverage is still much lower than those of protocols such as NB-IoT and Cat-M1, which use the 3GPP standard. As these protocols use already existing networks, set up by Telecom operators (such as VIVO, CLARO, TIM, OI, ALGAR etc.), their coverage is much more extensive.
Thus, if your area has cellular coverage, in the 4G system, Cat-M1 and NB-IoT will work without problems. If the choice is one of the private technologies (Sigfox and LoraWAN), it will be necessary to consult their companies to know if the area is covered by the communication network (which uses unlicensed frequencies).
In addition to coverage, the type of protocol technology — in this case, whether it is proprietary or 3GPP standard — also indicates whether it is necessary to carry out the product homologation process. Devices with protocols using the 3GPP standard, such as Cat-M1 and NB-IoT, need to be homologated by ANATEL (the Brazilian National Telecommunications Agency).
Homologation is a set of tests that validate the technology being used, ensuring that it is operating within 3GPP rules. As ANATEL is the Brazilian agency responsible for telecommunications, it requires the tests and grants licenses for the use of frequencies licensed by 3GPP in Brazil.
In order for a product using these licensed frequencies to be marketed, it needs to meet these rules. Therefore, before launching any product in the Brazilian market, the product must go through the homologation process.
Here, at Venturus, we are able to do the ANATEL tests and can help you submit your products for homologation. Venturus Lab has equipment and knowledge of 3GPP standards to help you ensure your IoT devices achieve the ANATEL seal of quality.
We have an 8821C network simulator (Anristu), which simulates Cat-M1 and NB-IoT protocols. With it, we can simulate Cat-M1 and NB-IoT networks to perform ANATEL homologation tests or other specific tests that help IoT development.