What is a good Internet of Things connection solution?
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Date：2019-07-29
Today there are many very different Internet of Things applications, ranging from sending several bytes of soil sensors every few hours to sending megabytes of data to driverless cars. Many applications depend on good connectivity, so the problem arises... What is good connectivity in the Internet of Things?
In planning the Internet of Things network, there are three main factors to choose from: power consumption, scope and bandwidth/data rate. If your sensor can be connected to a stable power supply, it's easy to achieve a good range and bandwidth, but in most applications, this is not the case, and batteries must be used, so a trade-off must be made. Other important factors include the cost of communication chips and equipment, as well as reliability. Based on all these factors and tradeoffs, there are a variety of connection options available, such as Wi-Fi, LoRaWAN, NB-IOT, LTE and so on.
To facilitate understanding of these options, group them:
1. Unlicensed: WiFi, Bluetooth, RFID/NFC, ZigBee, Z-Wave
2. Cellular/License: 4G LTE, LTE Cat-M, Nb-IoT and 5G
3. LPWAN: sigfox, LoRa/LoRaWAN, Ingenu, Weightless
4. Satellites
5. Mixing/Combination: The First Four Types of Combination
These five groups can be well displayed on the bandwidth and scope chart, so it is easy to understand and choose the appropriate connection solution for the appropriate Internet of Things applications:
1. Unauthorized
The unauthorized network does not require the permission of the frequency regulator to use the frequency. A typical example is a Wi-Fi network that anyone can freely use. In contrast, a smartphone can connect to a licensed 4G LTE base station. LTE frequencies are licensed by your operator, and in fact the annual cost is quite high. One might ask: Why do people pay for something they can get free of charge? By using an unauthorized solution, your transmission power is limited, so it cannot be transmitted far away, and you are usually disturbed by other users, because no one protects or restricts the use of the same thing by other users. Frequency. However, if you don't want to pay any fees to telecom operators, unlicensed is definitely a good way to build small private networks. The popular unauthorized bands are 433 MHz, 868 MHz, 915 MHz, 2.4 GHz, 5.4 GHz and 60 GHz.
The most popular unauthorized standard is Wi-Fi. In the latest AC version, it can provide speeds exceeding 1 Gbps, but its range is usually limited to 100 meters. In addition, new Wi-Fi standards have been developed for the Internet of Things: WiFi HaLow (802.11ah) and HEW (802.11ax).
Another very popular unauthorized network is Bluetooth and Bluetooth Low Power Consumption (BLE), which are ideal for the Internet of Things, but with a relatively small coverage (less than 30m). But compared with Wi-Fi, BLE is more energy-efficient, easier to set up, and has stronger anti-jamming ability (working better in noisy environments), but it has smaller scope and lower capacity. The latest version of Bluetooth, Version 5, brings many useful functions, such as four times the range, two times the speed, it supports the grid, so it is easier to build a larger Bluetooth network than before.
Other unauthorized standards are ZigBee, which has been on the market for more than 10 years, and very similar Thread, which are mainly used for Google and Nest smart home applications. There is also Z-Wave, which is a standard designed for home automation.
2. Honeycomb/License
Cellular licensing networks are based on the so-called 3GPP standard (third generation partnership project), and 2G/GSM, 3G UTMS, 4G LTE and most of the current 5G mobile communications are also based on this standard. Today's smartphones mostly use a 4G LTE network, which can provide over 100 Mbps of speed, wide range and good reliability, but on the other hand, we all know that we charge smartphones every two days or even every day. In order to overcome this power consumption problem, 3GPP has issued low power, narrowband but still licensed network standards. The two most famous types are LTE CAT-M and NB-IOT. These networks provide services based on SIM cards, and they provide coverage, security and quality of service similar to 4G LTE networks. One of the greatest advantages of cellular Internet of Things is that current LTE base stations can easily be upgraded to CAT-M or NB-IOT, so they can cover the whole country in a few days, while other new entrants in the market have to spend a lot of time and energy building the network from scratch.
3. LPWAN (Low Power WAN)
One of the most popular LPWAN standards today is LoRa. LoRa uses an unauthorized < 1 GHz frequency, thus achieving good coverage and indoor penetration. LORA uses spread spectrum technology to enhance the robustness of the link to interference, and provides good gain and coverage. (Source: iothome) LoRa can support up to 15 kilometers of distance (rural/suburban, urban mostly 1-2 kilometers) and bandwidth ranging from hundreds of bytes to 50 kbps. The open protocol used to build regional or national networks is called LoRaWAN. LoRa has a good level of security and can even be used for rough positioning without GNSS.
Another major Lpwan player must be sigfox. In contrast to open standard LoRa, sigfox is a proprietary protocol and a closed system, so sigfox designates a network operator in each country or region and controls the backend and connection, whereas Internet of Things customers only need to use the system and pay the cost of connecting to sigfox network. SigFox also uses an unauthorized < 1 GHz frequency, but because its capacity is even smaller than LoRa (about 100 bps, up to 140 messages per day), SigFox
