An article to take you to know LPWA communication technology

Abstract: In order to meet the connection needs of more and more long-distance IoT devices, LPWA applications were born.

This article is shared from the HUAWEI cloud community " common IoT communication technology LPWA communication technology ", author: cat who loves to eat bread.

If you are more concerned about the Internet of Things circle, you must have heard of the term LPWA. Even if I haven't seen it, I have also scanned the technical keywords of LoRa, SigFox, and NB-IoT in the technology media.

In order to meet the connection needs of more and more long-distance IoT devices, LPWA applications were born. LPWAN (Low Power Wide Area Network) is a low-power wide-area network designed for low-bandwidth, low-power, long-distance, and massively connected IoT applications. Let's enter today's topic and introduce LPWA technology in an all-round way.

1 SigFox

SigFox is a French Internet of Things technology startup company, its company is called SigFox, and its technology is also called SigFox. SigFox is a technology specially designed for projects with very low throughput. Its transmission power consumption is very low, only 50-100 microwatts, but it can still maintain a relatively stable data connection. But, because the Internet of Things devices will generate a lot of data, and these data are stored by SigFox itself. But after all, SigFox is a small company, and it has insufficient credibility in keeping these data. It also has questions about information security, so its use is not as extensive as LoRa.

2 LoRa

It is the abbreviation of Long Range, which is different from SigFox in that it is maintained and managed by the LoRa Alliance. LoRa technology was developed by Semtech. After the joint efforts of the LoRa Alliance, they developed a network used in the LPWA field called LoRaWAN. It is an ultra-long-distance wireless transmission scheme based on spread spectrum technology to achieve long-distance and low-power requirements. This technology is mainly supported in unlicensed frequency bands. Lora can be applied to automatic meter reading, smart home and building automation, wireless early warning and security systems, industrial monitoring and control, and remote irrigation systems, etc.

3 NB-IoT

NB-IoT was first proposed by Huawei and Vodafone, and later joined some companies such as Ericsson and Qualcomm. Its characteristic is that NB-IoT is called narrowband cellular Internet of Things, so it is built on the existing cellular network. At the same time, because it is a narrowband, it only consumes about 180KHz of bandwidth, and can be directly deployed on a GSM network, UMTS network or LTE network to reduce deployment costs and achieve smooth upgrades.

4 eMTC

The last one to describe in LPWA technology is Ericsson's 4G network-based solution eMTC, which is mainly oriented to application scenarios with deep coverage and large connections. Compared with NB-IoT, it has a higher rate but a smaller coverage area and higher power consumption. However, although it has a smaller coverage area and greater power consumption than NB-IoT, it has the capability of voice communication. So compared to NB-IoT, it can be applied to some scenarios that require the use of voice communication functions.

5 LPWA technology comparison

Next, this article will also make a simple comparison of the above-mentioned LPWA technology. Except for NB-IoT and eMTC, the other two networks operate on the SubG unlicensed frequency band. SubG means that the frequency is below 1GHz, mainly referring to the 27MHz to 960MHz frequency band. SubG is an ideal choice for long-distance, low-power communications. Because in the case of the same power, the higher the frequency of the network, the worse the penetration ability, but the equipment in the LPWA scene, such as electricity meters, water meters, etc., are often placed in a relatively deep position, which usually has a lot of obstacles. In the above, it is very necessary to choose the low frequency band. In the table, you can also see the description of NB-IoT. Its frequency band is mainly deployed on the SubG authorized frequency band. This is because some NB-IoT networks are deployed outside the SubG authorized frequency band. The specific reasons will be described in this article. It will be explained in the following chapters. Since LoRa applied to unlicensed frequency bands and NB-IoT in licensed frequency bands are both popular LPWA technologies, they are often used for comparison. The difference between the two is:

1) Different lineups LoRa was researched by the American self-employed Semtech, and NB-IoT is a standard formulated by the official 3GPP Mobile Communications Association. LoRa is basically the upstream and downstream industry chain arranged by a company from Semtech, but NB-IoT is the joint operation of upstream and downstream companies in the entire communications industry. For example, NB-IoT chip modules are now being implemented by companies such as Huawei, Qualcomm, Samsung, and MediaTek. .

2) Frequency band usage The frequency bands used by different NB-IoT are licensed frequency bands, while LoRa uses unlicensed frequency bands. The authorized frequency band is authorized by the Ministry of Industry and Information Technology. Except for the authorized operators, all other individual enterprises cannot use the frequency band. If it is used, it will be illegal. The radio management department will come to check the water meter. The unlicensed frequency band is the frequency band that the Ministry of Industry and Information Technology did not say for anyone to use it. Therefore, if an individual or enterprise uses the working frequency band of LoRa to do other things, it will cause serious interference to the LoRa equipment in this area, making the network unusable. Therefore, the quality of the NB-IoT network with official background is definitely better and higher quality.

3) LoRa needs to be built by the enterprise itself. NB-IoT operators have already established the operators and do not operate the LoRa network. If the enterprise wants to use LoRa, it needs to purchase a complete set of network operation software and hardware such as base stations, network equipment, servers, etc., and complete the network Build it and operate it yourself.

At present, the three major operators of NB-IoT have completed the construction of base stations and network opening in China. Just like using mobile phone SIM cards, companies only need to purchase NB-IoT SIM cards from operators, and then insert them with NB-IoT modules. You can pay to use the equipment in the group.

4) What are the advantages of LoRa? In fact, for 90% of enterprises, LoRa really has no advantage. Unless companies want to use the Internet of Things in rural areas, remote mountain areas, independent factories, etc. (such as smart farms, smart factories), there is really no coverage of the operator's NB-IoT network, and they have no choice but to think of building their own LoRa. Furthermore, very large enterprises or governments are afraid of using the operator's network to be insecure, such as data theft, so they would rather build their own network and maintain it instead of trusting the operator. The above is the big difference between NB-IoT and LoRa.

6 Comparison of wireless communication technologies

The above three types of wireless communication technologies include many different network communication technologies, and these three types can be applied in the field of Internet of Things. How should developers choose and how to weigh and use them? Figure 4-6 can answer this question very well. Through this figure, we can know what kind of network should be used in specific situations. The two coordinate axes of this picture are transmission rate and transmission distance, which also correspond to the needs of different scenarios of the Internet of Things. According to different data rate requirements, the scenarios can be roughly divided into three categories. One category is the highest data rate requirements such as video surveillance, car networking, the second category requires higher rate requirements such as intelligent logistics, vehicle management, etc., the third category is Industries that require less speed, such as meter reading. Of course, these scenarios can be further subdivided if it is specific to the propagation distance, so it can be roughly divided into these six different networks for different needs. As mentioned above, the most suitable network is the best network. In addition to considering the transmission distance and transmission rate, it is also necessary to consider the cost to select the most suitable network for application. In the solution, so as to obtain the greatest benefit.

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