The implementation of the new rules of the Ministry of Indus
On November 28, the Ministry of Industry and Information Technology issued Announcement No. 52 of 2019, which further standardized many matters of micropower short-range radio transmission equipment.
After the announcement, some people in the industry believe that according to the new regulations, the low-power, long-range wireless LAN standard for LoRa, LoRa, will be cold due to some restrictions of the new regulations. Another person believes that the domestic LoRa is not limited, but the new regulations affirm that LoRa can be used for wireless networking, which is good for LoRa.
So what's going on?
First, Article 7 of the new regulations of the Ministry of Industry and Information Technology states:
In this regard, the Radio Regulator made a detailed interpretation:
So what does this requirement have to do with LoRa? LoRa is a low-power, long-range wireless LAN standard created by the US company Semtech. The LoRa work uses the unlicensed ISM band, but the use of ISM bands in different countries or regions is different. The following table shows some of the frequency bands used in the LoRa Alliance specifications:
It can be seen that LoRa's ISM frequency bands include 470-510MHz, 865-867MHz, 867-869MHz, 902-928MHz, 920-925MHz and so on. Among them, the working frequency band in China is 470-510MHz. The main application area of the technology is the "meter".
It can be seen that in the previous announcement of the Ministry of Industry and Information Technology, it was explicitly mentioned that starting from January 1, 2022, the suspension of production or import does not comply with this announcement but meets the requirements of the "Release of
Note that the words marked in red above do not meet the requirements of this announcement but comply with the requirements of the "Notice on Issuing the" Technical Requirements for Micropower (Short Range) Radio Equipment "", which will stop production or import. That is to say, in addition to the prohibited equipment that is not specified in this notice, the civil meter in the "Notice on Issuing the" Technical Requirements for Micropower (Short Range) Radio Equipment "" also needs to stop production import.
Let's look at the provisions on metering in the "Notice on Issuing the" Technical Requirements for Micropower (Short Range) Radio Equipment "" (Xin Bu Wu  No. 423):
In other words, LoRa equipment that originally met the above requirements, including in the 470-510MHz frequency band, will have to stop production and import. This may be one of the reasons why many people say LoRa is cold.
However, in the No. 57 announcement of the Ministry of Industry and Information Technology this time, the first article clearly stated that "the production or import is sold and used in China and is in compliance with the" Catalogue and Technical Requirements for Micropower Short Range Radio Transmission Equipment "(see Annex) Radio transmitting equipment does not need to obtain radio frequency use licenses, radio station licenses, and radio transmission equipment type approvals, but it shall comply with laws and regulations such as product quality, national standards, and relevant national radio management regulations. "
Then let's take a look at the regulations of the meter and working requirements of the 470-510MHz frequency band in the Catalog and Technical Requirements of Micropower Short-range Radio Transmission Equipment (that is, the domestic Lora must be in this frequency):
It can be seen that the corresponding requirements are:
1. It is limited to networking applications in small buildings such as buildings, residential quarters and villages, and can be transmitted on a single channel at any time. This limits the use of LoRa in China. This also makes LoRa's previous smart city application prospects hopeless in China.
Compared with the 2018 version of "Technical Requirements for Micro-power Short-range Radio Transmission Equipment (Consultation Draft)", we can also see an obvious change, mainly removing the "used for electricity, heat, water, gas and other public metering services "", Meanwhile, it is used in "small-scale networking applications such as construction buildings, residential quarters, and villages, and can only work on a single channel at any time." A "limit" is added in front of it.
One of the biggest advantages of LoRa is the LoRawan protocol formulated by the LoRa Alliance, and the other is the core base station gateway 1301 chip. The development path of the LoRaWan protocol from 1.0 to 1.01 to 1.03 to 1.1, including new functions such as roaming access switching added to the 1.1 protocol, are all evolving in the direction of smart cities and operator networks. However, under China's current policy, These have been restricted!
2. Transmit power limit: 50mW (e.r.p); Transmit power spectral density limit: 50mW / 200kHz (e.r.p) if the occupied bandwidth is less than or equal to 200kHz; 10mW / 100kHz (e.r.p) if the occupied bandwidth is 200-500kHz. "Single continuous transmission time <1 second", "Emission power spectral density limit occupied bandwidth is less than or equal to 200kHz".
So what impact will these restrictions have on LoRa?
▲ LoRa's air transmission time is affected by the bandwidth BW, encoding rate, spreading factor, and packet size. The combination of these parameters also determines the requirements of various application scenarios. Generally speaking, the smaller the spreading factor, the larger the bandwidth, and the shorter the use time. It can be seen that if the limit is <1 second, taking a data size of 105 bytes as an example, if at the same time the bandwidth is limited below 200 kHz, only BW125 and SF7 to 9 can be selected, which is equivalent to the loss of LoRa spread spectrum technology. Advantage.
▲ According to the LoRaWan agreement of the LoRa Alliance, the larger the spreading factor, the smaller the size of the valid data packets that can be transmitted. For example, when SF10 ~ 12, the maximum data packet size is only 51 bytes. If it needs to meet 100 bytes, Data packets need to be transmitted over a distance of more than 1 km. The previous method was to use a non-LoRaWan protocol to achieve this, but the transmission time will be greater than 1 second. Now the new regulations must be less than 1 second. This means that this The method of using a private protocol is also blocked!
Generally, in an unobstructed environment, the larger the spreading factor is, the longer the transmission distance is. Even at a short distance with a low spreading factor, a stable communication distance above 3KM can be easily achieved. However, under the conditions of shielding the environment, it is necessary to ensure that the industry consensus of 90% correct transmission rate, the lower the spreading factor, the shorter the distance.
According to foreign experimental data, if the spreading factor is limited to the range of SF7 ~ 9, to ensure a transmission accuracy rate of more than 90%, the transmission distance of 100 ~ 200 meters may be even worse! Due to the 1 second limit, Want to guarantee a certain communication packet size, only a low spreading factor can be used, but it will inevitably cause a significant reduction in effective distance, completely losing the long-distance communication advantages that LoRa was proud of!
The advantage of LoRa is that it is long-distance and low-power transmission in remote suburbs, which is complementary to operators. If it is to be used in a small range now, it is tantamount to self-defeating martial arts and competing with various other Wi-Fi, BLE, and Zigbee wireless technologies. No matter in bandwidth, real-time performance, and bidirectional control, LoRa is not dominant and is subject to everywhere. The final possible result is that the country will abandon the LoRaWan standard agreement and return to the state of the previous private agreements of various players.
The LoRa Alliance ’s development of the LoRaWan protocol ’s evolutionary route itself is for the development of network operators ’networks. Therefore, LoRaWan ’s agreement adds many restrictions that comply with local national regulations, such as the emission duty cycle of less than 1%, LBT ( listen before talk), etc. Now that the big network is restricted in China, many restrictions of LoRaWan were completely meaningless in China. The final result is likely to be abandoned by the developer, which may have more serious consequences! For example; security issues, stability issues, compatibility issues, standardization pioneered by the lora Alliance, and low thresholds will be completely abandoned in China. The industry may return to the savage growth state of early blooming flowers!
It can be said that the new rules of the Ministry of Industry and Information Technology have not been misunderstood by many people before, "Lora is going to be cold", but it is definitely not "good"!
It is worth mentioning that, in the field of Internet of Things, LoRa and NB-IoT are direct competitors, but compared to NB-IoT, the advantage of LoRa is that users can complete LoRa network deployment without relying on operators. , Not only faster deployment, but also lower cost. The cost and energy consumption of NB-IoT are high, and operators also need to charge. This also makes LoRa a clear advantage in closed areas such as communities, farms, and industrial parks, especially indoor and underground environments with weak NB-IoT signals.
However, it should be pointed out that LoRa chips are in the fundamental core position in the entire industry chain. Currently, Semtech Corporation in the United States is the core supplier of LoRa chips and holds the core patents of LoRa's underlying technology. There are two main Semtech customers. One is a semiconductor company that has obtained Semtech LoRa chip IP authorization; the other is a manufacturer that directly uses Semtech chips as SIP-grade chips, including Microchip. This also means that, once an incident similar to the US against ZTE and Huawei occurs, the domestic LoRa will inevitably be subject to others.
It is worth noting that after several years of development, the LoRa Alliance currently has more than 500 members worldwide and has deployed LoRa networks in more than 100 countries around the world. These networks cover the United States, Canada, Brazil, China, Russia, India, Malaysia , Singapore and other countries and regions. Among them, in China, including Alibaba, Tencent, ZTE, China Unicom, Tower Corporation, and Guizhou Broadcasting and TV are all active promoters of LoRa technology.
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