"In the application of the Internet of Things in the future, most devices only need to transmit very little data, so low-power wide area network technology (LPWAN) is very suitable for the connection of low-speed IoT devices. Domestic operators are actively deploying NB-IoT /eMTC and other LPWAN networks.” said Shen Zhou, technical director of Shanghai Unicom’s Internet of Things Operation Center, at an LPWAN seminar. According to relevant data, the scale of my country's Internet of Things market will exceed 1.8 trillion yuan in 2020, and the total number of Internet of Things connections will reach 1 billion, of which LPWAN technology will provide 730 million connections.
Since the NB-IoT core standard was frozen in 2016, discussions on low-power wide area network technology (LPWAN) have rapidly increased, and the market has continued to heat up. In my country, in addition to the NB-IoT and eMTC supported by the three major operators, LoRa, which has been applied in foreign markets in the early years, has quickly entered people's field of vision from a niche technology.
However, different technical genres may cause confusion for application companies: What are the technical characteristics of NB-IoT, eMTC and LoRa, and what are the advantages and disadvantages? Does my product need to use LPWAN technology, and which one should I choose? In which application is LPWAN technology most likely to explode?
The annual shipment of chips exceeds 10 million, what is the magical power of LoRa?
Compared with the NB-IoT launched in the last two years, LoRa has been widely used abroad. Dr. Liu Yang, Director of Business Development of Semtech, said at an LPWAN seminar that after 5 years of development, LoRa has built 46 public networks and 350 trial networks on all continents around the world, and shipped more than 10 million chips a year. piece.
Dr. Liu Yang pointed out that compared with new cellular technologies such as NB-IoT, the biggest technical feature of LoRa is the use of linear spread spectrum technology, which can receive signals at 20db below noise, so it can effectively operate at low rates and low power consumption. For long-distance transmission. According to the test data of the cooperation between Semtech and Cisco in the United States, the transmission distance of LoRa can reach 50 kilometers without obstruction.
Secondly, the power consumption of LoRa is lower than that of NB-IoT. The reason is that the protocol layer of LoRa is simpler, and the ratio of the highest power to the average power of its wireless module is low, and the circuit design efficiency is high. In the case of deep sleep, the current of LoRa is less than 2uA, the waiting state is 2mA, the receiving state is less than 10mA, and the transmitting power is 0.1w, which greatly extends the service life of the battery.
Finally, LoRa's network deployment is more flexible and can be deployed on demand. Dr. Liu Yang said that LoRa's base stations and routers can be very small, and the miniature base stations supported by the palms of the hands and the indoor gateways that are only the size of ordinary routers were displayed on the spot, which is similar to the size of a tower standing on a mountain in people’s impressions. The base stations are very different. The small size also reduces the cost of the base station, which can achieve a price of 100 US dollars. A deeper network coverage can be achieved through small base stations and micro base stations, which is very applicable in some realistic environments.
Figure 1: Technical characteristics of LoRa
Xie Lichao, deputy general manager of Ruixing Hengfang Network (Shenzhen) Co., Ltd., further added that in some application scenarios, the density of base stations cannot achieve full coverage of the Internet of Things network. For example, in the application of LPWAN gas meters, many gas meters are placed in iron boxes, which belong to the signal shielding environment. At this time, the density of the base station is by no means ten kilometers or several kilometers advertised by everyone, it is probably five or six hundred meters. Similar to this is the application of LPWAN in elevators, where the density of base stations must reach 200 meters. For another example, in the urban village of Shenzhen, there is no cellular network coverage at all. At this time, if you want to realize the application of the Internet of Things, you need to flexibly deploy small base stations/micro base stations according to the number and location of nodes. In these application scenarios, the flexibility of LoRa network deployment is reflected.
Xie Lichao also mentioned some of the challenges currently facing LoRa. First, it is in the unlicensed frequency band, with more serious frequency pollution, more privatized networks, and poor security; second, the network construction and maintenance are difficult and costly, especially for small businesses and ordinary consumers; third, The fragmentation of the Internet of Things is serious, and wireless modules need to be customized; fourth, the lack of support from operators makes it difficult to achieve city-level network coverage.
In response to the difficulty of network construction, professional LoRa Internet of Things operators have emerged in China. For example, Hangzhou Luowan Information Technology Co., Ltd. provides LoRa system-level solutions including LoRa gateways, cloud platforms and self-built base stations, and is used in wireless smoke detectors, water and electricity meters and other products.
Figure 2: Hangzhou Luowan Information Technology Co., Ltd.'s LoRa-based fire-fighting IoT solution
In addition, in May 2017, the Computer Network Information Center (CNIC) of the Chinese Academy of Sciences announced that LoPo-IoT has achieved network coverage of 803 square kilometers in Nansha District, Guangzhou. Huang Kaide, deputy chief engineer of the Computer Network Information Center of the Chinese Academy of Sciences in Guangzhou, said that LoPo-IoT is an LPWAN technology based on LoRa. The data is connected to the national Internet of Things identification platform to ensure the uniqueness and security of data. There are a wide range of application markets in such fields.
Figure 1: CNIC has built 118 base stations so far, basically achieving full network coverage in Nansha District, Guangzhou
Module manufacturers and operators are actively deploying, and next year may achieve large-scale commercial use of NB-IoT
NB-IoT technology is very new, and it has only been two years since the core standard was frozen in 2016. However, operators are not unfamiliar with NB-IoT, because it is essentially a standardized cellular technology. Operators do not need to relocate sites for this purpose. They can achieve rapid deployment on the basis of existing base stations. Strong support from operators.
"In the future IoT applications, most devices only need to transmit very little data. Therefore, NB-IoT will be the best choice for low-speed IoT devices. Based on this, domestic operators are actively deploying NB-IoT. IoT network." said Shen Zhou, technical director of the Internet of Things Operation Center of Shanghai Unicom.
Shen Zhou said that Shanghai Unicom can be said to have adopted a very radical attitude to promote the development of NB-IoT: in July 2015, the first sample test began; in 2016, it was the first to provide NB-IoT IoT application experience in Disneyland; 2017 In May 2015, the full coverage of Shanghai's NB-IoT network was achieved. Up to now, NB-IoT is already in an explosive period. In communicating with the government, Shanghai Unicom found that they have a very large demand for smart cities. Smart parking, smart smoke detectors, smart street lights, water meters and gas meters are likely to be the first to achieve large-scale commercialization.
At present, the biggest problem hindering the development of NB-IoT is cost. "From what we know, the cost of the NB-IoT module was 100 yuan at the beginning of the year. It can now be reduced to about 60-70 yuan, but it is still much higher than the price of the 2G module at 20-30 yuan, which is not conducive to NB. -The popularity of IoT." Shen Zhou said.
So to what extent has the NB-IoT module been developed? At last week's Internet of Things exhibition, mainstream NB-IoT manufacturers such as Long Shang, ZTE IoT, Simcom, MG, Youfang, Telit, Ublox, Qi Jun, etc. all participated in the exhibition. Let us see what they say.
The on-site staff of Longshang Technology pointed out that almost all mainstream module manufacturers have not achieved mass production of NB-IoT modules. In 2017, Longshang launched the NB-IoT/eTMC/GPRS multi-mode module A9500 based on Qualcomm chips, and has shipped more than 10,000 sets so far, but it is mainly for customer testing or application pilot use. Application scenarios include remote meter reading, smart parking, smart street lights, environmental monitoring, smart agriculture, livestock breeding irrigation, smart trash cans and other smart city fields. It is expected that in September this year, Long Shang will launch the NB-IoT single-mode A9600 module.
Figure 3: Longshang A9500 Development Board
Figure 6: Longshang wireless communication module
ZTE IoT currently has only one NB-IoT module ME3612, which uses Qualcomm's MDM9206 chip. According to the on-site staff of ZTE IoT, the ME3612 module has achieved small-scale mass production, and has pilot applications in smart manhole covers, smart street lights, smart fire hydrants, and shared bicycles. It is rumored that in September this year, ZTE will launch the NB-IoT commercial chip RoseFinch 7100 (Suzaku 7100), competing with Huawei and Qualcomm in the NB-IoT chip market.
Figure 4: ZTE's NB-IoT smart well monitoring system in Jiangxi
It is worth mentioning that Quectel, which ranks among the top in shipments, did not participate in the exhibition. Instead, Quke, which is closely related to it, brought the L700 wireless module based on Qualcomm's MDM9206 chip to the exhibition. Since the L700 has just been released, its shipments are not large. In addition, Qi Jun also demonstrated the ML3500 NB-IoT wireless communication module, but it is still in the testing and development stage and is expected to be launched within this year.
Figure 5: Qijun NB-IoT wireless communication module ML3500
Figure 7: SIMCom wireless communication module
Figure 8: Youfang wireless communication module
Shared bicycle or smart lock, which one will be the explosive application of LPWAN
From the perspective of technical characteristics, LoRa, NB-IoT, and eMTC all have the characteristics of low power consumption, low cost, wide coverage, and large connections. So, how to choose LPWAN technology for application enterprises?
Ms. Zhao Ming, product director of SIMCom Wireless Technology Co., Ltd. pointed out that users should choose the appropriate technology according to their needs, product features and application scenarios. Shen Zhou of Shanghai Unicom also expressed a similar view: "We did not force users to use NB-IoT. If it is a manhole cover, water meter and other products that require extremely low power consumption, you can choose NB-IoT; if it is for low cost And low traffic, it is recommended to use 2G modules first, and it’s not too late to choose after NB-IoT and eMTC are commercially available on a large scale."
Xie Lichao of Ruixing Hengfang analyzes from the technical level, the general LPWAN technology improves the sensitivity by limiting the bandwidth. For example, NB-IoT limits the upstream bandwidth. LoRa does not need to be like this, and its unique linear spread spectrum technology ensures symmetrical uplink and downlink bandwidth. If true two-way communication is required, such as grid monitoring, LoRa may be a better choice.
With the popularization of LPWAN technology, many products other than traditional manhole covers, water/electricity/gas meters, street lamps, and smoke detectors have appeared, indicating that LPWAN has sounded the clarion call to replace part of the 2G/BT/WiFi market. For example, a company in Fujian launched an NB-IoT heart rate belt, evolving traditional Bluetooth to NB-IoT transmission. Another example is the current most popular shared bicycle market. In the past few months, ofo bicycles cooperated with China Telecom and Huawei to launch NB-IoT shared bicycles. Qualcomm also announced plans to cooperate with China Mobile and Mobike to launch China's first eMTC/NB-IoT/GSM (LTE Cat M1/NB1 and E-GPRS) multi-mode field test.
It is reported that SIMCom is the largest wireless module supplier in the shared bicycle market. Zhao Ming said that LPWAN solves the two problems of shared bicycles. First, the number of 2G network connections is limited, and if a large number of users connect in some areas, there will be network congestion; second, the battery life is limited.
However, the industry is cautious about the application of NB-IoT in shared bicycles. Zhao Ming said that SIMCom is still supplying 2G modules for shared bicycles. NB-IoT shared bicycles are still in the experimental stage, and module manufacturers are also waiting and watching. Because NB-IoT does not support base station handover in a mobile state, there is a waiting process for the user to disconnect and reconnect when parking. In contrast, eMTC with mobility is more suitable for sharing bicycles. Longshang Technology, which supplies ofo bicycles, also expressed similar views.
Of course, the application of NB-IoT in shared bicycles cannot be beaten to death. With the development of NB-IoT technology, it is possible to solve the above-mentioned problems. It is reported that 3GPP has carried out a series of enhanced technologies for NB-IoT in Re-14 and completed the core specification in June 2017, which includes positioning and mobility functions. In the future, the application of NB-IoT can be expanded to asset tracking and wearable fields.
In addition to sharing bicycles, smart door locks may also be the next explosive application of LPWAN. According to statistics released by Analysys, the shipment of smart door locks in my country was 2 million in 2015 and 4 million in 2016. It is expected that shipments in 2017 will double to 8 million.
Shen Zhou pointed out that smart door locks will break out completely at the end of this year and early next year. LPWAN technology meets the pain points of low power consumption and low cost of smart door locks, and can help the government's public rental housing and youth apartment market to achieve multi-functional management.