Abstract: As an emerging technology of LPWAN (Low Power Wide Area Network), NB-IoT has gradually improved. This article mainly introduces the summary of the nb-iot chip hungry manufacturers and the characteristics of the nb-iot chip as the center.
NB-IOT is called NarrowBand-Internet of Things, a narrowband Internet of Things. A technology that belongs to the Internet of Things. As an emerging technology of LPWAN (Low Power WAN), NB-IoT is favored by operators because of its advantages of low power consumption, low cost, wide coverage, and massive nodes, and it can seamlessly connect with 2G and 3G in licensed bands. And accept. Especially in 2017, according to statistics, more than 50 operators around the world are deploying NB-IoT. Huawei, Qualcomm, and Zhongxingwei are also actively promoting the NB-IoT chip, network, and deployment industry chain. work hard.
Why does NB-IoT appear?It is predicted that in 2016, 6.4 billion IoT devices will be connected to the network every day, and 5.5 million devices will be connected to the network. One of the foundations of the “Internet of Everything†is the transmission of data, and the data transmission capabilities of different IoT services. Real-time has different requirements.
According to the different transmission rates, IoT services can be distinguished by high, medium and low speed:
High-rate services: mainly use 3G, 4G technologies, such as vehicle-mounted IoT devices and surveillance cameras, and the corresponding business features require real-time data transmission;
Medium-rate services: mainly use GPRS technology, such as lockers in residential quarters or supermarkets, which are used frequently but not in real-time. The requirements for network transmission speed are far less than high-speed services;
Low-rate services: The industry has classified the low-rate service market into the LPWAN (Low Power Wide Area Network) market, which is a low-power WAN. At present, there is no corresponding cellular technology, and in most cases, it is supported by GPRS technology, which brings about a problem of high cost and low penetration of low-rate services.
That is to say, the current low-rate business market is in urgent need of development, and the low-speed business market is actually the largest market, such as fire extinguishers in buildings, various monitors used in scientific research, and the frequency of such devices in life is very low. But the total number of collections is considerable, and the collection of these data is used for various purposes, such as improving the configuration of urban equipment.
NB-IoT is a new narrowband cellular communication LPWAN (Low Power Wide Area Network) technology that can help us solve this problem.
NB-IOT chip features:1. Spectrum is narrow: 200kHz;
2. The terminal transmits a narrowband signal to increase the power spectral density of the signal, improve the coverage gain of the signal, and improve the spectrum utilization efficiency;
3.0 same packet repeated transmission can also obtain better coverage gain;
4. In addition, the technology reduces the activation ratio of the terminal and reduces the complexity of the baseband of the terminal.
5. NB-IOT four major capabilities: wide coverage, massive connectivity, lower power consumption, lower chip cost.
6. Based on the existing cellular network technology, NB-IOT can quickly support the industry market demand by upgrading the existing network, becoming the fourth mode on the GUL network.
Advantages of NB-IoT chip: 1. Wide coverageNB-IoT technology can achieve coverage gain of more than 20dB than GSM, and the coverage area is expanded by 100 times. It can also be covered in underground garages and underground pipelines.
Uplink tool spectral density gain 17dB (200mw/3.75kHz for NB-IoT compared to 200mw/180kHz for 2G/3G/LTE)
2-16 times retransmission mechanism gain 3-12dB (pay delay penalty, 10s, but business allows)
Compilation code gain 3-4dB
2. Large connectionNB-IoT supports 50,000 connections in a single sector, which is 50 times higher than current (2/3G/4G is 14/128/1200 respectively). Currently there are about 5 million physical sites around the world, assuming NB-IoT is fully deployed. The number of IoT terminals accessible to three sectors per site will reach 450 billion.
Narrowband technology: Uplink equivalent power 36 channels * 23dBm, boost channel capacity
Reduce air interface signaling overhead and improve spectrum efficiency
Base station optimization: independent admission congestion control and terminal context information storage
Core network optimization: terminal context storage and downstream data cache
3. Low power consumptionNB-IoT terminal sends 200Byte messages once a day, and AA battery standby time is 10 years.
A single quick pass time has been shortened
The terminal works in the energy-saving mode (PSM) 99% of the time. This energy-saving mode is different from the energy-saving mode of the mobile phone. The terminal is still registered in the network, but the signaling is unreachable. The terminal is in deep sleep, and the power consumption of the terminal is only 15 microwatts in 99% of the time. It takes a long time to sleep, which can reduce the frequency of the terminal listening to the network.
Because the Internet of Things does not change as fast as a mobile phone, mobility management can be simplified.
4. Low costAt present, the cost of a single module will not exceed $5, and the goal is to do about $1.
180kHz narrowband, reducing chip complexity;
Simplify the protocol stack (500 Bytes) and reduce on-chip Flash/RAM;
5. Low sampling rateSingle antenna, half duplex, low RF cost;
The peak-to-average ratio is low, and the single-chip SOC has a built-in 23dBm transmit power.
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