Today we'll talk about one of the three 5G brothers, nb-iot Narrowband IoT, and see how nb

Let s talk about the concept firstNarrow Band Internet of Things (NB-IoT) has become a very important 5g narrowband iotresearch branch of the world s interconne...

Jul 11,2022 | Moon

Let's talk about the concept first

Narrow Band Internet of Things (NB-IoT) has become a very important 5g narrowband iotresearch branch of the world's interconnected information network between everything. nb-ioT is built on cellular mobile networks, consuming only about 180KHz of bandwidth, and can be deployed directly on GSM networks, UMTS networks or LTE networks to reduce It can be deployed directly in GSM network, UMTS network or LTE network to reduce the cost of working deployment enterprise and realize data smoothing technology upgrade. NB-IoT as a new narrowband cellular system communication LPWAN (Low Power Wide Area Network) problem solving solution for students will bring a huge impact of change and innovation to the IoT related industry market.

Four features of NB-IOT

Super coverage: Compared with the existing GSM, the coverage of broadband lte network is improved by 20 dB, and the signal transmission coverage is larger, which can cover the places that cannot be covered by deep underground GSM network.

Ultra-low power consumption: The maximum current consumption is 5uA in PSM mode and about 6mA in idle mode, and according to the simulation data of TR45.820, a 5Wh battery can send 200 bytes of data per day and is expected to last 12.8 years. So it can be used to develop devices for remote areas in high mountain wilderness.

Super connectivity: Some improvements will be provided indoors for coverage, and NB-IoT gains 20dB over the existing network information in the same frequency band, which is equivalent to a 100 times improvement in the ability to cover different areas. For an underground garage, manhole cover where these problems need to be solved by installing relevant data that can be collected from system devices, NB-IoT is more suitable for enterprises using 3G/4G wireless communication modules or 433MHz wireless control devices.

Super low cost: the cheapest module is now less than $30, and will be much cheaper in the future, after a big promotion.

Use of NB-IOT

Nb-iot operates in three modes: discontinuous reception (drx), extended drx (edrx), and power saving mode (psm). The following figure shows the networking process of nb-iot:

Operation-specific AT command logging (UDP ):

Power on/reboot, where the module design is ready for normal start-up.

AT+Nband? Checking the current band information to determine if it corresponds to the module model.

Set the band to 850mhz for nband = 5 telecom modules;

AT+NRB reboot the module.

AT+NBAND? to perform another query of the functional module band information to confirm setting a successful one.

AT+NCONFIG? to query configuration information, mainly including auto-connect enable configuration information, which is enabled by default.

In Cfun? if the module is in full working state, turn on the RF circuit to search for signals. If it returns 0, please confirm if the auto-connect value is true and if the nbiot special SIM card is installed.

AT+CIMI Query IMSI information, if a specific value is returned, the SIM card has been recognized properly.

AT+CSQ query the relevant signal for strength, the first value returned can represent a signal working strength, 0-31 represents there is a signal, the larger the value the stronger the signal, 99 represents the enterprise has no NBIOT network control signal, the second important parameter has not yet started to implement, has been 99.

AT+NUESTATS query module status.

Check whether the module is successfully installed. 1 indicates that the module is successfully installed.

AT+CEREG? to query the network registration status. the second value returns 1 indicates that the network is successfully registered, returns 2 indicates that the network is being registered, and the registration time is related to the signal strength.

AT+CSCON? check the functional module design work connection a state, the second return value represents the management module work life state, 1 represents CONNECT connection state, 0 represents IDLE sleep state, if we have no relevant data information interaction, in the CONNECT state as well as last 20 seconds, after which enter the IDLE state; if the enterprise still exists without through the data environment interaction, after 10 seconds from the IDLE state development into the PSM deep sleep state, at this time the system module is not receiving any economic downlink data, if the teacher needs to downlink transmission network data must be in the CONNECT and IDLE state.

AT+NSOCR = Dgram, 17, 5683, 1 creates udp socket transmission channel, Dgram and 17 are fixed, 5683 indicates the local port number, 1 indicates that downlink data is allowed to be received, up to 7 SOCKET transmission channels can be created, and the return value indicates the signal ID number. To be specified when sending and receiving data.

At nsost = 0, ... , # # # # , 3,303132 send udp data, 0 indicates udp socket channel id, ... # # # # # indicates the port number of the remote server. 3 indicates the number of characters sent (three characters were sent). 303132 represents 012. the return value indicates 3 bytes of data successfully sent from channel 0;

AT+NSONMI:0, 67 message indicates that the module received new data and needs to read it. If not read in time, the next data received, it will not actively report the information; however, it can be read continuously; 0 represents the UDP SOKECT channel and 67 represents 67 bytes of data to be read.

AT+NSORF=0,3 Read information data; 0 represents the UDP SOCKET channel, 3 represents the length of bytes we need to read the relevant data analysis; need to extract from a return value can effectively improve the data 303132, representing the character "012";

AT+NSOCL=0 to close the udp socket transmission channel.

Summary

In recent years, the authors have used Nb-iot related designs for remote acquisition of certain sensor signals in the field. In the current wireless communication mode, 2g-gsm is the most numerous in this field, but there are some problems, such as high power consumption, some distant base stations with bad signals, and the crisis that 2g will be replaced in the future. 4g also has some problems, such as high power consumption and high cost.

In this case, NB-IOT has unique advantages, especially in application scenarios with small data volume. If you have needs in this area, you can use NB-IOT, a new wireless transmission method, and I think it will bring a lot of surprises to everyone.