NB-IoT, Narrow Band Internet of Things. General information, technology features

Good day to all!

It describes the NB-IoT in terms of end devices and ordinary users. Since there is a lot of information, I will break it into several parts. In this part we will discuss general information, features of the NB-IoT technology and the state at the beginning of 2019.

NB-IoT (Narrow Band Internet of Things) is an LTE-based cellular technology designed for fixed devices with low data transfer rates and low power consumption. The GSM Association promises that the NB-IoT devices will be cheap and (under certain conditions) will be able to work from conventional batteries for up to 10 years. Interestingly, the association also describes NB-IoT as a technology created in a short time in response to user requests and competition from similar proprietary solutions:
https://www.gsma.com/iot/wp-content/uploads/2018/04 /NB-IoT_Deployment_Guide_v2_5Apr2018.pdf

NB-IoT refers to the so-called CIoT, Cellular IoT (3GPP terminology) or MIoT, Mobile IoT (GSMA terminology) and is promoted by cellular operators and manufacturers of the corresponding equipment. Narrow Band (Narrow Band) called this type of communication compared to the "traditional" LTE, which uses significantly wider frequency bands (3, 5, 10, 15, 20 MHz). The width of the NB-IoT frequency channel is 200 kHz.

A few words about CIoT (MIoT)

Currently, CIoT (MIoT) is branched into 2 directions: NB-IoT and LTE-M (also called eMTC or LTE Cat.M).

NB-IoT is oriented more towards fixed (stationary) devices, since in this mode automatic handover is not supported. When moving to another cell, the NB-IoT device will have to register again on the network. Thus, NB-IoT is intended primarily for applications such as automatic collection of readings from meters, sensors, remote control of street lighting, etc. Unlike NB-IoT, another CIoT “branch” - LTE-M - supports both switching between cells and provides several times higher transmit / receive rates.

Advantages and disadvantages of NB-IoT

As usual, the advantages and disadvantages are directly related to each other: if somewhere has arrived, then somewhere has gone. Here I will simply list them with a few comments, and we will discuss the details later.

Advantages of NB-IoT

• Low power consumption of terminal devices (when using power saving modes PSM and eDRX)
• Large power line communication budget (GSMA called the figure 164 dB)
• Theoretically global coverage
• Theoretically low cost of modems (modules) and communication services

Disadvantages of NB-IoT

• Long communication delays are possible when using power saving modes. The fact is that the terminal device, being in power saving modes, is inaccessible from the network (application server). The maximum delay when using the eDRX mode is determined by the maximum eDRX period, which is 10485.76 seconds, i.e. almost 3 hours. The maximum delay when using the PSM mode is determined by the maximum time the device is in the PSM mode — 9920 hours, which is 413 days and 8 hours, i.e. more than 1 year! Power saving modes are discussed in detail in the next section.
• Lack of mobility support
• Low data reception and transmission rates (see below)

Development of NB-IoT in the world and the Russian Federation

Interestingly, some countries / regions prefer the priority development of NB-IoT (Europe, China, Russia), others - LTE-M (USA, Canada). But in general, it is believed that in the near future, both standards will be deployed globally.

Here is a map and commercial launches of CIoT networks according to GSMA:

Map of the development of NB-IoT and LTE-M networks in the World
Data on commercial launches of NB-IoT and LTE-M networks in the World

Russia on the GSMA map for some reason still remains in the gray zone. Or waiting for confirmation of commercial launches?

Nevertheless, here are some interesting press releases from Russian cellular operators regarding NB-IoT:
MTS launches a special NB-IoT tariff for the Internet of things
MTS has released an NB-IoT sim card for the Internet of things
MTS has built Russia's first federal network NB- IoT for the Internet of Things
MegaFon introduced the first in Russia tariff for managing NB-IoT devices
Beeline presented the first in Russia hybrid network for IoT
Beeline began testing IoT solutions in Moscow
Tele2, Ericsson and Rostelecom tested NB-IoT for housing and communal services in Moscow and St. Petersburg

When this article was written, the information came that MTS had already launched its NB-IoT network into commercial operation!

Data rates in NB-IoT

If only one NB-IoT variant - Category NB1 was defined in the specifications of 3GPP Release 13, then in the specifications of 3GPP Release 14 2 variants appeared: Category NB1 and NB2. Category NB2 is faster. For comparison of the capabilities of NB1 and NB2, Table 1 shows the maximum sizes of transport blocks for reception and transmission in accordance with the 3GPP 36.306 Release 14 specification:

Qualcomm, in the specification of the MDM9206 chip (used in the N20 module ), lists the following transmission speeds in Cat mode. NB1: reception (DL) - 20 kbps, transmission (UL) - 60 kbps:
https://www.qualcomm.com/products/mdm9206-iot-modem

Similar results for NB1 are given by colleagues from MTS, mentioning that for category NB2 the maximum transmission / reception rate will be more than 100 kbps:
https://habr.com/company/ru_mts/blog/430496/

But, as far as I understand, we are talking about the physical speed in the communication channel, respectively, the actual data transfer rate will be much lower. Unfortunately, at the moment I have no experimental data on the maximum transmission rate in the NB-IoT mode.

Frequency ranges for NB-IoT in the Russian Federation

According to the decision of the State Committee on Radio Frequency Commission of December 28, 2017 (protocol No. 17-44), https://digital.gov.ru/ru/documents/5875/ , the following frequency bands in the territory of the Russian Federation can be used for NB-IoT:
453–457, 4 MHz,
463–467.4 MHz,
791–820 MHz,
832–862 MHz,
880–890 MHz,
890–915 MHz,
925–935 MHz,
935–960 MHz,
1710–1785 MHz,
1805–1880 MHz,
1920–1980 MHz,
2110–2170 MHz,
2500–2570 MHz,
2620–2690 MHz.

With a few exceptions:

... exclusion of the operation of the RES in the NB-IoT mode in the radio frequency bands 453-453.15 MHz and 463-463.15 MHz in the territory of Moscow and the Moscow Region

It seems that the SCR simply allowed the NB-IoT to be deployed in all frequency ranges in which the deployment of any cellular networks was ever allowed ...
But which of them will be used first?

According to data obtained from different sources, at the beginning of 2019 for NB-IoT (in test mode) in Russia, the following frequency bands are used:

• Megaphone - B8 band (UL: 880-915 MHz, DL: 925-960 MHz)
• MTS, Beeline, Tele2 - B20 bands (UL: 832-862 MHz, DL: 791-821 MHz) and B3 (UL: 1710-1785 MHz, DL: 1805-1880 MHz)

This data completely coincides with the European frequency ranges, which are given in the NB-IoT Deployment Guide to Basic Feature set Requirements. Version 2.0 dated April 5, 2018

Thus, at the beginning of 2019, the current NB-IoT ranges for the Russian Federation can be considered: B20, B8 and B3.

According to some market participants, the NB-IoT will be deployed primarily in the sub-gigahertz frequency bands (B20, B8) to provide the best coverage.

Will it be possible to send / receive TCP / UDP packets in NB-IoT in the same way as in GSM, for example?

Can! At least we tried to send and receive TCP / UDP packets using the N21 and N20 modules , and everything worked out.

Will it be possible to send and receive SMS in NB-IoT?

According to the GSM association document mentioned above, as of April 2018, the SMS function was not included in the minimum set of requirements recommended by the GSMA for implementation in NB-IoT networks. According to a survey conducted by GSMA, only some of the operators plan to implement SMS in the NB-IoT mode in the future. Nevertheless, the study of this issue continues.

MegaFon and MTS representatives confirmed that the SMS function in the NB-IoT mode is likely to become available in their networks in the future.

PS The article does not claim to absolute truth and may contain inaccuracies. If you notice inaccuracies, want to share insider information or just give your opinion - welcome to the comments!

Continued: NB-IoT, Narrow Band Internet of Things. Power saving modes and control commands.