Several issues that must be understood about the NB-IoT protocol

The cellular-based Narrow Band Internet of Things (NB-IoT) has become an important branch of the Internet of Everything. Unlike the standard LTE that uses all 10MHz or 20MHz bandwidth, NB-IoT is built on the cellular network and consumes only about 180KHz of bandwidth. It can be directly deployed on the GSM network, UMTS network or LTE network to reduce deployment costs and achieve smooth upgrades.

This more simplified standard provides very low power consumption for connected devices. In addition, it can be deployed as a software overlay on any LTE network. NB-IoT's resource blocks can fit neatly into standard LTE channels or guard bands. It can also fit into standard GSM channels when operators re-divide their older 2G spectrum. Modulation uses OFDMA downlink and SC-FDMA uplink.

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1. What NB-IoT frequency bands are available for use by domestic operators?

2. What vertical application scenarios are suitable for NB-IoT?

3. What is the deployment cost of NB-IoT vertical application areas?

ZTE mentioned in "Pre5G Building the Bridge to 5G" that the cost of NB-IoT modules is $5-10, and the cost of chipsets is about $1-2. The market expectation for the cost of NB-IoT modules should be <$5. What will the specific manufacturer's sales price be? It is still unknown. However, having NB-IoT modules alone is not enough, because NB-IoT is a licensed frequency band. To access the operator's network, a SIM card or eSIM (Embedded SIM) is also required. Each NB-IoT module will also have traffic or service fees.

• Operator charges: one is charged by traffic, the other is charged by message, and the trend is lower than GPRS charges
• Chip price: lower than 2G main chip, reasonable expected price $1
• Module price: lower than GPRS module price, reasonable expected price $2
• Terminal price: Pricing based on actual functions
• Maintenance cost: much lower than the existing network maintenance cost
• Subsidy policy: In the early stage, operators will provide large operating subsidies

4. What certifications do NB-IoT products require?

A network access license is required in each country. The SIM card and IMEI number need to be bound.

5. What is the technical comparison between NB-IoT and other low-power wide area networks?

6. What are the deployment methods of NB-IoT?

NB-IoT supports three different deployment modes: independent deployment, protection band deployment, and in-band deployment.

• Independent deployment: A separate frequency band can be used, which is suitable for refarming the GSM frequency band.
• Guard band deployment: It can utilize the unused frequency bands at the edge of the LTE system.
• In-band deployment: Any resource block in the middle of the LTE carrier can be used.

7. What is the coverage range of NB-IoT base stations?

NB-IoT has a 20dB gain improvement over LTE and GPRS base stations, and is expected to cover underground garages, basements, underground pipelines and other places where signals are difficult to reach. According to simulation test data, in standalone deployment mode, NB-IoT coverage can reach 164dB, and in-band deployment and protection band deployment are still under simulation testing.

8. What is the uplink and downlink transmission rate of NB-IoT?

The NB-IoT radio frequency bandwidth is 200kHz.

Downlink rate: greater than 160kbps, less than 250kbps. Uplink rate: greater than 160kbps, less than 250kbps (Multi-tone)/200kbps (Single-tone).

9. Does NB-IoT sleep-wake mode affect battery life?

The working time given by NB-IoT is currently based on simulation data, without considering the battery itself and environmental factors, such as battery self-discharge and aging, high and low temperature environment effects, etc. In actual use, the battery power supply time needs to be comprehensively evaluated according to the actual situation. NB-IoT uses a power saving solution of sleep wake-up. When the battery is awakened during sleep, it will receive a transient strong current, which will greatly affect the battery life. Meter reading applications usually use lithium thionyl chloride (Li/SOCl2) batteries with supercapacitors. Consumer electronics and other applications are usually powered by polymer lithium batteries.

10. What is the network latency of NB-IoT?

NB-IoT allows a latency of about 10s, but can support lower latency, such as around 6s, in a maximum coupling loss environment.