NB-IoT is an enhanced narrowband data transmission protocol designed for IoT devices. The NB-IoT protocol is optimized to deliver lower data rates but with improved security and longer battery life.

In mobile communications, a spectrum or frequency spectrum is a frequency band that mobile carriers can use to operate mobile cellular services. The frequency spectrum is used by mobile providers to connect devices to the mobile network. The mobile phone and cellular towers communicate using frequencies assigned to the mobile operator as part of the overall frequency spectrum they receive. As a result, a frequency spectrum is simply a set of frequencies. As an example, the frequency spectrum 3.4GHz to 3.8GHz, can be used for 5G cellular services. A country's mobile operator can obtain a portion of this frequency spectrum in order to establish its services.

Standalone

Standalone is one of the simplest classifications. When the NB-IoT network has its own spectrum, it means that there are no other networks running on the exact same spectrum. That is why it is called standalone. It will not have interference with anything else, which is really great, but it will require additional radio frequency (RF) modules which increases mobile provider costs.

Guard Band

A guard band is a short frequency range that divides two broader frequency bands. This prevents interference between communication channels that are being utilized at the same time, which would lower the quality of both transmissions.

By taking advantage of that short unused frequency range, providers can try to launch NB-IoT networks and “fill” that gap that is left there intentionally. While there is a possibility of interference, it is smaller than in-band.

In-band

Imagine that provider has 800-900 MHz spectrum allocated for one of its networks. If it decides to provide an NB-IoT network, it can choose to do so by allocating some space within that 800-900 MHz spectrum. That means that such a network would be located in-band as it is within an existing and used frequency. This is the most convenient option for operators because no hardware changes are required - the LTE spectrum is being utilized. This has been implemented by a large number of operators in Europe. However, there is a higher possibility of internal interference and that is a potential issue that must be carefully controlled.

Frequencies

When it comes to frequencies, these are currently used frequencies per region.