Читать книгу Intelligent Security Management and Control in the IoT - Mohamed-Aymen Chalouf - Страница 40

As its name indicates, NB-IoT is based on signal transmission over a narrow band. In fact, its spectral occupation is only 180 kHz, which is equivalent to an LTE Physical Resource Block (PRB). Because of this, it results in very low flow rates (at most 250 kbit/s), but these are sufficient for the applications for which this protocol is designed.

NB-IoT technology relies on LTE from which it inherits numerous features and mechanisms, especially at the level of physical and MAC layers. It also re-uses the same numerologies, channel coding, interleaving, etc. This has made it possible to reduce, on the one hand, the time needed to specify this standard and, on the other hand, the costs of developing the NB-IoT devices. However, since the bandwidth used is very narrow, modifications were needed to permit the primary objectives of this standard, that is, the massive use of long-range connections at reduced complexity and cost (Flore 2016).