Although NB-IoT is integrated into the LTE standard, it can be considered as a new air interface and therefore – on the face of it – not fully backward compatible with legacy networks. However, the genius of its design is that it can happily co-exist with GSM, GPRS and LTE technologies without interference and with excellent side-by-side performance.
In fact, there are three main deployment options for NB-IoT within GSM and LTE networks.
GSM is still the dominant mobile technology within many markets, and the significant majority of M2M applications today use GPRS or EDGE for connectivity. Simply by switching a single GSM carrier to handle NB-IoT traffic, operators can ensure a smooth transition to LTE and massive Machine-type Communication (MTC). This deployment approach will accelerate IoT time to market, maximize the benefit of existing infrastructure and future-proof IoT investment.
Alternatively, in LTE networks, NB-IoT can be deployed ‘in-band’ to provide a highly spectrum-efficient and cost-effective deployment. This in-band option sets NB-IoT apart from any other competing LPWAN technology.
The in-band deployment sees NB-IoT as a self-contained element that uses a single physical resource block (PRB) within the network. Furthermore, the NB-IoT carrier can be switched to other network uses if there is no IoT traffic. This capability means the network can intelligently multiplex IoT and LTE traffic on the same spectrum to minimize the total cost of the operation and scale with the volume of MTC traffic.