  The broad range of requirements of Internet of Things applications has lead
to the development of several dedicated communication technologies, each
tailored to meet a specific feature set. A solution combining different
wireless technologies in one device, can overcome the disadvantages of any
individual technology. The design of such Multiple Radio Access Technology
solutions based on the diverse characteristics of the technologies offers
interesting opportunities. In this work we analyze the potential of combining
LoRaWAN and NB-IoT in a Multi-RAT solution for IoT. To that end we evaluate key
IoT node requirements in function of payload size and link quality: (1) energy
efficiency, (2) coverage, (3) payload size, (4) latency performance, (5)
Quality of Service, and (6) cost efficiency. Our theoretical assessment and
experimental validation of these IoT features show the merits of a Multi-RAT
solution. Notably, energy consumption in use cases with only sporadic large
payload requirements, can be improved by a factor of at least 4 with respect to
either single-mode technologies. Moreover, latency-critical messages can get
delivered on time and coverage can be extended elegantly where needed.
