## 9 Conclusions  
In this paper, we presented the sustainable opportunities that licensed and unlicensed LPWANs could offer with regard to IoT development in developing countries and compared LoRaWAN and NB-IoT in terms of power consumption, security, latency, and throughput perspectives. With Nigeria as a case study, we discussed the practical challenges and opportunities of deploying LoRaWAN and NB-IoT technologies. The real-world performance/power measurements, as presented herein, show that NB-IoT and LoRaWAN have the potential to drive the realisation of SDGs in developing countries through, for example, the provision of effective asset tracking and environmental monitoring solutions. However, the increased energy efficiency of LoRaWAN suggests that when the QoS requirements of a licensed solution are not required, LoRaWANs could offer savings in a like-for-like deployment, albeit at a reduced QoS. However, the test results proved that on average, NB-IoT could outperform LoRaWAN in terms of data throughput, latency, and security. On the other hand, the roles that the current GSM and LTE MNOs will play to facilitate licensed IoT penetration in developing countries is considered, specifically in the context of challenges in reaching some locations were also presented. The important features of NB-IoT 3 GPP standard releases 14, 15, and 16 were discussed; while the performance of release 13 was demonstrated in our testbed, we showed the specific performance of the testbed on power consumption, data throughput, latency, and security of the network as four network features for facilitating NB-IoT for other use-cases. New experimentation capabilities, as introduced in our testbed, allowed the LoRaWAN integration and present evidence of spectrum needs, power utilisation, latency, data rate, and security to guide deployment decisions. These are essential in determining the reliability of LPWAN, and understanding how LPWAN options may help to meet service requirements such as NB-IoT, which guarantees data delivery but at higher energy costs. In contrast, the duty cycle regulations and ISM signal interference affects the reliability and maximum per-device throughput of LoRaWAN, with the benefits of consuming less energy and being cheaper to deploy. _Potential Benefits and Drawbacks of Integrated LPWANs_  
* Wider Range of Applications--When multiple LPWANs such as LoRaWAN and NB-IoT are supported and integrated on a single IoT device, the effective coverage area will be that of the LoRaWAN and NB-IoT. Though switching between multiple technologies causes an increase in energy consumption due to the cost of the IoT modules and computational overhead increase, it has the potential to rapidly increase the IoT footprint in developing countries as the networks can be extended using a single gateway. IoT devices can dynamically switch between the LPWANs available. The optimisation of the circuit and components' design could improve the cost, energy, and data overhead challenges. * Improved Reliability--An integrated LoRaWAN and NB-IoT network guarantees message delivery. This means a more robust and intelligent network that can periodically switch technology types based on message sizes and QoS requirements. NB-IoT is for more frequent transmissions while LoRaWAN is for less sensitive and periodic data transmissions. * Improved Latency--The availability of more than one LPWAN option for message delivery increases the opportunity to spread IoT data over multiple technologies based on the criticality of the application, payload size, and power source. Dependingon the application, variable message sizes can be efficiently and reliably sent. For instance, indoor transmissions can be performed using NB-IoT [81]. * Reduced Cost--The cost of deploying NB-IoT is generally higher than LoRaWAN. NB-IoT operates in licensed spectrum, and the costs of acquiring the spectrum and base stations limits the deployment of private cellular networks.