## 6 Conclusions and Future Work  
In this paper, the design and implementation of a lightweight heterogenous multi-homed network (LHM-N) model for diverse smart city applications is carried out. The LHM-N model addresses dense heterogeneity network challenges, such as the difficulties in the management of LPWANs coexistence, interference, spectrum insufficiency, QoS, and scalability issues, in a smart cities' scenario. The solution model advocates the enabling of smartness in the diverse IoT application domains, such as transport and mobility, health care, natural resources, electricity and energy, homes and buildings, commerce and retail, society and workplace, industry, agriculture, and the environment. A receiver diversity-based TCM technique, RX-TCM, is implemented on the LHM-N model for the IoT application solution suitable for a smart city ecosystem. In addition, the paper integrates a manageable license-free LPWAN coexistence with 5G private and public cellular networks in the LHM-N model. This provides a very cost-effective solution model in a heterogeneous dense smart city environment. Further, a 5G reduced capability (RedCap) IoT device is integrated into the (LHM-N) model for supporting high-bandwidth smart city application solutions. Furthermore, the optimization of the PHY layer protocol of the 5G reduced capability (RedCap) IoT device to operate comparatively with LPWAN in terms of signal-to-noise ratio (SNR) symbol energy is carried out. The 5G RedCap performs optimally at medium to high data throughput with low latency in the LHM-N model.  
Furthermore, the MATLAB simulation results validate the performance of the LHM-N model with a lower error rate and lower transmission delay compared to the conventional QAM protocol. The 5G RedCap protocol optimization performs five times better than the conventional QAM protocol in terms of data throughput without an energy cost expense for medium- to high-bandwidth industrial IoT (IIoT) applications. In addition, the proposed packet-size forwarding engine (PSFE) algorithm outperforms TCP Reno and TCP Cubic algorithms with very low protocol overhead. Finally, the minimal protocol overhead in the PSFE algorithm can be attributed to enabling congestion avoidance in packet-forwarding transmission.  
Regarding future work, the authors aim to carry out coverage and energy/complexity evaluations of the developed LHM-N model compared with conventional LPWANs, such as LTE-M (eMTC), in a smart city scenario. This is to establish the nearness of the LHM-N model features to features of the LPWAN in a smart city scenario.  
Author Contributions: Conceptualization, E.U.O.; methodology, E.U.O.; software, E.U.O. and A.M.K.; validation, E.U.O., A.M.A.-M. and A.M.K.; formal analysis, E.U.O., A.M.A.-M. and A.M.K.; investigation, E.U.O.; resources, A.M.A.-M. and A.M.K.; data curation, E.U.O.; writing--original draft preparation, E.U.O.; writing--review and editing, A.M.A.-M. and A.M.K.; visualization, E.U.O.; supervision, A.M.A.-M. and A.M.K.; project administration, E.U.O., A.M.A.-M. and A.M.K.; funding acquisition, A.M.A.-M. and A.M.K. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors acknowledge the resources provided by CSIR, Pretoria, and FSATI at Tshwane University of Technology, Pretoria, in support of this research.  
The authors declare no conflict of interest.