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Conference Proceeding

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LPWAN, cellular IoT, latency, QoE, smart cities, vehicular and wireless technologies, quality of service, benchmark testing, density functional theory


Developing low-power wide-area network (LPWAN) solutions that are efficient to adopt, deploy and maintain are vital for smart cities. The poor quality-of-service of unlicensed LPWAN, and the high service cost of LTE-M/NB-IoT are key disadvantages of these technologies. Concatenating unlicensed with licensed LPWANs can overcome these limitations and harness their benefits. However, a concatenated LPWAN architecture will inevitably result in excess latency which may impact users’ quality-of-experience (QoE). To evaluate the real-life feasibility of this system, we first propose a concatenated LPWAN architecture and experimentally measure the statistics of end-to-end (E2E) latencies. The concatenated delay margin is determined by benchmarking the latencies with different LPWAN architecture schemes, namely with unlicensed IoT (standalone LoRa), cellular IoT (standalone LTE-M), and concatenated IoT (LoRa interfaced with LTE-M). Through extensive experimental measurement campaigns of 30,000 data points of E2E latencies, we show that the excess delay due to LPWAN interfacing introduces on average less than 300 milliseconds. With a users’ QoE satisfaction of 95%, we also found that concatenated LPWAN outperforms unlicensed IoT by roughly 1.5 s. Overall, the result suggests that a concatenated LPWAN is technically feasible and offers an affordable alternative for real-world smart city deployment.


From proceedings of Vehicular Technology Conference (VTC2021-Fall), 2021 IEEE 94th.


Faculty of Applied Science & Technology (FAST)


2021 IEEE 94th Vehicular Technology Conference (VTC2021-Fall)

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Peer Reviewed/Refereed Publication


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Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Original Publication Citation

A. Ramoutar, Z. Motamedi and M. Abdulla, "Latency of Concatenating Unlicensed LPWAN with Cellular IoT: An Experimental QoE Study," 2021 IEEE 94th Vehicular Technology Conference (VTC2021-Fall), 2021, pp. 1-6, doi: 10.1109/VTC2021-Fall52928.2021.9625483.


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