Abstract:
Over the past few years, we have witnessed an
explosive increase in the number of Long Range Wide Area
Network (LoRaWAN) devices, primarily because LoRaWAN
offers attractive features such as long-range, low-power, and lowcost communications. However, the scalability of LoRaWAN is a
major concern, which in particular depends on spreading factor
(SF) allocation schemes. Primarily, SFs are assigned based on
distance from the gateway, using equal-interval-based (EIB) and
equal-area-based (EAB) SF allocation schemes. In this paper, we
have proposed an SNR based SF allocation scheme to improve
the scalability of LoRaWAN. We have introduced two different
algorithms for the proposed scheme. Using stochastic-geometry,
an analytical framework is developed for both the algorithms,
and the expressions are derived for the packet success probability
(PSP) under the co-SF interference scenario. In addition, the
impact of an inter-SF interference on the PSP performance is
analyzed by simulations. The proposed algorithms are compared
with the EIB and EAB SF allocation schemes, and it is shown
that the proposed algorithms perform better than the other two
schemes. We have also analyzed the impact of end device (ED)
density, packet size, and cell-radius on the LoRaWAN scalability.
Moreover, we have performed real-time experiments to prove the
applicability of the presented work in practical scenarios.
