Lower Bound for the Number of Accommodable End-devices in LPWAN with Multiple Interferences

Abstract

Coverage evaluation is necessary to derive the number of end devices that can be accommodated to wireless networks, and it is an evaluation metric for wireless network, such as low power wide area networks (LPWANs). In traditional analysis, conditional coverage probabilities are derived when the desired LoRa signal does not conflict with an interference signal and when the desired LoRa signal conflicts with a single interference signal. However, in the case that network load is 0.45, a probability of interference occurrence from two EDs is approximately 14.7%, whereas the probability from one EDs is approximately 36.1%. The difference between probabilities is approximately 20%, and we believe that it cannot be ignored on derivation of the number of accommodable end devices. In this study, we derive and evaluate the theoretical values of the conditional coverage probability when two interference signals arrive. Based on the probability, we derive a lower bound on the number of end devices that can be accommodated. Numerical examples are shown to validate the effectiveness of the derived lower bound on the number of accommodable end devices.