# Performance Comparison of NB-Fi, Sigfox, and LoRaWAN
## 5 Numerical Results  
We evaluate and compare the performance of NB-Fi, Sigfox, and LoRaWAN using the simulation. We have developed a discrete-event simulator, which implements the described scenarios and evaluates the dependence of PLR, PER, and average delay on the incoming rate \(\lambda\) for various parameters. Figure 10 shows the dependence of PLR and PER on the rate for the Unreliable Transmission of Short Packets Scenario, where the rate is the ratio of the total number of generated packets during the simulation to the simulation time. In this scenario, PLR coincides with PER because frames are transmitted without repetitions or retries and can be lost only due to collisions with other frames. As we can see, in the Sigfox network, PLR and PER are lower than in NB-Fi and LoRaWAN for all rates because of different amounts of control information added in each frame in these technologies. Specifically, to transmit a 64-bit payload, Sigfox sensors transmit 157 bits, LoRaWAN sensors transmit 204 bits, and NB-Fi sensors transmit 256 bits. Therefore, Sigfox frames have the lowest overhead, which means that a frame transmission in Sigfox networks takes up fewer time-frequency resources and, thus, has a lower probability of collision than in NB-Fi and LoRaWAN networks. Note that even though overhead in LoRaWAN frames is lower than in NB-Fi frames, PLR and PER in these networks are almost the same because LoRaWAN and NB-Fi use different modulations (described in Section 3.1). On the one hand, LoRaWAN frames occupy the entire channel during the transmission, while multiple NB-Fi frames can be transmitted simultaneously without collisions on different central frequencies. On the other hand, LoRaWAN frames have lower overhead and, if transmitted with different \(SF\), can be received and decoded simultaneously. Such differences lead to similar values of PLR and PER in LoRaWAN and NB-Fi networks. Figure 11 shows the dependency of PLR on the rate in the Unreliable Transmission of Long Packets Scenario. The LoRaWAN network achieves the lowest PLR because of the lowest overhead. To transmit 48 bytes of payload, LoRaWAN sensors have to transmit only one frame, while Sigfox and NB-Fi sensors have to transmit 4 and 6 frames, respectively. Sigfox and NB-Fi sensors transmit frames in a block with a random delay between frames, which reduces the probability of collision. However, the PLR for block transmissions is much higher than the PLR for single frame transmission because of higher overhead in Sigfox and NB-Fi, and because losses of a single frame lead to the loss of an entire packet. Thus, LoRaWAN is more reliable compared to Sigfox and NB-Fi for transmitting long packets. Figure 12 shows the dependency of PER on the rate in the Unreliable Transmission of Long Packets Scenario. Even though the LoRaWAN network achieves the lowest PLR, its PER is higher than in Sigfox. Since LoRaWAN sensors transmit only one frame without acknowledgments, PLR and PER for LoRaWAN coincide. At the same time, in NB-Fi and Sigfox networks, PER demonstrates how many frames in a block are received unsuccessfully, compared to PLR demonstrating the loss rate of the entire block transmission. Therefore,  
Figure 11: PLR for the unreliable transmission of long packets scenario. Figure 10: PLR and PER in the unreliable transmission of short packets scenario. PER is lower than PLR for NB-Fi and Sigfox. NB-Fi networks demonstrate the highest PER due to the biggest overhead. Note that Figure 11 shows PLR values up to some maximal rate that depends on the technology and the bitrate. For example, the 100 bps Sigfox curve stops at approximately 40 packets/s. With the considered traffic model, when sensors generate new frames only after transmission of the previous ones, at some rate, the network reaches saturation and cannot achieve higher rates: devices generate new frames at the time which is negligible compared with frame durations and inter-frame intervals.