## 7 Network Performance Analysis: NB-IoT vs. LoRaWAN
### Throughput  
Data transfer technologies, as specified in the 3 GPP documentation, such as multiple-input-multiple-output (MIMO) and carrier aggregation, provide a higher data transfer rate and high-speed packet access networks in LTE. The test results for bidirectional data transfer show the uplink and downlink data throughput in LMS7002M for sending a 44 bytes TCP message. For the in-band mode of operation, a maximum of 1.57 kbps and 1.59 kbps was obtained for the uplink and downlink channels, respectively. It is important  
Figure 9: Round-trip time between the LTE eNB server and client.  
to note that the performance of the network could be improved if a different UE is used and the number of lost packets is reduced. The actual data throughput for NB-IoT is usually a fraction of the theoretical maximum. The category of UE, network cell bandwidth configuration, and mode of transmission play an important role in achieving good NB-IoT network performance. In the case where a single UE is attached to an NB-IoT network, it can make use of the full available link capacity for transmission. The highest signal level is required for high data rate transmission and aspects such as fading, link loss, line of sight, noise and interference from other base stations could degrade the signal level. For sending between 29 and 48 bytes, as shown in Figure 10, the average throughput varied between 115 bps and 264 bps between the UE (192.168.3.2) and the server (192.168.3.1). Figure 11 compares throughput, latency, and bitrate in the uplink and downlink transmissions, for the same payloads. In LoRaWAN, the size of the data sent to and received from the TTN is 16 bytes, with a LoRaWAN overhead of 14 bytes. The size of the LoRa payload is one of the features that determine the transmission time. For a 20 byte LoRaWAN packet, with a separation distance of 3 m between the Pysense node and the Fipy gateway, to prevent saturating the receiver amplifier, an estimated on-air time of 31.024 ms was obtained for an SF of 7, a BW of 125 kHz, a data rate of 5, and an indicative bit rate of 5470 bits/s. As a single channel gateway, when the distance is increased, the transmission time increases, resulting in reduced throughput and an increase in bit error rate.  
As shown in Figure 12, for every transmission window as shown in Figure 13, a maximum data throughput of 264 bits/s is achieved by the UE which is far below the average throughput established between the LTE eNB server and the client server. During periodicping requests of 48 bytes between the UE and the network, an average round trip time (RTT) of 655.84 ms was recorded due to the high repetition rate in the subframes. A high repetition rate was expected in NB-IoT networks where signal propagation is inefficient.  
Figure 10: NB-IoT throughput and latency for data UE–server payloads. Note that the server-to-UE transmissions is a constant value of 15 bytes with a constant DL and UL bitrate of 396 and 436 and a number of transmissions within 3 and 5, respectively.  
Figure 11: NB-IoT downlink and uplink bitrates for in-band modes of operation. NTdl and Ntul are the number of transmissions in the downlink and uplink channels, respectively, while BRdl are Brul is the bitrate in the downlink and uplink channels, respectively. In the event of retransmissions, the latency increases, as shown in the Ntul spikes between 40 and 48 bytes of data payload in Figure 10.  
Figure 12: Average throughput between the LTE eNB server and MME client. Maximum and minimum throughput of 308 and 45 bytes, respectively, for the round-trip time in Figure 9.  
Figure 13: NB-IoT data throughput for successful interval transmissions for a maximum of 7 packets/s. Retransmissions (rtx 1, 2 and 2) occurred in a few of the transmissions’ windows and courses’ spikes in the number of packets that increased the maximum number of packets to 9 packets/s. At 50 bytes (rtx3) of data payload, the successful transmission rate decreased and, in most cases, resulted in unsuccessful transmission.