Performance of TCP and UDP over Narrowband Internet of Things (NB-IoT)

NB-IoT extends LTE by low power WAN functionality for IoT applications. Strengths of the standard lie in the already existing infrastructure, an ubiquitous availability, and the low power consumption and costs. NB-IoT supports both TCP and UDP as transport protocols. However, TCP is sensitive to delays and packet losses during data transmission. This affects the commonly used messaging protocol MQTT, as it uses TCP as its underlying transport protocol. In this paper the role of UDP as a possible transport layer protocol for NB-IoT in conjunction with MQTT-SN is discussed and compared to TCP with standard MQTT. Using TCP for a typical NB-IoT application resulted in a packet loss of about 90%, whereas UDP achieved a packet loss of only around 3%. Additionally, the current state of NB-IoT installations in Germany and their functionality are evaluated. Coverage, signal quality and power saving functionality are monitored and analyzed as well.