Schc-over-sigfox: Performance modeling and evaluation of fragment delivery

Abstract

The Static Context Header Compression and Fragmentation (SCHC) framework enables IPv6 communication over Low-Power Wide-Area Networks (LPWANs), which provide low power consumption and wide area coverage in exchange for low data rates and small packet sizes. SCHC compresses and fragments large packets and defines the ACK-on-Error reliable delivery algorithm to confirm the reception of fragments and make reassembly possible. The ACK-on-Error mechanism may use additional network resources, which are not always available in constrained networks such as the Sigfox LPWAN. Often times in LPWAN deplyoments, poor connectivity conditions, such as high packet loss rates (PLRs), may lead to aborted communications and wasted resources---decisive factors when determining whether to use SCHC in an application. However, since SCHC is a recent standard, there is a lack of knowledge about the impact of the PLR on the required number of uplink messages and the rate of successful SCHC transmissions. This thesis proposes the definition and analysis of the following performance metrics for SCHC: the average number of uplink messages sent per SCHC transmission, and the rate of successful SCHC transmissions. Semi-empirical models are provided for both metrics. It is demonstrated the models provide a good approximation to the metrics, and that these performance metrics are useful for evaluating SCHC ACK-on-Error usage over Sigfox applications, an analysis that can also be extended to other LPWANs.