Development of a loopback-based validation framework for 5G layer-1 eCPRI fronthaul

Abstract

One of the most important aspects of software engineering, including telecommunications, is validation and verification. Therefore, this thesis focuses on validating 5G Layer-1 fronthaul communication, i.e., the link between the main processing part of the base station (distributed unit) and its radio part (radio unit), using the enhanced Common Public Radio Interface (eCPRI) protocol. The aim of the work was to develop a validation framework based on the loopback mechanism, which allows outgoing packets to be immediately returned to another port of the same unit. This framework provides an alternative to the existing approach, in which packet data is captured before transmission and which has limitations in terms of coverage and versatility. The scope of development was limited to outgoing eCPRI traffic on the distributed unit side for a limited number of eCPRI message types. The framework was implemented as a standalone C++ class and validated by comparing loopback-captured packets with those extracted from the existing internal capture mechanism. Within the selected scope, the results demonstrated a 100% match, with no missed or corrupted packets. In addition, the functionality was expanded with timing-related information extraction, which was verified against reference values calculated from the eCPRI timing header. The results indicate that the developed framework can be used for both packet-level and timing-related validation within the defined scope and provides a basis for further extensions.