Design and Evaluation of a Bidirectional Communication Channel for O-RAN Digital Twins

The Open RAN paradigm enables programmability and automation through openness and disaggregation, but introduces new challenges in terms of reliability, observability, and validation prior to field deployment. Digital Twins (DTs) can address these challenges by providing a controlled and synchronized representation of the real system, enabling planning, optimization, validation, and security-oriented analyses. However, this paradigm requires an efficient bidirectional communication channel, as the fidelity of the DT depends on continuous synchronization. In this paper, we design and implement a bidirectional communication channel for Real World-DT synchronization based on brokerless technologies and we provide an experimental assessment of Zenoh and ZeroMQ as enabling technologies. Using a reproducible pipeline, we assess the performance in terms of latency, jitter, round-trip time, throughput for different payload sizes ranging from 100B to 1MB and in both Real World-to-DT and DT-to-Real World directions. Results show sub-millisecond mean latency for payloads up to 10KB and only a few milliseconds for larger messages. When placed in context with prior MQTT-based Real World–DT systems, the measured values suggest that brokerless communication is a promising alternative for reducing application-level synchronization delay.