Low Latency Communication in U-space System: Comparative Analysis of Push-pull and Publisher-subscriber Protocols

Kurzfassung

In the U-Space framework, effective communication between key entities such as U-Space Service Providers (USSP), Common Information Service Providers (CISP), and drone operators is essential for the safe and efficient management of Unmanned Aerial Vehicle (UAV) operations. Communication latency is a critical factor in this ecosystem, influencing the responsiveness of real-time services. This research addresses the problem of ensuring low-latency communication in U-Space by analyzing two communication protocols, push-pull (REST-API) and publisher-subscriber (AMQP), to assess their impact on latency between interconnected systems. Using a case study on drone detection, the latency during key operational tasks such as conformance monitoring, flight plan confirmation, and transmitting warnings through the USSP system (different message sizes) are examined. The findings show that message interval significantly affects latency, but the message payload size has minimal effect. Also, this study reveals that the REST-API protocol consistently outperforms the AMQP protocol in terms of latency value and its variability under the experimental conditions tested. Moreover, both protocols demonstrate sufficiently low latency to meet EASA´s requirements for drone operations.