Throughput analysis of p-CSMA based LonTalk protocols for building management systems

We analyse the feasibility of using a building management system (BMS) with multimedia communications over an automation network, focusing our attention on the requirements and limitations for digital video transmission. First, we address the communications requirements of BMS video information, selecting a quarter of intermediate format (QCIF). We choose an 1.25 Mbit/s LonTalk bus as the BMS communications subnetwork. The LonTalk medium access delay is analysed. Performance figures are obtained for a case study scenario, and we conclude that the selected bus fits our requirements.