Reliable Transmission for Remote Device Management (RDM) Protocol in Lighting Control Networks

The Remote Device Management (RDM) protocol is used to manage lighting devices in the lighting control network. RDM provides bi-directional communication between lighting devices based on the modified DMX512 data link so as to perform device discovery, configuration, monitoring, and management of the devices connected through the DMX512 network. However, the RDM protocol does not provide a reliable packet transmission. To overcome this limitation, we propose the two retransmission schemes: sequence-based retransmission, and timer-based retransmission. In the existing RDM protocol, each response packet uses the same Transaction Number (TN) with that of the request packet from the controller. In the proposed schemes, we use TN to identify a lost or error message. For example, if a response packet with a specific TN number does not arrive within a pre-specified time, the controller will retransmit the concerned request message. From the numerical analysis, it is shown that the proposed retransmission schemes can give better reliability than the existing RDM protocol, and the sequence-based and timer-based retransmission schemes provide the different performance, depending on network environments.