Study on the real time communication protocol of LonWorks bus

Starting from the media access control mechanism of the LonWorks bus and based on the principle of collision avoidance and collision resolution, the problem of real time property in the LonTalk protocol is proved, and the MAC arbitration mechanism of LonTalk protocol is improved. A new real time communication protocol is proposed, which resolves the problem that low priority nodes can not obtain bus access authority over a long period of time, because the bus is occupied alternatively by high priority nodes. Experiments show that compared with the previous protocol, when the number of network nodes are more than 10, the new real time communication protocol reduces the maximum delay time of message transmission at least by 72.33% and the network utilization efficiency is enhanced by 100%. The new real time communication protocol is superior to the previous protocol in real time property and confirmation.