Patent ID: 8065580
Filing Date: 2011-11-22
Classification: H04L

Abstract:
1. A method for safe and secure transmission of data messages between at least one transmitting unit and at least one receiving unit in an HVDC transmission installation, wherein each transmitting unit is connected to each receiving unit via at least two connecting channels, the method which comprises: providing each data message with a message counter uniquely identifying that data message, and each transmitting unit sending the data message via all the connecting channels to each receiving unit, thereby calculating the message counter using an incrementation rule that is clocked by a transmission of the data messages, and each receiving unit calculating a comparison counter using the same incrementation rule, clocked by a reception of the data messages; storing, with each transmitting unit, data messages that have already been transmitted in a transmission buffer; comparing, with the receiving unit, the message counter of each received data message with the comparison counter, and, if there is no match between the message counter and the comparison counter or if there is no match within a waiting period after reception of a data message, sending a repeat request to the transmitting unit to send a data message with a message counter corresponding to the comparison counter; upon receiving the repeat request, accessing the transmission buffer with the transmitting unit and sending the data message via all the connecting channels whose message counter corresponds to the comparison counter received by way of the repeat request; and providing at least two transmitting units and sending the same data messages to one another with the same message counters with the at least two transmitting units.