摘要:
An updateable message encoder/transmitter (100) has a processor (109) for encoding messages and message updates. A message includes an origination time (191), a version number (410) and an update lifetime indicator (424), and a message update includes the origination time (191) and the version number. A transmitter (120) broadcasts the message and the message update message receiver/decoder (130) receives the message and the message update, a processor (212) processes the message to determine when the message update is being received. The processor checks the update lifetime indicator of the message indicated by the message update to determine if the message to which the message update is intended can be updated. A comparator compares the origination time of the message with the origination time of the message update to determine if the message update is an out-of-sequence message update.