System and method for a robust preamble and transmission delimiting in a switched-carrier transceiver

摘要

A method and system for robust delimiting of transmitted messages in switched-carrier operation in which a preamble precedes each communication message with the preamble comprising symbols transmitted at a rate lower than that of the following data. The lower rate symbols of the preamble significantly increase the probability that the decoder will decode the preamble symbols error free. Communication line control information can be included in the robust preamble, thereby ensuring that line control information is reliably transferred over the communication channel. The first symbol of the preamble can be transmitted at the lower symbol rate and at an increased power level, thereby clearly and reliably delimiting the beginning of a transmission. The end of the communication message can be reliably delimited by sending the first symbol containing only bits from a next cell of information at a lower symbol rate and including an extra bit in that symbol. The extra bit can be set to indicate to a receiver whether the last cell of information has just begun.