US Patent 9369215 Asynchronous transmission with double wake up

The present invention relates to an apparatus, method and computer program product for controlling reception in an asynchronous operation mode, wherein a transmitter sends an extended preamble sequence of length longer than the maximum length of a wake up message itself plus the maximum length of a gap between wake up messages, such that a receiver turning on during a sequence of wake up commands and not detecting the wake up commands, can be sure to successfully detect a preamble if it tries again a second time a set interval later.