Synchronization of licensed assisted access long term evolution (laa-lte) over shared spectrum

An apparatus comprising:

• a transmitter configured to transmit wireless transmissions in a plurality of subframes over a shared spectrum;
• a receiver configured to receive wireless signals in the shared spectrum;
• a modem configured to modulate signals to be transmitted and demodulate received signals;
• and
• a processor configured to:
• obtain data to be transmitted over the shared spectrum;
• generate a first reservation message indicating that an initial synchronization message will be retransmitted as a plurality of retransmitted synchronization messages with a predetermined number of subframes between each of the plurality of retransmitted synchronization messages;
• and
• cause the transmitter to transmit the first reservation message and the initial synchronization message over the shared spectrum.

A method comprising:

• wirelessly receiving a first reservation message over a shared spectrum, the first reservation message indicating that an initial synchronization message for data to be transmitted over the shared spectrum in a plurality of subframes will be retransmitted as a plurality of retransmitted synchronization messages with a predetermined number of subframes between each of the plurality of retransmitted synchronization messages;
• receiving a first plurality of synchronization messages over the shared spectrum, the first plurality of synchronization messages including the initial synchronization message and at least one of the plurality of retransmitted synchronization messages;
• and
• determining a timing of the plurality of subframes based on the plurality of synchronization messages.