Media access control for license-assisted access

A method performed by a base station, comprising:

• performing transmissions on a first communication channel and a second communication channel, wherein the transmissions on the first communication channel are synchronized by a plurality of first subframes, and the transmissions on the second communication channel are synchronized by a plurality of second subframes;
• generating a time shift between the plurality of first subframes and the plurality of second subframes;
• transmitting a request-to-send message over the first communication channel, the request-to-send message indicating that the base station has data to be transmitted to user equipment (UE) over the second communication channel;
• receiving an indication from the UE that the second communication channel is available for use by the base station;
• and
• in response to receiving the indication, transmitting, at a beginning of a next available second subframe after the indication is received, the data to the UE over the second communication channel.

A non-transitory computer-readable medium comprising a computer program code that, when executed by a processor coupled to a base station, causes the base station to perform operations comprising:

• performing transmissions on a first communication channel and a second communication channel, wherein the transmissions on the first communication channel are synchronized by a plurality of first subframes, and the transmissions on the second communication channel are synchronized by a plurality of second subframes;
• generating a time shift between the plurality of first subframes and the plurality of second subframes;
• transmitting a request-to-send message over the first communication channel, the request-to-send message indicating that the base station has data to be transmitted to user equipment (UE) over the second communication channel;
• receiving an indication from the UE that the second communication channel is available for use by the base station;
• and
• in response to receiving the indication, transmitting, at a beginning of a next available second subframe after the indication is received, the data to the UE over the second communication channel.