License assisted listen-before-talk

A method of operation of a wireless device in a wireless system in which the wireless device transmits and/or receives in both a licensed spectrum and an unlicensed spectrum, comprising:

• attempting to detect a busy indication transmitted in the licensed spectrum, the busy indication being an indication that another wireless device is transmitting in the unlicensed spectrum;
• and
• determining whether to transmit in the unlicensed spectrum based on whether the wireless device has detected a busy indication transmitted in the licensed spectrum, wherein determining whether to transmit in the unlicensed spectrum based on whether the wireless device has detected a busy indication transmitted in the licensed spectrum comprises:
• determining that the wireless device has detected a busy indication transmitted in the licensed spectrum;
• determining that the detected busy indication is a busy indication transmitted in the licensed spectrum by another wireless device;
• and
• determining whether the wireless device has also detected a busy indication transmitted in the licensed spectrum by a serving radio access node of the wireless device;
• wherein the wireless device determines to transmit in the unlicensed spectrum upon determining that the wireless device has not also detected a busy indication transmitted in the licensed spectrum by the serving radio access node of the wireless device.

A method of operation of a wireless device in a wireless system in which the wireless device transmits and/or receives in both a licensed spectrum and an unlicensed spectrum, comprising:

• attempting to detect a busy indication transmitted in the licensed spectrum, the busy indication being an indication that another wireless device is transmitting in the unlicensed spectrum;
• and
• determining whether to transmit in the unlicensed spectrum based on whether the wireless device has detected a busy indication transmitted in the licensed spectrum, wherein determining whether to transmit in the unlicensed spectrum based on whether the wireless device has detected a busy indication transmitted in the licensed spectrum comprises:
• determining that the wireless device has detected a busy indication transmitted in the licensed spectrum;
• determining that the detected busy indication is a busy indication transmitted in the licensed spectrum by another wireless device;
• decoding the busy indication to obtain an identifier of an intended recipient of the transmission in the unlicensed spectrum by the other wireless device;
• and
• determining whether the intended recipient is a serving radio access node of the wireless device;
• wherein the wireless device determines to transmit in the unlicensed spectrum upon determining that the intended recipient is not the serving radio access node of the wireless device.

A wireless device for a wireless system in which the wireless device transmits and/or receives in both a licensed spectrum and an unlicensed spectrum, comprising:

• a transceiver;
• at least one processor;
• and
• memory comprising instructions executable by the at least one processor whereby the wireless device is operable to:
• attempt to detect a busy indication transmitted in the licensed spectrum, the busy indication being an indication that another wireless device is transmitting in the unlicensed spectrum;
• determine whether to transmit in the unlicensed spectrum based on whether the wireless device has detected a busy indication transmitted in the licensed spectrum;
• and
• upon determining to transmit in the unlicensed spectrum, transmit a busy indication in an uplink channel in an uplink spectrum of a cellular communications network, the cellular communications network comprising a serving radio access node.

A radio access node for a wireless system, comprising:

• at least one radio unit;
• at least one processor;
• and
• memory comprising instructions executable by the at least one processor whereby the radio access node is operable to:
• receive a first busy indication in an uplink channel in an uplink spectrum of a wireless network from a wireless device, the first busy indication being an indication that the wireless device is transmitting in an unlicensed spectrum;
• and
• transmit a second busy indication in a licensed spectrum indication in response to receiving the first busy indication, the second busy indication being an indication that the wireless device is transmitting in an unlicensed spectrum.