Scheduling in license assisted access
In one aspect, a wireless device receives a scheduling grant and a grant confirmation signal indicating that a network node has performed a CCA on a carrier and is releasing the carrier for the wireless device. An uplink message is transmitted on the carrier without performing a CCA on the carrier. In another aspect, a wireless device is connected to a first cell and a second cell configured on a carrier requiring an LBT protocol. The wireless device receives configuration messages indicating that downlink transmissions on the second cell are to be scheduled. This can mean self-scheduling for downlink on the second cell and cross-carrier scheduling for uplink on the first cell. The wireless device receives a scheduling grant in the first cell and performs a CCA in the second cell. The wireless device then transmits an uplink message responsive to success of the CCA.
1 . A method performed at a wireless device, the wireless device being connected to a first cell and a second cell, the method comprising:
transmitting an uplink message in the second cell, responsive to receiving a scheduling grant in the first cell; and
receiving downlink data in the second cell, responsive to receiving a scheduling command in the second cell.
2 . The method of claim 1 , the method further comprising, prior to said transmitting and receiving, receiving one or more configuration messages indicating that downlink transmissions on the second cell are to be scheduled using self-scheduling on the second cell and indicating that uplink transmissions on the second cell are to be scheduled using cross-carrier scheduling on the first cell.
3 . The method of claim 1 , wherein the second cell is configured on a carrier where a listen-before-talk (LBT) protocol for transmission is required to be used, the method comprising:
receiving the scheduling grant in the first cell;
in a subframe occurring a predetermined number of subframes after receiving the scheduling grant, performing a clear channel assessment (CCA) in the second cell; and
transmitting the uplink message responsive to success of the CCA.
4 . The method of claim 1 , wherein the second cell is configured on a carrier where a listen-before-talk (LBT) protocol for transmission is required to be used, the method comprising:
receiving the scheduling grant in the first cell;
receiving, after receiving the scheduling grant, a grant confirmation signal indicating that a network node has performed a clear channel assessment (CCA) on the carrier and is releasing the carrier for the wireless device; and
transmitting the uplink message responsive to receiving the scheduling grant and the grant confirmation signal.
5 . The method of claim 4 , wherein the method comprises receiving the grant confirmation signal in, or subsequent to, the subframe before the first scheduled subframe according to the scheduling grant.
6 . A method performed at a network node, the network node serving a first cell and a second cell, the method comprising:
transmitting a scheduling grant to the wireless device in the first cell;
receiving an uplink message from the wireless device in the second cell, according to the transmitted scheduling grant;
transmitting a scheduling command to the wireless device in the second cell; and
transmitting downlink data to the wireless device in the second cell, according to the transmitted scheduling command.
7 . The method of claim 6 , wherein the second cell is configured on a carrier where a listen-before-talk (LBT) protocol for transmission is required to be used.
8 . The method of claim 6 , wherein the method comprises transmitting, to the wireless device, one or more configuration messages indicating that downlink transmissions on the second cell are to be scheduled using self-scheduling on the second cell and indicating that uplink transmissions on the second cell are to be scheduled using cross-carrier scheduling on the first cell.
9 . A wireless device configured to be connectable to a first cell and a second cell, the wireless device comprising:
radio circuitry; and
processing circuitry operatively coupled to the radio circuitry, wherein the processing circuitry is configured to control the wireless device to:
transmit an uplink message in the second cell, responsive to receiving a scheduling grant in the first cell; and
receive downlink data in the second cell, responsive to receiving a scheduling command in the second cell.
10 . The wireless device of claim 9 , wherein the processing circuitry is further configured to control the wireless device to, prior to said transmitting and receiving, receive one or more configuration messages indicating that downlink transmissions on the second cell are to be scheduled using self-scheduling on the second cell and indicating that uplink transmissions on the second cell are to be scheduled using cross-carrier scheduling on the first cell.
11 . The wireless device of claim 9 , wherein the second cell is configured on a carrier where a listen-before-talk (LBT) protocol for transmission is required to be used and wherein the processing circuitry is further configured to control the wireless device to:
receive the scheduling grant in the first cell;
in a subframe occurring a predetermined number of subframes after receiving the scheduling grant, perform a clear channel assessment (CCA) in the second cell; and
transmit the uplink message responsive to success of the CCA.
12 . The wireless device of claim 9 , wherein the second cell is configured on a carrier where a listen-before-talk (LBT) protocol for transmission is required to be used and wherein the processing circuitry is further configured to control the wireless device to:
receive the scheduling grant in the first cell;
receive, after receiving the scheduling grant, a grant confirmation signal indicating that a network node has performed a clear channel assessment (CCA) on the carrier and is releasing the carrier for the wireless device; and
transmit the uplink message responsive to receiving the scheduling grant and the grant confirmation signal.
13 . The wireless device of claim 12 , wherein the processing circuitry is configured to control the wireless device to receive the grant confirmation signal in, or subsequent to, the subframe before the first scheduled subframe according to the scheduling grant.
14 . A network node configured to serve a first cell and a second cell, wherein the network node comprises:
radio circuitry; and
processing circuitry operatively coupled to the radio circuitry, wherein the processing circuitry is configured to control the network node to:
transmit a scheduling grant to the wireless device in the first cell;
receive an uplink message from the wireless device in the second cell, according to the transmitted scheduling grant;
transmit a scheduling command to the wireless device in the second cell; and
transmit downlink data to the wireless device in the second cell, according to the transmitted scheduling command.
15 . The network node of claim 14 , wherein the second cell is configured on a carrier where a listen-before-talk (LBT) protocol for transmission is required to be used.
16 . The network node of claim 14 , wherein the processing circuitry is configured to control the network node to transmit, to the wireless device, one or more configuration messages indicating that downlink transmissions on the second cell are to be scheduled using self-scheduling on the second cell and indicating that uplink transmissions on the second cell are to be scheduled using cross-carrier scheduling on the first cell.