Enhanced uplink spectrum sharing

1 . A method performed by a second base station for sharing a first air interface resource allocated to a first cell that uses a first radio access technology (RAT) and is implemented by a first base station, with a second cell that uses a second RAT and is implemented by the second base station, the method comprising:

communicating, to a user equipment (UE) a second air interface resource configuration for a second air interface resource allocated to the second cell that uses the second RAT;

receiving, from the first base station, a first air interface resource configuration for the first air interface resource allocated to the first cell that uses the first RAT, the first air interface resource configuration being different from the second air interface resource configuration, and the first cell at least partially overlapping the second cell;

communicating, to the UE, the first air interface resource configuration;

receiving, from the first base station, a low-utilization indication for the first air interface resource;

based on receiving the low-utilization indication, directing the UE to utilize the first air interface resource for transmitting uplink communications to the second base station using the second RAT; and

receiving, from the UE, a first uplink communication using the first air interface resource and the second RAT.

2 . The method as recited in claim 1 , wherein the first air interface resource configuration for the first air interface resource is a first physical uplink control channel (PUCCH) air interface resource configuration for a first PUCCH resource, and wherein the second air interface resource configuration for the second air interface resource is a second PUCCH resource configuration for a second PUCCH resource.

3 . The method as recited in claim 2 , wherein receiving the low-utilization indication for the first PUCCH resource further comprises:

receiving a toggle field that indicates an availability of the first PUCCH resource.

4 . The method as recited in claim 1 , further comprising:

receiving, from the UE, a second uplink communication using the second air interface resource and the second RAT.

5 . The method as recited in claim 1 , wherein receiving the first uplink communication further comprises:

receiving control-plane information from the UE; or

receiving user-plane data from the UE.

6 . The method as recited in claim 1 , wherein receiving the first uplink communication further comprises:

receiving, as control-plane information, an acknowledge (ACK) or a negative-acknowledge (NACK) for a downlink communication transmitted by the second base station to the UE using the second RAT.

7 . The method as recited in claim 1 , wherein communicating the second air interface resource configuration comprises communicating at least one of:

a start time to begin using the first air interface resource; or

a stop time to cease using the first air interface resource.

8 . The method as recited in claim 1 , wherein communicating, to the UE, the first air interface resource configuration comprises:

directing the UE to refrain from using the first air interface resource until receiving a notification from the second base station.

9 . The method as recited in claim 1 , wherein the first air interface resource configuration specifies one or more different air interface resource configuration parameters than the second air interface resource configuration, the one or more different air interface resource configuration parameters comprising one or more of:

a frequency partition;

a resource block allocation;

a PUCCH region;

a reference signal structure; or

a coding scheme.

10 . A method performed by a user equipment (UE) for using a first air interface resource allocated to a first cell that uses a first radio access technology (RAT) and is implemented by a first base station, to communicate via a second cell that uses a second RAT and is implemented by a second base station, the method comprising:

receiving, from the second base station, a second air interface resource configuration for a second air interface resource allocated to the second cell that uses the second RAT;

receiving, from the second base station, a first air interface resource configuration for a first air interface resource allocated to the first cell that uses the first RAT, with the first air interface resource configuration being different from the second air interface resource configuration, and with the first cell at least partially overlapping the second cell;

receiving, from the second base station, an indication to utilize the first air interface resource for uplink communications to the second base station using the second RAT; and

transmitting a first uplink communication to the second base station using the first air interface resource and the second RAT.

11 . The method as recited in claim 10 , wherein the first air interface resource configuration for the first air interface resource is a first physical uplink control channel (PUCCH) air interface resource configuration for a first PUCCH resource, and wherein the second air interface resource configuration for the second air interface resource is a second PUCCH resource configuration for a second PUCCH resource.

12 . The method as recited in claim 11 , wherein receiving the indication comprises at least one of:

receiving a start time to begin using the first PUCCH resource;

receiving a stop time to cease using the first PUCCH resource; or

receiving a toggle field that indicates an availability of the first PUCCH resource.

13 . The method as recited in claim 10 , further comprising:

transmitting, to the second base station, a second uplink communication using the second air interface resource and the second RAT.

14 . The method as recited in claim 10 , wherein transmitting the first uplink communication further comprises:

encoding the first uplink communication using identity information associated with the second base station.

15 . A second base station comprising:

a processor; and

computer-readable storage media comprising instructions, responsive to execution by the processor, direct the second base station to:

communicate, to a user equipment (UE) a second air interface resource configuration for a second air interface resource allocated to a second cell that uses a second radio access technology (RAT) and is implemented by the second base station;

receive, from a first base station, a first air interface resource configuration for a first air interface resource allocated to a first cell that uses a first RAT and is implemented by the first base station, with the first air interface resource configuration being different from the second air interface resource configuration, and with the first cell at least partially overlapping the second cell;

communicate, to the UE, the first air interface resource configuration;

receive, from the first base station, a low-utilization indication for the first air interface resource;

based on the reception of the low-utilization indication, direct the UE to utilize the first air interface resource for transmitting uplink communications to the base station using the second RAT; and

receive, from the UE, a first uplink communication using the first air interface resource and the second RAT.

16 . The second base station of claim 15 , wherein the first air interface resource configuration for the first air interface resource is a first physical uplink control channel (PUCCH) air interface resource configuration for a first PUCCH resource, and wherein the second air interface resource configuration for the second air interface resource is a second PUCCH resource configuration for a second PUCCH resource.