Communication of cell configuration parameters of an unlicensed cell

1. A method comprising:

receiving, by a first base station from a second base station, cell configuration parameters of one or more cells of the second base station, the cell configuration parameters comprising:

at least one first information element (IE) indicating a first identifier of a first cell of the one or more cells;

at least one second IE indicating that the first cell is an unlicensed cell;

at least one third IE indicating a radio frequency channel number of the unlicensed cell; and

at least one fourth IE indicating a bandwidth of the unlicensed cell; and

sending, to the second base station, a request message for adding the second base station as a secondary base station for a wireless device after receiving the cell configuration parameters.

2. The method of claim 1 , wherein the cell configuration parameters further indicate at least one of:

a downlink frequency;

an uplink frequency;

a downlink bandwidth; or

an uplink bandwidth.

3. The method of claim 1 , wherein the cell configuration parameters further indicate at least one of:

an unlicensed cell subframe configuration;

a subframe start position;

a cross carrier scheduling configuration of an unlicensed uplink;

a physical downlink control channel (PDCCH) configuration;

a sounding reference signal uplink configuration dedicated aperiodic;

a hybrid automated repeat request (HARQ) process number;

a maximum number of scheduled subframes;

a multi-antenna port transmission mode; or

a flexible timing support indication between uplink grant and uplink transmission.

4. The method of claim 1 , wherein the cell configuration parameters further indicate at least one of:

a listen-before-talk (LBT) configuration parameter comprising at least one of:

a maximum energy detection threshold; or

an energy detection threshold offset;

an LBT procedure category comprising at least one of category 2, category 3, or category 4; or

a size of contention window for an LBT procedure.

5. The method of claim 1 , further comprising configuring, by the first base station, one or more mobility parameters towards a cell of the second base station based on the cell configuration parameters.

6. The method of claim 1 , further comprising transmitting, by the first base station to a second wireless device, measurement configuration parameters determined based on the cell configuration parameters.

7. The method of claim 1 , further comprising configuring, by the first base station, second cell configuration parameters of a second unlicensed cell of the first base station based on the cell configuration parameters.

8. The method of claim 1 , wherein the first base station receives the cell configuration parameters from the second base station via a core network entity.

9. The method of claim 1 , further comprising transmitting, by the second base station to a second wireless device, one or more parameters of the cell configuration parameters.

10. The method of claim 9 , further comprising transmitting, by the second base station via the unlicensed cell, transport blocks based on the cell configuration parameters.

11. A first base station comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the first base station to:

receive, from a second base station, cell configuration parameters of one or more cells of the second base station, the cell configuration parameters comprising:

at least one first information element (IE) indicating a first identifier of a first cell of the one or more cells;

at least one second IE indicating that the first cell is an unlicensed cell; and

at least one third IE indicating a radio frequency channel number of the unlicensed cell; and

at least one fourth IE indicating a bandwidth of the unlicensed cell; and

send, to the second base station, a request message for adding the second base station as a secondary base station for a wireless device after receiving the cell configuration parameters.

12. The first base station of claim 11 , wherein the cell configuration parameters further indicate at least one of:

a downlink frequency;

an uplink frequency;

a downlink bandwidth; or

an uplink bandwidth.

13. The first base station of claim 11 , wherein the cell configuration parameters further indicate at least one of:

an unlicensed cell subframe configuration;

a subframe start position;

a cross carrier scheduling configuration of an unlicensed uplink;

a physical downlink control channel (PDCCH) configuration;

a sounding reference signal uplink configuration dedicated aperiodic;

a hybrid automated repeat request (HARQ) process number;

a maximum number of scheduled subframes;

a multi-antenna port transmission mode; or

a flexible timing support indication between uplink grant and uplink transmission.

14. The first base station of claim 11 , wherein the cell configuration parameters further indicate at least one of:

a listen-before-talk (LBT) configuration parameter comprising at least one of:

a maximum energy detection threshold; or

an energy detection threshold offset;

an LBT procedure category comprising at least one of category 2, category 3, or category 4; or

a size of contention window for an LBT procedure.

15. The first base station of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the first base station to configure, by the first base station, one or more mobility parameters towards a cell of the second base station based on the cell configuration parameters.

16. The first base station of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the first base station to transmit, by the first base station to a second wireless device, measurement configuration parameters determined based on the cell configuration parameters.

17. The first base station of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the first base station to configure, by the first base station, second cell configuration parameters of a second unlicensed cell of the first base station based on the cell configuration parameters.

18. The first base station of claim 11 , wherein the first base station receives the cell configuration parameters from the second base station via a core network entity.

19. The first base station of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the first base station to transmit, by the second base station to a third wireless device, one or more parameters of the cell configuration parameters.

20. A system comprising:

a first base station comprising:

one or more first processors; and

first memory storing first instructions that, when executed by the one or more first processors, cause the first base station to send cell configuration parameters of one or more cells of the first base station, the cell configuration parameters comprising:

at least one first information element (IE) indicating a first identifier of a first cell of the one or more cells;

at least one second IE indicating that the first cell is an unlicensed cell; and

at least one third IE indicating a radio frequency channel number of the unlicensed cell; and

at least one fourth IE indicating a bandwidth of the unlicensed cell; and

a second base station comprising:

one or more second processors; and

second memory storing instructions that, when executed by the one or more second processors, cause the second base station to:

receive, from the first base station, the cell configuration parameters; and

send, to the first base station, a request message for adding the second base station as a secondary base station for a wireless device after receiving the cell configuration parameters.