Radio access for a wireless device and base station

1. A method comprising:

a) receiving, by a wireless device, at least one control message from a base station, said at least one control message causing in said wireless device:

i) configuration of a plurality of cells comprising a primary cell and at least one secondary cell;

ii) assignment of each of said at least one secondary cell to a cell group in a plurality of cell groups, said plurality of cell groups comprising:

(1) a primary cell group comprising a first subset of said plurality of cells, said first subset comprising said primary cell; and

(2) a secondary cell group comprising a second subset of said at least one secondary cell; and

iii) configuration of a time alignment timer for each of said plurality of cell groups, said time alignment timer starting or restarting in response to said wireless device receiving a timing advance command to adjust uplink transmission timing of a commanded cell group in said plurality of cell groups, said commanded cell group considered:

(1) out-of-sync in response to said time alignment timer being expired or not running; and

(2) in-sync in response to said time alignment timer running;

b) initiating, by said wireless device while said primary cell group is in-sync, a random access process for a secondary cell in said secondary cell group in response to receiving a control command;

c) transmitting, by said wireless device, a first random access preamble on random access resources of said secondary cell; and

d) aborting, by said wireless device, said random access process on said secondary cell if said primary cell group becomes out-of-sync.

2. The method of claim 1 , further comprising transmitting, autonomously by said wireless device, a second random access preamble on said primary cell group to obtain uplink transmission timing of said primary cell group if said primary cell group becomes out-of-sync.

3. The method of claim 2 , further comprising receiving a random access response on said primary cell from said base station.

4. The method of claim 1 , further comprising releasing said at least one secondary cell if said primary cell group becomes out-of-sync.

5. The method of claim 1 , further comprising ignoring, by said wireless device, any message received in downlink control channels of each of said at least one secondary cell if said primary cell group becomes out-of-sync.

6. The method of claim 1 , further comprising stopping, by said wireless device, monitoring downlink control channels of each of said at least one secondary cell if said primary cell group becomes out-of-sync.

7. The method of claim 1 , further comprising ignoring, by said wireless device, any timing advance command for said secondary cell group if said primary cell group becomes out-of-sync.

8. The method of claim 1 , wherein:

a) said primary cell group comprises a first subset of said plurality of cells, said first subset comprising said primary cell, uplink transmissions by said wireless device in said primary cell group employing a first synchronization signal transmitted on said primary cell as a primary timing reference; and

b) said secondary cell group comprises a second subset of said at least one secondary cell, said second subset comprising a reference secondary cell, uplink transmissions in said secondary cell group employing a second synchronization signal on said reference secondary cell as a secondary timing reference.

9. The method of claim 1 , wherein said control command comprises:

a) a mask index; and

b) a preamble identifier of a random access preamble.

10. The method of claim 1 , wherein said control command further comprises an index identifying said secondary cell if said control command is not transmitted on said secondary cell.

11. A method comprising:

a) receiving, by a wireless device, at least one control message from a base station, said at least one control message causing in said wireless device:

i) configuration of a plurality of cells comprising a primary cell and at least one secondary cell;

ii) assignment of each of said at least one secondary cell to a cell group in a plurality of cell groups, said plurality of cell groups comprising:

(1) a primary cell group comprising a first subset of said plurality of cells, said first subset comprising said primary cell; and

(2) a secondary cell group comprising a second subset of said at least one secondary cell; and

iii) configuration of a time alignment timer for each of said plurality of cell groups, said time alignment timer starting or restarting in response to said wireless device receiving a timing advance command to adjust uplink transmission timing of a commanded cell group in said plurality of cell groups;

b) receiving, by said wireless device while a first time alignment timer of said primary cell group is running, a control command initiating a random access process for a secondary cell in said secondary cell group in said wireless device; and

c) aborting, by said wireless device, said random access process on said secondary cell if said first time alignment timer of said primary cell group expires.

12. The method of claim 11 , wherein said aborting, by said wireless device, of said random access process causes said wireless device:

a) to stop transmission of a random access preamble for said random access process, if said random access preamble has not yet been transmitted; and

b) to stop monitoring for random access responses corresponding to said random access preamble, if said random access preamble has been transmitted.

13. The method of claim 11 , further comprising transmitting, autonomously by said wireless device, a second random access preamble on said primary cell group to obtain uplink transmission timing of said primary cell group if said first time alignment timer of said primary cell group expires.

14. The method of claim 11 , further comprising said wireless device configuring said random access resources in response receiving said at least one control message.

15. The method of claim 11 , wherein said at least one control message comprises a plurality of random access resource parameters for said secondary cell, said plurality of random access resource parameters comprising an index, a frequency offset, and a plurality of sequence parameters.

16. A wireless device comprising:

a) one or more communication interfaces;

b) one or more processors; and

c) memory storing instructions that, when executed, cause said wireless device to:

i) receive at least one control message from a base station, said at least one control message causing in said wireless device:

(1) configuration of a plurality of cells comprising a primary cell and at least one secondary cell;

(2) assignment of each of said at least one secondary cell to a cell group in a plurality of cell groups, said plurality of cell groups comprising:

(a) a primary cell group comprising a first subset of said plurality of cells, said first subset comprising said primary cell; and

(b) a secondary cell group comprising a second subset of said at least one secondary cell; and

(3) configuration of a time alignment timer for each of said plurality of cell groups, said time alignment timer starting or restarting in response to said wireless device receiving a timing advance command to adjust uplink transmission timing of a commanded cell group in said plurality of cell groups;

ii) receive, while a first time alignment timer of said primary cell group is running, a control command initiating a random access process for a secondary cell in said secondary cell group in said wireless device; and

iii) abort said random access process on said secondary cell if said first time alignment timer of said primary cell group expires.

17. The wireless device of claim 16 , wherein said control command further comprises an index identifying said secondary cell if said control command is not transmitted on said secondary cell.

18. The wireless device of claim 16 , wherein said control command comprises:

a) a mask index; and

b) a preamble identifier of a random access preamble.

19. The wireless device of claim 16 , wherein:

a) said primary cell group comprises a first subset of said plurality of cells, said first subset comprising said primary cell, uplink transmissions by said wireless device in said primary cell group employing a first synchronization signal transmitted on said primary cell as a primary timing reference; and

b) said secondary cell group comprises a second subset of said at least one secondary cell, said second subset comprising a reference secondary cell, uplink transmissions in said secondary cell group employing a second synchronization signal on said reference secondary cell as a secondary timing reference.

20. The wireless device of claim 16 , wherein said instructions further cause said wireless device to release said at least one secondary cell if said first time alignment timer of said primary cell group expires.