Handover random access

1. A method comprising:

transmitting, by a wireless device and to a base station associated with a first cell, a first message comprising a measurement report;

receiving, by the wireless device and from the base station, a second message comprising a command for a handover to a second cell, wherein the second message comprises one or more parameters associated with a type of a random access procedure for the handover; and

transmitting, by the wireless device and for the handover to the second cell, a random access preamble employing the type of the random access procedure.

2. The method of claim 1 , further comprising transmitting, by the wireless device, one or more transport blocks overlapping in time with the random access preamble.

3. The method of claim 2 , wherein the one or more transport blocks comprise one or more of:

a handover complete message;

uplink data;

a buffer status report; or

an identifier of the wireless device.

4. The method of claim 1 , wherein the one or more parameters of the second message comprise, for the random access procedure, one or more of:

a preamble identifier; or

random access resource information.

5. The method of claim 1 , wherein the second message further comprises:

the computing device comprises a core network device; and

the second message comprises an indication that the handover is requested.

6. The method of claim 1 , wherein the second cell is a cell of one or more second cells, wherein the measurement report is based on the one or more second cells, and wherein the method further comprises:

receiving, from the one or more second cells, a plurality of third messages comprising one or more of:

an indication of a power associated with a cell;

an indication of a quality associated with a cell; or

an indication of a cell priority.

7. The method of claim 1 , wherein the one or more parameters of the second message indicate the type of the random access procedure.

8. The method of claim 1 , wherein the second message comprises a preamble identifier, and wherein the method further comprises:

determining, based on the preamble identifier, radio resources associated with the random access procedure.

9. The method of claim 1 , wherein the second message comprises:

random access channel configuration information for a two-step random access procedure; and

radio resource configuration parameters for the two-step random access procedure.

10. The method of claim 1 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

11. A method comprising:

receiving, by a base station associated with a first cell and from a wireless device, a first message comprising a measurement report;

transmitting, to a computing device, a second message comprising an indication of a handover to a second cell;

receiving, from the computing device, a third message associated with a type of a random access procedure for the handover; and

transmitting, to the wireless device, a fourth message that comprises one or more parameters associated with the type of the random access procedure.

12. The method of claim 11 , wherein:

the computing device comprises a second base station associated with the second cell; and

the second message comprises a handover request.

13. The method of claim 11 , wherein:

the computing device comprises a core network device; and

the second message indicates that the handover is requested.

14. The method of claim 11 , wherein the second message indicates that the handover is requested, and wherein the method further comprises:

transmitting, by the computing device, to a second base station, and based on the second message, a fifth message comprising a handover request; and

receiving, by the computing device and from the second base station, a sixth message indicating the type of the random access procedure for the handover and comprising an acknowledgement of the handover request.

15. The method of claim 11 , wherein the one or more parameters of the fourth message comprise, for the random access procedure, one or more of:

a preamble identifier; or

random access resource information.

16. The method of claim 11 , wherein the fourth message further comprises timing advance information for transmission, by the wireless device, of one or more of: a random access preamble or one or more transport blocks.

17. The method of claim 16 , wherein the timing advance information comprises one or more of:

an indication of a zero timing advance; or

a value for a timing advance, wherein the value is estimated by the base station or the computing device.

18. The method of claim 11 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

19. The method of claim 11 , wherein the one or more parameters of the fourth message indicate the type of the random access procedure.

20. A method comprising:

receiving, by a computing device and from a base station associated with a first cell, a first message comprising an indication for a handover of a wireless device to a second cell; and

transmitting, to the base station, a second message associated with a type of a random access procedure for the handover of the wireless device.

21. The method of claim 20 , wherein:

the computing device comprises a second base station that is associated with the second cell; and

the second message comprises a handover request.

22. The method of claim 20 , wherein:

timing advance information for transmission of one or more of: the random access preamble or one or more transport blocks.

23. The method of claim 20 , further comprising:

transmitting, by the computing device, to a second base station, and based on the first message, a third message comprising a handover request; and

receiving, by the computing device and from the second base station, a fourth message indicating the type of the random access procedure for the handover and comprising an acknowledgement of the handover request.

24. The method of claim 20 , further comprising:

receiving, from a second base station associated with the second cell, a handover acknowledgment indicating proceeding with the handover.

25. The method of claim 20 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

26. The method of claim 20 , wherein the handover is a handover of the wireless device from the first cell to the second cell.

27. The method of claim 20 , wherein the second message indicates the type of the random access procedure.

28. A wireless device comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the wireless device to perform:

transmitting, to a base station associated with a first cell, a first message comprising a measurement report;

receiving, from the base station, a second message comprising a command for a handover to a second cell, wherein the second message comprises one or more parameters associated with a type of a random access procedure for the handover; and

transmitting, for the handover to the second cell, a random access preamble employing the type of the random access procedure.

29. The wireless device of claim 28 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to perform:

transmitting one or more transport blocks overlapping in time with the random access preamble.

30. The wireless device of claim 28 , wherein the one or more parameters of the second message indicate the type of the random access procedure.

31. The wireless device of claim 28 , wherein the second message comprises a preamble identifier, and wherein the instructions, when executed by the one or more processors, further cause the wireless device to perform:

determining, based on the preamble identifier, radio resources associated with the random access procedure.

32. The wireless device of claim 28 , wherein the second message comprises:

random access channel configuration information for a two-step random access procedure; and

radio resource configuration parameters for the two-step random access procedure.

33. The wireless device of claim 28 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

34. A base station comprising:

one or more processors; and

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

receiving, from a wireless device, a first message comprising a measurement report, wherein the base station is associated with a first cell;

transmitting, to a computing device, a second message comprising an indication of a handover to a second cell;

receiving, from the computing device, a third message associated with a type of a random access procedure for the handover; and

transmitting, to the wireless device, a fourth message that comprises one or more parameters associated with the type of the random access procedure.

35. The base station of claim 34 , wherein:

the computing device comprises a second base station associated with the second cell, and the second message comprises a handover request; or

the computing device comprises a core network device, and the second message indicates that the handover is requested.

36. The base station of claim 34 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

37. The base station of claim 34 , wherein the one or more parameters of the fourth message indicate the type of the random access procedure.

38. A computing device comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the computing device to perform:

receiving, from a base station associated with a first cell, a first message comprising an indication for a handover of a wireless device to a second cell; and

transmitting, to the base station, a second message associated with a type of a random access procedure for the handover of the wireless device.

39. The computing device of claim 38 , wherein:

the computing device comprises a second base station that is associated with the second cell, and the second message comprises a handover request; or

the computing device comprises a core network device, and the second message comprises an indication that the handover is requested.

40. The computing device of claim 38 , wherein the instructions, when executed by the one or more processors, further cause the computing device to perform:

transmitting, to a second base station, and based on the first message, a third message comprising a handover request; and

receiving, from the second base station, a fourth message indicating the type of the random access procedure for the handover and comprising an acknowledgement of the handover request.

41. The computing device of claim 38 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

42. The computing device of claim 38 , wherein the second message indicates the type of the random access procedure.

43. A non-transitory computer-readable medium storing instructions that, when executed, configure a wireless device to perform:

transmitting, to a base station associated with a first cell, a first message comprising a measurement report;

receiving, by the wireless device and from the base station, a second message comprising a command for a handover to a second cell, wherein the second message comprises one or more parameters associated with a type of a random access procedure for the handover; and

transmitting, by the wireless device and for the handover to the second cell, a random access preamble employing the type of the random access procedure.

44. The non-transitory computer-readable medium of claim 43 , wherein the instructions, when executed, further configure the wireless device to perform:

transmitting one or more transport blocks overlapping in time with the random access preamble.

45. The non-transitory computer-readable medium of claim 43 , wherein the one or more parameters of the second message indicate the type of the random access procedure.

46. The non-transitory computer-readable medium of claim 43 , wherein the second message comprises a preamble identifier, and wherein the instructions, when executed, further configure the wireless device to perform:

determining, based on the preamble identifier, radio resources associated with the random access procedure.

47. The non-transitory computer-readable medium of claim 43 , wherein the second message comprises:

random access channel configuration information for a two-step random access procedure; and

radio resource configuration parameters for the two-step random access procedure.

48. The non-transitory computer-readable medium of claim 43 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

49. A non-transitory computer-readable medium storing instructions that, when executed, configure a base station to perform:

receiving, from a wireless device, a first message comprising a measurement report, wherein the base station is associated with a first cell;

transmitting, to a computing device, a second message comprising an indication of a handover to a second cell;

receiving, from the computing device, a third message associated with a type of a random access procedure for the handover; and

transmitting, to the wireless device, a fourth message that comprises one or more parameters associated with the type of the random access procedure.

50. The non-transitory computer-readable medium of claim 49 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

51. The non-transitory computer-readable medium of claim 49 , wherein the one or more parameters of the fourth message indicate the type of the random access procedure.

52. A non-transitory computer-readable medium storing instructions that, when executed, configure a computing device to perform:

receiving, from a base station associated with a first cell, a first message comprising an indication for a handover of a wireless device to a second cell; and

transmitting, to the base station, a second message associated with a type of a random access procedure for the handover of the wireless device.

53. The non-transitory computer-readable medium of claim 52 , wherein the instructions, when executed, further configure the computing device to perform:

transmitting, to a second base station, and based on the first message, a third message comprising a handover request; and

receiving, from the second base station, a fourth message indicating the type of the random access procedure for the handover and comprising an acknowledgement of the handover request.

54. The non-transitory computer-readable medium of claim 52 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

55. The non-transitory computer-readable medium of claim 52 , wherein the second message indicates the type of the random access procedure.

56. A system comprising:

a wireless device comprising:

one or more processors; and

memory storing instructions; and

a base station associated with a first cell, the base station comprising:

one or more processors; and

memory storing instructions,

wherein the instructions stored in the memory of the wireless device, when executed by the one or more processors of the wireless device, cause the wireless device to perform:

transmitting, to the base station, a first message comprising a measurement report;

receiving, from the base station, a second message comprising a command for a handover to a second cell, wherein the second message comprises one or more parameters associated with a type of a random access procedure for the handover; and

transmitting, for the handover to the second cell, a random access preamble employing the type of the random access procedure, and

wherein the instructions stored in the memory of the base station, when executed by the one or more processors of the base station, cause the base station to perform:

receiving the first message;

transmitting, to a computing device, a third message comprising an indication of the handover to the second cell;

receiving, from the computing device, a fourth message associated with the type of the random access procedure for the handover; and

transmitting, to the wireless device, the second message.

57. The system of claim 56 , wherein the instructions stored in the memory of the wireless device, when executed by the one or more processors of the wireless device, further cause the wireless device to perform:

transmitting one or more transport blocks overlapping in time with the random access preamble.

58. The system of claim 56 , wherein the one or more parameters of the second message indicate the type of the random access procedure.

59. The system of claim 56 , wherein the second message comprises a preamble identifier, and wherein the instructions stored in the memory of the wireless device, when executed by the one or more processors of the wireless device, further cause the wireless device to perform:

determining, based on the preamble identifier, radio resources associated with the random access procedure.

60. The system of claim 56 , wherein the second message comprises:

random access channel configuration information for a two-step random access procedure; and

radio resource configuration parameters for the two-step random access procedure.

61. The system of claim 56 , wherein the type of the random access procedure for the handover is one of a two-step random access procedure or a four-step random access procedure.

62. The system of claim 56 , further comprising the computing device, wherein the computing device comprises:

one or more processors; and

memory storing instructions that, when executed by the one or more processors of the computing device, cause the computing device to perform:

receiving the third message; and

transmitting, to the base station, the fourth message.