Handover random access

Patent metadata

Field	Value
Publication number	US-10568007-B2
Application number	US-201815933301-A
Country	US
Kind code	B2
Filing date	Mar 22, 2018
Priority date	Mar 22, 2017
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

Systems, apparatuses, and methods are described for wireless communications. Random access procedures may include various types of procedures, such as 4-step or 2-step random access procedures. One or more indicators may be included in one or more messages for a handover to indicate a type of a random access procedure.

First claim

The invention claimed is:

1. A method comprising:
transmitting, by a wireless device and to a first base station associated with a first cell, a first message comprising a measurement report based on one or more second cells;
receiving, by the wireless device and from the first base station, a second message comprising a command for a handover from the first cell to a second cell of the one or more second cells, wherein the second message comprises one or more parameters indicating a type of a random access procedure for the handover, and wherein the type of the random access procedure comprises a two-step random access procedure or a four-step random access procedure; and
transmitting, by the wireless device and to a second base station associated with the second cell, a random access preamble employing the type of the random access procedure indicated in the second message.

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

6. The method of claim 5 , further comprising:
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 , further comprising transmitting, by the wireless device and in a first step of a four-step random access procedure, a second random access preamble.

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. A method comprising:
receiving, by a first base station associated with a first cell and from a wireless device, a first message comprising a measurement report based on one or more second cells;
determining, based on the measurement report, to handover the wireless device from the first cell to a second cell of the one or more second cells;
transmitting, by the first base station and to a third device, a second message comprising an indication for the handover;
receiving, by the first base station and from the third device, a third message indicating a type of a random access procedure for the handover, wherein the type of the random access procedure comprises a two-step random access procedure or a four-step random access procedure; and
transmitting, by the first base station and to the wireless device, a fourth message comprising:
one or more parameters indicating the type of the random access procedure for the handover; and
a command to proceed with the handover.

11. The method of claim 10 , wherein:
the third device comprises a second base station associated with the second cell; and
the second message comprises a handover request.

12. The method of claim 10 , wherein:
the third device comprises a core network device; and
the second message indicates that the handover is requested.

13. The method of claim 12 , further comprising:
transmitting, by the core network device, to a second base station, and based on the second message, a fifth message comprising a handover request; and
receiving, by the core network 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.

14. The method of claim 10 , 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.

15. The method of claim 10 , 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.

16. The method of claim 15 , 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 first base station or the third device.

17. A method comprising:
receiving, by a network device and from a first base station associated with a first cell, a first message comprising an indication for a handover of a wireless device from the first cell to a second cell of one or more second cells;
determining, by the network device and based on the first message, to proceed with the handover; and
transmitting, by the network device and to the first base station, a second message comprising:
an acknowledgement for the handover; and
one or more parameters indicating a type of a random access procedure for the handover, wherein the type of the random access procedure comprises a two-step random access procedure or a four-step random access procedure.

18. The method of claim 17 , wherein:
the network device comprises a second base station that is associated with the second cell; and
the second message comprises a handover request.

19. The method of claim 17 , wherein:
the network device comprises a core network device; and
the second message comprises an indication that the handover is required.

20. The method of claim 19 , further comprising:
transmitting, by the core network device, to a second base station, and based on the first message, a third message comprising a handover request; and
receiving, by the core network 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 a request for a handover request.

Assignees

• Comcast Cable Comm Llc

Inventors

• Park Kyungmin
• Dinan Esmael Hejazi
• Jeon Hyoungsuk

Classifications

• H04W36/0077 Primary

  of access information of target access point · CPC title

• H04W74/0833

  Random access procedures, e.g. with 4-step access · CPC title

• H04W36/30

  by measured or perceived connection quality data · CPC title

• H04W36/08

  Reselecting an access point · CPC title

• H04W74/0836

  with 2-step access · CPC title