# US 2014/0194126 A1 · Mobile station, base station, and method for managing synchronization state

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- Number: US 2014/0194126 A1
- Document ID: US20140194126A1
- Status: Published application
- Kind: A1
- Application number: 14/238,385
- Filed: 2012-08-07
- Published: 2014-07-10
- Earliest claimed: 2011-08-12
- Assignees: Sharp Kabushiki Kaisha
- Inventors: Hidekazu Tsuboi; Katsunari Uemura; Yasuyuki Kato
- Web page: https://patentgrep.com/patent/US20140194126A1

## CPC

- H04W 36/0072: {of resource information of target access point}
- H04W 56/0045: {compensating for timing error by altering transmission time}
- H04W 74/0833: Random access procedures, e.g. with 4-step access
- H04W 74/0838: using contention-free random access [CFRA]
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A synchronization state is efficiently managed in a mobile station to which cells are allocated. A base station notifies the mobile station of information about whether or not a transmission timing before a handover for each of cell groups of the mobile station is to be applied after the handover. The mobile station sets whether or not the transmission timing adjusted for each cell group is to be applied after the handover, on the basis of the received information.

## Claims

### Claim at position 1

1-13. (canceled)

### Claim 14

A mobile station that communicates with a base station by aggregating a plurality of cells having different frequency bands,
wherein the plurality of cells having different frequency bands are grouped into any one of cell groups, each of which includes cells having an identical transmission timing, and
wherein the mobile station
adjusts the transmission timing of each of the cell groups which are set from the base station, and
sets whether or not the transmission timing adjusted for each of the cell groups is to be applied after a handover, on the basis of information which describes for each of the cell groups whether or not the transmission timing before the handover is to be applied after the handover and which is transmitted from the base station.

### Claim 15 (depends on 14)

The mobile station according to claim 14,
wherein the information is information for specifying whether or not a random access procedure is required to be performed after the handover, for each of the cell groups or each of cells of the cell group, and
wherein a transmission timing of a cell group for which the random access procedure is not required in the information or a cell group including a cell for which the random access procedure is not required in the information is applied after the handover.

### Claim 16 (depends on 14)

The mobile station according to claim 14,
wherein a state of the cell to which the transmission timing is applied after the handover is to be continued after the handover.

### Claim 17

A base station that communicates with a mobile station by aggregating a plurality of cells having different frequency bands,
wherein the plurality of cells having different frequency bands are grouped into any one of cell groups, each of which includes cells having an identical transmission timing, and
wherein the base station transmits information describing whether or not a transmission timing before a handover for each of the cell groups of the mobile station is to be applied after the handover.

### Claim 18

A method for managing a synchronization state of a mobile station that communicates with a base station by aggregating a plurality of cells having different frequency bands,
wherein the plurality of cells having different frequency bands are grouped into any one of cell groups, each of which includes cells having an identical transmission timing,
the method comprising:
adjusting, by using the mobile station, the transmission timing of each of the cell groups which are set from the base station;
receiving, by using the mobile station, information describing whether or not a transmission timing before a handover for each of the cell groups is to be applied after the handover, from the base station, and storing the information; and
applying, by using the mobile station, the transmission timing before the handover to the transmission timing after the handover, for the cell groups to which the transmission timing before the handover is to be applied after the handover.

### Claim 19 (depends on 18)

The method for managing a synchronization state of a mobile station according to claim 18,
wherein the information is information for specifying whether or not a random access procedure is required to be performed after the handover, for each of the cell groups or each of cells of the cell group, and
wherein a transmission timing of a cell group for which the random access procedure is not required in the information or a cell group including a cell for which the random access procedure is not required in the information is applied after the handover.

### Claim 20 (depends on 18)

The method for managing a synchronization state of a mobile station according to claim 18,
wherein a state of the cell to which the transmission timing is applied after the handover is to be continued after the handover.