Method for performing handover, user equipment, and radio communication system

Patent metadata

Field	Value
Publication number	US-9781644-B2
Application number	US-201715436378-A
Country	US
Kind code	B2
Filing date	Feb 17, 2017
Priority date	Dec 16, 2009
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A mobile station in a wireless communication network. The mobile station includes a radio communication that transmits an access request message to a base station via a first communication resource, and receives a timing adjustment in response to the access request message from the base station. The mobile station also includes an adjustment value storage unit that stores the timing adjustment, and a control unit that adjusts access timing corresponding to a second communication resource based on the timing adjustment value stored in the adjustment value storage unit. The radio communication unit then communicates with the base station via the first communication resource and the second communication resource.

First claim

The invention claimed is:

1. A mobile station in a wireless communication network, comprising:
a radio communication interface configured to communicate with a base station via a communication channel formed by aggregating a plurality of component carriers;
processing circuitry configured to control a handover from a first base station to a second base station by the radio communication interface, and to skip a random access, to the second base station, on at least one of two or more component carriers; and
an adjustment value memory configured to store a timing adjustment value notified for a component carrier of the two or more component carriers on which random access is carried out;
wherein the processing circuitry is configured to adjust transmission timing on a component carrier on which a random access has been skipped by using the timing adjustment value stored in the memory.

2. The mobile station of claim 1 , wherein
the processing circuitry is configured to acquire synchronization with the base station via the component carrier for which random access is carried out, and
the radio communication interface is configured to transmit an access request message based on the synchronization.

3. The mobile station of claim 1 , wherein
the timing adjustment value is based on a signal propagation characteristic between the mobile station and the base station.

4. The mobile station of claim 1 , wherein
the timing adjustment value depends on a frequency of the component carrier for which random access is carried out.

5. The mobile station of claim 1 , wherein
the two or more component carriers are in closest proximity to each other relative to other available component carriers.

6. The mobile station of claim 1 , wherein
the two or more component carriers are adjacent to each other.

7. The mobile station of claim 1 , wherein
the two or more component carriers are within a predetermined threshold of each other.

8. A base station in a wireless communication network, the base station comprising:
a radio communication interface configured to communicate with a mobile station via a communication channel formed by aggregating a plurality of component carriers;
processing circuitry configured to control a handover of the mobile station from another base station,
wherein, the processing circuitry is configured to allocate two or more component carrier, and notify timing adjustment value to the mobile station for a component carrier of the two or more component carriers on which the mobile station carries out random access, and
wherein the radio communication interface is configured to receive information, about a component carrier of the two or more component carriers for which random access is skipped, transmitted from the mobile station on a transmission timing adjusted by the mobile station using the timing adjustment value notified for the component carrier on which the mobile station carries out random access.

9. The base station of claim 8 , wherein
the processing circuitry is configured to assign the two or more component carriers to be adjacent to each other.

10. The base station of claim 8 , wherein
the processing circuitry is configured to assign the two or more component carriers be within a predetermined threshold to each other.

11. The base station of claim 8 , wherein
the processing circuitry is configured to assign a second component carrier of the two or more component carriers, which is one of a plurality of available component carriers closest in proximity to a first component carrier of the two or more component carriers.

12. A wireless communication system comprising:
a mobile station;
a first base station; and
a second base station,
wherein the mobile station includes:
a first radio communication interface configured to communicate with the second base station via a communication channel formed by aggregating a plurality of component carriers; and
a first control unit configured to control a handover from the first base station to the second base station by the first radio communication interface, and to skip a random access, to the second base station, on at least one of two or more component carriers; and
an adjustment value memory configured to store a timing adjustment value notified for a component carrier of the two or more component carriers on which random access is carried out;
wherein the first control unit is configured to adjust transmission timing on a component carrier on which a random access has been skipped by using the timing adjustment value stored in the adjustment value memory, and

the second base station includes:
a second radio communication interface configured to communicate with a mobile station via a communication channel formed by aggregating a plurality of component carriers;
a second control unit configured to control a handover of the mobile station from the first base station,

wherein, the second control unit is configured to allocate two or more component carrier, and notify timing adjustment value to the mobile station for a component carrier of the two or more component carriers on which the mobile station carries out random access, and
wherein the second radio communication interface is configured to receive information, about a component carrier of the two or more component carriers for which random access is skipped, transmitted from the mobile station on a transmission timing adjusted by the mobile station using the timing adjustment value notified for the component carrier on which the mobile station carries out random access.

13. A method executed by a mobile station in a wireless communication network comprising:
communicating with a base station via a communication channel formed by aggregating a plurality of component carriers;
controlling a handover from a first base station to a second base station;
skipping a random access, to the second base station, on at least one of two or more component carriers;
storing a timing adjustment value notified for a component carrier of the two or more component carriers on which random access is carried out; and
adjusting transmission timing on a component carrier on which a random access has been skipped by using the stored timing adjustment value.

14. A method executed by a base station in a wireless communication network comprising:
communicating with a mobile station via a communication channel formed by aggregating a plurality of component carriers;
controlling a handover of the mobile station from another base station;
allocating two or more component carrier, and notify timing adjustment value to the mobile station for a component carrier of the two or more component carriers on which the mobile station carries out random access; and
receiving information, about a component carrier of the two or more component carriers for which random access is skipped, transmitted from the mobile station on a transmission timing adjusted by the mobile station using the timing adjustment value notified for the component carrier on which the mobile station carries out random access.

Assignees

• Sony Corp

Inventors

• Takano Hiroaki
• Morioka Yuichi
• Sawai Ryo

Classifications

• H04W74/0833 Primary

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

• H04W72/0453

  Resources in frequency domain, e.g. a carrier in FDMA · CPC title

• H04W56/001 Primary

  Synchronization between nodes · CPC title

• H04W36/0016

  Hand-off preparation specially adapted for end-to-end data sessions · CPC title

• H04W36/00

  Hand-off or reselection arrangements · CPC title