Method and apparatus for cell switching

• US 9,526,057 B2
• Filed: 07/26/2013
• Issued: 12/20/2016
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yi, Yunjung, Kim, Byounghoon, Ahn, Joonkui, Seo, Dongyoun
• Primary Examiner(s): Liu, Jung-Jen
• Application Number:
  US14/415,981
• Publication Number:
  US 20150146692A1
• Time in Patent Office: 1,243 Days
• US Class Current: 1/1
• CPC Class Codes: H04W 36/0069 in case of dual connectivity, e.g. decoupled uplink/downlink
• CPC Class Codes: H04W 36/24 Reselection being triggered by specific parameters

Abstract

Disclosed are a method and an apparatus for transmitting data. A cell switching method can comprise the steps of: allowing a primary (P)-cell base station to enable a first secondary (S)-cell; allowing the P-cell base station to receive channel state information from a second S-cell; allowing the P-cell base station to determine the second S-cell as a switching S-cell on the basis of the channel state information; allowing the P-cell base station to disable the first S-cell and enable the second S-cell.

Claims

1. A method for performing a cell switching in a wireless communication system, the method comprising:

activating, by a base station of a primary (P)-cell, a first secondary (S)-cell;

receiving, by the base station of the P-cell, channel state information from a second S-cell;

determining, by the base station of the P-cell, the second S-cell as a switching S-cell based on the channel state information; and

deactivating, the base station of the P-cell, the first S-cell;

activating, by the base station of the P-cell, the second S-cell; and

configuring, by the base station of the P-cell, a transmission of a switching random access preamble as uplink data transmitted to the first S-cell by a wireless device,

wherein the switching random access preamble is configured to be transmitted by the wireless device in order to perform the cell switching of the base station of the P-cell,

wherein the wireless device determines whether to perform the cell switching based on the switching random access preamble,

wherein the first S-cell and the second S-cell are included in an S-cell group,

wherein the S-cell group is a set of a plurality of S-cells for which an identical physical cell identifier is configured and operated based on an identical center frequency,

wherein the channel state information includes information of a channel which is obtained by overhearing the uplink data that the wireless device transmits to the first S-cell by the second S-cell,

wherein the P-cell, the first S-cell and the second S-cell are aggregated by a carrier aggregation, and

wherein the first S-cell and the second S-cell are activated by the P-cell.

2. The method of claim 1, wherein the first S-cell transmits information for demodulating the uplink data of the second S-cell to the second S-cell, and

wherein the information for demodulating the uplink data includes an uplink channel or transmission period information of a signal, offset information and sequence information.

3. The method of claim 1, further comprising:

transmitting, by the base station of the P-cell, information on a system frequency or a cell configuration for a group index identifier of the second S-cell to the wireless device when the system frequency of the second S-cell or the cell configuration information of the second S-cell is different from the first S-cell,

wherein activating the second S-cell further comprises transmitting the group index identifier of the second S-cell to the wireless device by the base station of the P-cell, if the system frequency of the second S-cell or the cell configuration information is different from the first S-cell, and

wherein the group index identifier is information for distinguishing an S-cell included in the S-cell group by the wireless device.

4. The method of claim 3, wherein the cell configuration information includes information on a carrier type, information on a transmission period of a primary synchronization signal (PSS) or a secondary synchronization signal (SSS) transmitted to the second S-cell, and transmission offset information.

5. A base station of a primary (P)-cell that performs cell switching in a wireless communication system, the base station comprising:

a processor; and

a radio frequency (RF) unit,

wherein the processor is configured to;

activate a first secondary (S)-cell,

receive channel state information from a second S-cell,

determine the second S-cell as a switching S-cell based on the channel state information,

deactivate the first S-cell and activate the second S-cell, and

configure a transmission of a switching random access preamble as uplink data transmitted to the first S-cell by a wireless device,

wherein the switching random access preamble is configured to be transmitted by the wireless device in order to perform the cell switching of the base station of the P-cell,

wherein the wireless device determines whether to perform the cell switching based on the switching random access preamble,

wherein the first S-cell and the second S-cell are included in an S-cell group,

wherein the S-cell group is a set of a plurality of S-cells for which an identical physical cell identifier is configured and operated based on an identical center frequency,

wherein the channel state information includes information of a channel which is obtained by overhearing the uplink data that the wireless device transmits to the first S-cell by the second S-cell,

wherein the P-cell, the first S-cell and the second S-cell are aggregated by a carrier aggregation, and

wherein the first S-cell and the second S-cell are cells activated by the P-cell.

6. The base station of claim 5, wherein the first S-cell transmits information for demodulating the uplink data of the second S-cell to the second S-cell, and

wherein the information for demodulating the uplink data includes an uplink channel or transmission period information of a signal, offset information and sequence information.

7. The base station of claim 5, wherein the processor is further configured to:

transmit information on a system frequency or a cell configuration for a group index identifier of the second S-cell to the wireless device when the system frequency of the second S-cell or the cell configuration information of the second S-cell is different from the first S-cell, and

transmit the group index identifier of the second S-cell for activating the second S-cell to the wireless device, if the system frequency of the second S-cell or the cell configuration information is different from the first S-cell, and

wherein the group index identifier is information for distinguishing an S-cell included in the S-cell group by the wireless device.

8. The base station of claim 7, wherein the cell configuration information includes information on a carrier type, information on a transmission period of a primary synchronization signal (PSS) or a secondary synchronization signal (SSS) transmitted to the second S-cell, and transmission offset information.