METHOD AND APPARATUS FOR CELL SWITCHING

• US 20150146692A1
• Filed: 07/26/2013
• Published: 05/28/2015
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Byounghoon, Seo, Dongyoun, Yi, Yunjung, Ahn, Joonkui
• Granted Patent: US 9,526,057 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• 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 cell switching, 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 first S-cell and activating the second S-cell by the base station of the P-cell,

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 uplink data that a 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,

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. The method of claim 1 further comprising:

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

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

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

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

wherein the RF unit configured to receive the channel state information from the second S-cell,

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 uplink data that a 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.

7. The base station of claim 6,

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.

8. The base station of claim 6,

wherein the process 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,

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

9. The base station of claim 8,

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.

10. The base station of claim 6,

wherein the process is further configured to:

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

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