Method for a user terminal to random access a carrier aggregation mobile communication system

• US 8,861,460 B2
• Filed: 06/07/2010
• Issued: 10/14/2014
• Est. Priority Date: 06/07/2009
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Chun, Sung Duck, Jung, Sung Hoon, Yi, Seung June, Lee, Young Dae, Park, Sung Jun
• Primary Examiner(s): Ly, Anh-Vu
• Assistant Examiner(s): LOPEZ-VARGAS, GUSTAVO E
• Application Number:
  US13/376,588
• Publication Number:
  US 20120076104A1
• Time in Patent Office: 1,590 Days
• Field of Search: 370/328, 370/329, 370/330, 370/252, 370/280, 455/73, 455/450
• US Class Current: 370/329
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

A method for random access to a base station by a user equipment (UE) in a mobile communication system using carrier aggregation in which communication is conducted over a plurality of component carriers, and a terminal for the method are disclosed. When the UE performs a contention-based random access procedure in the mobile communication system to which CA technology is applied, the UE considers an uplink grant signal as a contention resolution message when receiving the uplink grant signal from a eNB only when the uplink grant signal is received through a downlink CC corresponding to an uplink CC used to transmit a random access preamble or a third message, to thereby prevent contention resolution from being erroneously ended.

Claims

1. A method for performing a random access procedure in a mobile communication system supporting carrier aggregation using a primary carrier and one or more secondary carriers, the method performed by a User Equipment (UE) and comprising:

transmitting a first message comprising a random access preamble to an evolved NodeB (eNB) through the primary carrier;

receiving a second message including first uplink (UL) grant information as a response to the random access preamble through the primary carrier;

transmitting a third message including identity information of the UE to the eNB through an uplink radio resource corresponding to the first UL grant information; and

receiving a Physical Downlink Control Channel (PDCCH) indicated by the identity information of the UE from the eNB,

wherein, when the PDCCH is received through the primary carrier, the UE considers a contention resolution procedure according to transmission of the third message as a successful procedure, and

wherein, when the PDCCH is received through the one or more secondary carriers, the UE considers the contention resolution procedure as an unsuccessful procedure.

2. The method according to claim 1,

wherein the UE includes a physical layer module and a Medium Access Control (MAC) layer module, and

wherein the MAC layer module determines that the contention resolution procedure is successful only when the physical layer module reports reception of the PDCCH through the primary carrier to the MAC layer module.

3. The method according to claim 1,

wherein the identity information of the UE is a Cell-Radio Network Temporary Identifier (C-RNTI) Medium Access Control (MAC) control element which indicates C-RNTI of the UE, the random access procedure is initiated by the UE, and

wherein, when the PDCCH is received through the primary carrier, indicates the C-RNTI of the UE, and includes second uplink grant information for new data transmission, the contention resolution procedure is considered as a successful procedure.

4. The method according to claim 3, wherein the UE considers whether the PDCCH is received through the primary carrier in order to determine whether the contention resolution procedure is successful only when the UE transmits the third message including the C-RNTI MAC control element to the eNB.

5. The method according to claim 1,

wherein the identity information of the UE is a Cell-Radio Network Temporary Identifier (C-RNTI) Medium Access Control (MAC) control element which indicates C-RNTI of the UE, the random access procedure is initiated by a command of the eNB, and

wherein, when the PDCCH is received through the primary carrier and indicates the C-RNTI of the UE, the contention resolution procedure is considered as a successful procedure.

6. The method according to claim 5, wherein when the PDCCH is received through the primary carrier and indicates the C-RNTI of the UE, the contention resolution procedure is considered as a successful procedure in a case in which the PDCCH includes second UL grant information and in a case in which the PDCCH includes downlink assignment information.

7. The method according to claim 1, wherein the identity information of the UE is a UE contention resolution identity Medium Access Control (MAC) control element which includes an identifier other than a Cell-Radio Network Temporary Identifier (C-RNTI) of the UE, and

wherein, when the PDCCH is received through the primary carrier and indicates temporary C-RNTI of the UE, and a Physical Downlink Shared Channel (PDSCH) corresponding to the PDCCH includes the UE contention resolution identity MAC control element, a contention resolution procedure is considered as a successful procedure.

8. The method according to claim 1, wherein the UE performs a HARQ operation through the one or more secondary carriers, independently of transmission of the third message and reception of the PDCCH.

9. The method according to claim 1, wherein the primary carrier is a standalone carrier that is usable without the one or more secondary carriers, and each of the one or more secondary carriers is an additional carrier that is not usable without the primary carrier.

10. A UE which performs random access to an evolved NodeB (eNB) in a mobile communication system supporting carrier aggregation using a primary carrier and one or more secondary carriers, the UE comprising:

a Medium Access Control (MAC) layer module including a plurality of HARQ entities respectively corresponding to the plurality of component carriers, and configured to control signal transmission and reception using the primary carrier or the one or more secondary carriers; and

a processor functionally connected to the MAC layer module and including a physical layer module configured to transmit and receive a signal through the primary carrier or the one or more secondary carriers,

wherein only when a Physical Downlink Control Channel (PDCCH) indicated by identity information of the UE is received through the primary carrier used to transmit a message to the eNB, the processor considers a contention resolution procedure according to transmission of the message as a successful procedure, and

wherein when the PDCCH is received through the one or more secondary carriers, the processor considers the contention resolution procedure as an unsuccessful procedure.

11. The UE according to claim 10, wherein the MAC layer module is further configured to determine whether the contention resolution procedure is successful only when the physical layer module reports reception of the PDCCH through the primary carrier to the MAC layer module.

12. The UE according to claim 10, wherein the message is identity information of the UE and includes a Cell-Radio Network Temporary Identifier (C-RNTI) Medium Access Control (MAC) control element which indicates C-RNTI of the UE, and the processor considers the contention resolution procedure as a successful procedure when the random access procedure is initiated by the UE, the PDCCH is received through the primary carrier, indicates the C-RNTI of the UE, and includes uplink grant information for new data transmission.

13. The UE according to claim 12, wherein the processor considers whether the PDCCH is received through the primary carrier or not in order to determine whether the contention resolution procedure is successful only when the third message including the C-RNTI MAC control element is transmitted to the eNB.

14. The UE according to claim 10, wherein the message is identity information of the UE and includes a Cell-Radio Network Temporary Identifier (C-RNTI) Medium Access Control (MAC) control element which indicates C-RNTI of the UE, and the processor considers the contention resolution procedure as a successful procedure when the random access procedure is initiated by a command of the eNB, and the PDCCH is received through the primary carrier and indicates the C-RNTI of the UE.

15. The UE according to claim 14, wherein when the PDCCH is received through the primary carrier and indicates the C-RNTI of the UE, the processor considers the contention resolution procedure as a successful procedure in a case in which the PDCCH includes uplink grant information and in a case in which the PDCCH includes downlink assignment information.

16. The UE according to claim 10, wherein the message is identity information of the UE and includes a UE contention resolution identity MAC control element including an identifier other than a Cell-Radio Network Temporary Identifier (C-RNTI) of the UE, and the processor considers the contention resolution procedure as a successful procedure when the PDCCH is received through the primary carrier and indicates temporary C-RNTI of the UE, and a Physical Downlink Shared Channel (PDSCH) corresponding to the PDCCH includes the UE contention resolution identity MAC control element.

17. The UE according to claim 10, wherein the UE performs a HARQ operation through the one or more secondary carriers, independently of transmission of the message and reception of the PDCCH.

18. The UE according to claim 10, wherein the primary carrier is a standalone carrier that is usable without the one or more secondary carriers, and each of the one or more secondary carriers is an additional carrier that is not usable without the primary carrier.