METHOD FOR A USER TERMINAL TO RANDOM ACCESS A CARRIER AGGREGATION MOBILE COMMUNICATION SYSTEM

• US 20120076104A1
• Filed: 06/07/2010
• Published: 03/29/2012
• 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
• Granted Patent: US 8,861,460 B2
• Time in Patent Office: Days
• 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 by a User Equipment (UE) for an eNB in a mobile communication system using carrier aggregation in which communication is conducted using a plurality of component carriers, the method comprising:

transmitting a random access preamble to the eNB through a first uplink component carrier (hereinafter referred to as ‘

UL CC’

) from among a plurality of UL CCs;

receiving a random access response message including first uplink (UL) grant information as a response to the random access preamble through a first downlink component carrier (hereinafter referred to as ‘

DL CC’

) corresponding to the first UL CC;

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 in the first UL CC; and

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

wherein the UE considers a contention resolution procedure according to transmission of the third message as a successful procedure only when the PDCCH is received through the first DL CC.

2. The method according to claim 1, wherein the UE does not consider the PDCCH as a contention resolution message according to transmission of the third message when the PDCCH is received through a second DL CC different from the first DL CC.

3. The method according to claim 1, wherein the UE includes a physical layer module and a Medium Access Control (MAC) module, and the MAC layer module determines whether a contention resolution procedure according to transmission of the third message is successful or not only when the physical layer module reports reception of the PDCCH through the first DL CC to the MAC layer module.

4. The method according to claim 1, wherein the identity information of the UE is a C-RNTI MAC control element which indicates C-RNTI of the UE, the random access procedure is initiated by the UE, and when the PDCCH is received through the first DL CC, indicates the C-RNTI of the UE, and includes second uplink grant information for new data transmission, the contention resolution procedure according to transmission of the third message is considered as a successful procedure.

5. The method according to claim 1, wherein the identity information of the UE is a C-RNTI MAC control element which indicates C-RNTI of the UE, the random access procedure is initiated by a command of the eNB, and when the PDCCH is received through the first DL CC and indicates the C-RNTI of the UE, the contention resolution procedure according to transmission of the third message is considered as a successful procedure.

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

7. The method according to claim 1, wherein the identity information of the UE is a UE contention resolution identity MAC control element which includes an identifier other than the C-RNTI of the UE, and when the PDCCH is received through the first DL CC and indicates temporary C-RNTI of the UE, and a PDSCH corresponding to the PDCCH includes the UE contention resolution identity MAC control element, a contention resolution procedure according to transmission of the third message is considered as a successful procedure.

8. The method according to claim 7, wherein the UE considers whether the PDCCH is received through the first DL CC in order to determine whether the contention resolution procedure according to transmission of the third message is successful only when the UE transmits the third message including the C-RNTI MAC control element to the eNB.

9. The method according to claim 1, wherein the UE performs a HARQ operation through a second UL CC different from the first UL CC and a second DL CC different from the first DL CC, independently of transmission of the third message and reception of the PDCCH.

10. A UE which performs random access to an eNB in a mobile communication system using carrier aggregation in which communication is conducted using a plurality of component carriers, the UE comprising:

a MAC layer module including a plurality of HARQ entities respectively corresponding to the plurality of component carriers, and configured to control signal transmission using a plurality of uplink component carriers (referred to as ‘

UL CCs’

) through the plurality of HARQ entities and signal reception through a plurality of downlink component carriers (referred to as ‘

DL CCs’

) respectively corresponding to the plurality of UL CCs; and

a processor functionally connected to the MAC layer module and including a physical layer module configured to transmit a signal through the plurality of UL CCs and to receive a signal through the plurality of DL CCs,

wherein only when a Physical Downlink Control Channel (PDCCH) indicated by identity information of the UE is received through a first DL CC corresponding to a first UL CC used to transmit a third message to the eNB from among the plurality of UL CC, the processor considers a contention resolution procedure according to transmission of the third message as a successful procedure.

11. The UE according to claim 10, wherein the processor is configured such that the processor does not consider a PDCCH received through a second DL CC different from the first DL CC as the contention resolution message according to transmission of the third message.

12. The UE according to claim 10, wherein the MAC layer module is configured to determine whether the contention resolution procedure according to transmission of the third message is successful or not only when the physical layer module reports reception of the PDCCH through the first DL CC to the MAC layer module.

13. The UE according to claim 10, wherein the third message is identity information of the UE and includes a C-RNTI MAC control element which indicates C-RNTI of the UE, and the processor considers the contention resolution procedure according to transmission of the third message as a successful procedure when the random access procedure is initiated by the UE, the PDCCH is received through the first DL CC, indicates the C-RNTI of the UE, and includes uplink grant information for new data transmission.

14. The UE according to claim 10, wherein the third message is identity information of the UE and includes a C-RNTI MAC control element which indicates C-RNTI of the UE, and the processor considers the contention resolution procedure according to transmission of the third message as a successful procedure when the random access procedure is initiated by a command of the eNB, and the PDCCH is received through the first DL CC and indicates the C-RNTI of the UE.

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

16. The UE according to claim 10, wherein the third message is identity information of the UE and includes a UE contention resolution identity MAC control element including an identifier other than the C-RNTI of the UE, and the processor considers the contention resolution procedure according to transmission of the third message as a successful procedure when the PDCCH is received through the first DL CC and indicates temporary C-RNTI of the UE, and a PDSCH corresponding to the PDCCH includes the UE contention resolution identity MAC control element.

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

18. The UE according to claim 10, wherein the UE performs a HARQ operation through a second UL CC different from the first UL CC and a second DL CC different from the first DL CC, independently of transmission of the third message and reception of the PDCCH.