METHOD AND APPARATUS FOR PERFORMING RANDOM ACCESS PROCEDURE FOR COVERAGE ENHANCEMENT USER EQUIPMENTS IN WIRELESS COMMUNICATION SYSTEM

• US 20160262186A1
• Filed: 12/01/2014
• Published: 09/08/2016
• Est. Priority Date: 12/04/2013
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: LEE, Jaewook, PARK, Sungjun, LEE, Youngdae, JUNG, Sunghoon
• Granted Patent: US 9,955,508 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/00 Arrangements for detecting or preventing errors in the information received correcting synchronisation H04L7/00
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/189 Transmission or retransmission of more than one copy of a message
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A method and apparatus for performing a random access procedure in a wireless communication system is provided. In one embodiment, a user equipment (UE) determines a required amount of repetitions for uplink transmissions during a random access procedure, and performs repetitions for uplink transmissions based on the determined required amount of repetitions for uplink transmissions. The uplink transmissions may include transmission of preambles which are grouped. In another embodiment, a UE configures a communication windows for lost-cost machine-type communication (MTC) UE, and performs a random access procedure through the configured communication window.

Claims

1. A method for performing, by a user equipment (UE), a random access procedure in a wireless communication system, the method comprising:

determining a required amount of repetitions for uplink transmissions during a random access procedure; and

performing repetitions for uplink transmissions based on the determined required amount of repetitions for uplink transmissions.

2. The method of claim 1, wherein the required amount of repetitions is determined based on downlink channel condition or a number of repetitions for correct reception of a downlink message.

3. The method of claim 2, wherein a mapping relationship between the number of repetitions for correct reception of the downlink message or the downlink channel conditition, and an estimated number of repetitions for uplink transmissions is provided by a network.

4. The method of claim 2, wherein the downlink message is one of system information or a paging message.

5. The method of claim 1, wherein the required amount of repetitions is determined based on an amount of repetitions which was required for latest uplink transmissions.

6. The method of claim 1, wherein the uplink transmissions include transmission of preambles which are grouped.

7. The method of claim 6, wherein the preambles are grouped based on downlink channel condition or a number of repetitions for correct reception of a downlink message, or an amount of repetitions which was required for latest uplink transmissions.

8. A user equipment (UE) in a wireless communication system, the UE comprising:

a radio frequency (RF) unit for transmitting or receiving a radio signal; and

a processor coupled to the RF unit, and configured to;

determine a required amount of repetitions for uplink transmissions during a random access procedure; and

perform repetitions for uplink transmissions based on the determined required amount of repetitions for uplink transmissions.

9. A method for performing, by a user equipment (UE), a random access procedure in a wireless communication system, the method comprising:

configuring a communication windows for lost-cost machine-type communication (MTC) UE; and

performing a random access procedure through the configured communication window.

10. The method of claim 9, wherein a size of the configured communication window is fixed or configured by a network.

11. The method of claim 9, wherein the performing the random access procedure comprises:

performing repetitions for uplink transmissions within the configured communication window.

12. The method of claim 11, wherein a first repetition among the repetitions for uplink transmissions is performed in a designated subframe.

13. The method of claim 11, wherein the performing the random access procedure comprises:

monitoring a downlink response message in a next communication window after performing the repetitions for uplink transmission within the configured communication window.

14. The method of claim 9, wherein the performing the random access procedure comprises:

selecting the configured communication window randomly.

15. The method of claim 9, wherein the performing the random access procedure comprises:

performing a backoff in a unit of the configured communication windows if the UE fails to transmit an uplink message within the configured communication window or the UE fails to receive a downlink response message.