Method for transmitting signal for MTC and apparatus for same

• US 10,165,602 B2
• Filed: 11/14/2017
• Issued: 12/25/2018
• Est. Priority Date: 07/26/2013
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yang, Suckchel, Ahn, Joonkui, Yi, Yunjung, You, Hyangsun, Kim, Bonghoe
• Primary Examiner(s): Patel, Jay P
• Application Number:
  US15/812,582
• Publication Number:
  US 20180070385A1
• Time in Patent Office: 406 Days
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A method is provided for performing a random access procedure by a user equipment (UE) in a wireless communication system supporting coverage enhancement. The UE repeatedly transmits a physical random access channel (PRACH) signal, determines a random access radio network temporary identifier (RA-RNTI) corresponding to the PRACH signal using system frame number (SFN) information, wherein time index information and frequency index information are not used for determining the RA-RNTI, and monitors downlink control information masked by the determined RA-RNTI. The time index information indicates a subframe starting the repeated transmission of the PRACH signal, the frequency index information indicates a frequency index of the PRACH signal transmitted in the starting subframe, and the SFN information indicates a radio frame starting the repeated transmission of the PRACH signal.

Claims

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

repeatedly transmitting, by the UE, a physical random access channel (PRACH) signal;

determining, by the UE, a random access radio network temporary identifier (RA-RNTI) corresponding to the PRACH signal using system frame number (SFN) information, wherein time index information and frequency index information are not used for determining the RA-RNTI; and

monitoring, by the UE, downlink control information masked by the determined RA-RNTI,

wherein the time index information indicates a subframe starting the repeated transmission of the PRACH signal, the frequency index information indicates a frequency index of the PRACH signal transmitted in the starting subframe, and the SFN information indicates a radio frame starting the repeated transmission of the PRACH signal.

2. The method according to claim 1, wherein the monitoring the downlink control information is performed in a random access response (RAR) window, the RAR window indicating a time interval for detecting the RA-RNTI and receiving a random access response, and

wherein a start subframe of the RAR window is determined by adding a specific subframe offset to a subframe ending the repeated transmission of the PRACH signal.

3. The method according to claim 2, wherein the specific subframe offset is 3 subframes.

4. The method according to claim 1, wherein a number of repetitions for transmitting the PRACH signal is determined based on a reference signal received power (RSRP) measurement.

5. The method according to claim 1, further comprising:

receiving system information comprising information about random access response (RAR) window sizes, the RAR window sizes being independently configured for a plurality of PRACH resources configured for the UE,

wherein a size of the RAR window is determined as a RAR window size configured for a PRACH resource used for transmitting the PRACH signal.

6. The method according to claim 1, wherein a time interval for the repeated transmission of the PRACH signal is extended over a plurality of radio frames.

7. The method according to claim 6, wherein each radio frame comprises 10 subframes.

8. A user equipment (UE) for performing a random access procedure in a wireless communication system supporting coverage enhancement, the UE comprising:

a transceiver; and

a processor operatively connected to the transceiver and configured to;

control the transceiver to repeatedly transmit a physical random access channel (PRACH) signal,

determine a random access radio network temporary identifier (RA-RNTI) corresponding to the PRACH signal using system frame number (SFN) information, wherein time index information and frequency index information are not used for determining the RA-RNTI, and

monitor downlink control information masked by the determined RA-RNTI,

wherein the time index information indicates a subframe starting the repeated transmission of the PRACH signal, the frequency index information indicates a frequency index of the PRACH signal transmitted in the starting subframe, and the SFN information indicates a radio frame starting the repeated transmission of the PRACH signal.

9. The UE according to claim 8, wherein the processor monitors the downlink control information in a random access response (RAR) window, the RAR window indicating a time interval for detecting the RA-RNTI and receiving a random access response, and

wherein the processor determines a start subframe of the RAR window by adding a specific subframe offset to a subframe ending the repeated transmission of the PRACH signal.

10. The UE according to claim 9, wherein the specific subframe offset is 3 subframes.

11. The UE according to claim 8, wherein a number of repetitions for transmitting the PRACH signal is determined based on a reference signal received power (RSRP) measurement.

12. The UE according to claim 8, wherein the processor receives system information comprising information about random access response (RAR) window sizes, the RAR window sizes being independently configured for a plurality of PRACH resources configured for the UE, and

wherein the processor determines a size of the RAR window as a RAR window size configured for a PRACH resource used for transmitting the PRACH signal.

13. The UE according to claim 8, wherein a time interval for the repeated transmission of the PRACH signal is extended over a plurality of radio frames.

14. The UE according to claim 13, wherein each radio frame comprises 10 subframes.