Method and apparatus for requesting transmission of synchronization signals in wireless communication system

• US 10,103,805 B2
• Filed: 09/21/2015
• Issued: 10/16/2018
• Est. Priority Date: 09/21/2014
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yi, Yunjung
• Primary Examiner(s): Thompson, Jr., Otis L
• Application Number:
  US15/512,436
• Publication Number:
  US 20170279522A1
• Time in Patent Office: 1,121 Days
• Field of Search: None
• CPC Class Codes: H04B 7/216 Code division or spread-spectrum multiple access [CDMA, SSMA]
• CPC Class Codes: H04B 7/26 at least one of which is mobile
• CPC Class Codes: H04B 7/2675 Frequency synchronisation
• CPC Class Codes: H04L 67/00 Network arrangements or protocols for supporting network services or applications user-to-user messaging H04L51/00; network arrangements, protocols or services for supporting real-time applications in data packet communications networks H04L65/00
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

A method and apparatus for requesting a synchronization signal in a wireless communication system is provided. A machine type communication user equipment (MTC UE) transmits a random access preamble for requesting the synchronization signal to a network, receives the synchronization signal from the network, and performs synchronization by using the received synchronization signal.

Claims

1. A method for performing synchronization in a wireless communication system, the method performed by a machine type communication user equipment (MTC UE) and comprising:

determining whether the MTC UE wakes up;

transmitting, to a network, a random access preamble requesting synchronization information when determining that the MTC UE wakes up;

receiving, from the network, the synchronization information together with system information in response to the random access preamble; and

performing the synchronization by using the received synchronization information and the system information,

wherein when the MTC UE is out-of-connection with the network for more than a specific threshold, the system information includes total system information, and

when the MTC UE is not out-of-connection with the network for more than the specific threshold, the system information includes only changes to the total system information.

2. The method of claim 1, wherein the random access preamble is a dedicated random access preamble.

3. The method of claim 2, wherein the dedicated random access preamble is configured via a physical broadcast channel (PBCH), a system information block (SIB), or higher layer signaling.

4. The method of claim 1, wherein the synchronization information consists of at least one of a primary synchronization signal (PSS) or a secondary synchronization signal (SSS).

5. The method of claim 1, wherein the synchronization information is received via 6 physical resource blocks (PRBs) at a center of a system bandwidth, in a dedicated subband or a previously used subband.

6. The method of claim 1, further comprising:

performing a cell search, before transmitting the random access preamble.

7. The method of claim 6, wherein performing the cell search comprises identifying whether the network supports the MTC UE or coverage enhancement.

8. The method of claim 6, wherein performing the cell search comprises identifying a cell identifier (ID).

9. The method of claim 1, further comprising:

receiving a random access response from the network as a response to the random access preamble, after performing the synchronization.

10. The method of claim 9, further comprising:

transmitting a message including uplink (UL) data to the network, after receiving the random access response.

11. The method of claim 10, wherein the message includes a cell radio network temporary identifier (C-RNTI).

12. A machine type communication user equipment (MTC UE) comprising:

a memory;

a transceiver; and

a processor coupled to the memory and the transceiver, said processor configured to;

determine whether the MTC UE wakes up;

control the transceiver to transmit, to a network, a random access preamble requesting synchronization information when determining that the MTC UE wakes up;

control the transceiver to receive, from the network, the synchronization information together with system information in response to the random access preamble; and

performs synchronization by using the received synchronization information and the system information,

wherein when the MTC UE is out-of-connection with the network for more than a specific threshold, the system information includes total system information, and

when the MTC UE is not out-of-connection with the network for more than the specific threshold, the system information includes only changes to the total system information.