Method and apparatus for performing cell search in wireless communication system

• US 10,673,671 B2
• Filed: 09/02/2016
• Issued: 06/02/2020
• Est. Priority Date: 09/02/2015
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yi, Yunjung, Kim, Bonghoe, Ko, Hyunsoo
• Primary Examiner(s): Nguyen, Anh Ngoc M
• Application Number:
  US15/756,495
• Publication Number:
  US 20180270008A1
• Time in Patent Office: 1,369 Days
• Field of Search: None
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• CPC Class Codes: H04L 27/2659 Coarse or integer frequency offset determination and synchronisation
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• 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
• CPC Class Codes: H04W 76/27 Transitions between radio resource control [RRC] states

Abstract

A method and apparatus for performing a cell search in a wireless communication system is provided. A narrowband user equipment (NB UE) performs the cell search at a specific frequency with a fixed frequency offset, and moves to the specific frequency with the fixed frequency offset and a channel raster.

Claims

1. A method performed by a narrowband user equipment (NB UE) in a wireless communication system, the method comprising:

receiving, from a network, frequency information including a fixed frequency offset and a channel raster,

wherein the frequency information is transmitted via a primary synchronization signal (PSS) or a secondary synchronization signal (SSS);

performing a cell search at a first frequency which is located apart from a specific frequency by the fixed frequency offset; and

receiving a physical broadcast channel (PBCH) on a second frequency which is located apart from the first frequency by the channel raster such that the second frequency is located apart from the specific frequency by frequency amount equal to the sum of the fixed frequency offset and the channel raster,

wherein the fixed frequency offset is 7.5 kHz and the channel raster is a multiple of 90 kHz, and

wherein a bandwidth less than 1.4 MHz is allocated to the NB UE.

2. The method of claim 1, wherein a fixed narrowband in a center frequency is configured for the NB UE.

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

a memory;

a transceiver; and

a processor, coupled to the memory and the transceiver, that;

controls the transceiver to receive, from a network, frequency information including a fixed frequency offset and a channel raster,

wherein the frequency information is transmitted via a primary synchronization signal (PSS) or a secondary synchronization signal (SSS);

performs a cell search at a first frequency which is located apart from the specific frequency by the fixed frequency offset; and

controls the transceiver to receive a physical broadcast channel (PBCH) on a second frequency which is located apart from the first frequency by the channel raster such that the second frequency is located apart from the specific frequency by frequency amount equal to the sum of the fixed frequency offset and the channel raster,

wherein the fixed frequency offset is set as 7.5 kHz and the channel raster is a multiple of 90 kHz, and

wherein a bandwidth less than 1.4 MHz is allocated to the NB UE.

4. The NB UE of claim 3, wherein a fixed narrowband in a center frequency is configured for the NB UE.