# US 11,115,144 B2 · Cell search method in wireless communication system and apparatus therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,144 B2 - Document ID: US11115144B2 - Status: Granted - Kind: B2 - Application number: 16/738,724 - Filed: 2020-01-09 - Published: 2020-05-14 - Granted: 2021-09-07 - Earliest claimed: 2015-09-15 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Seokmin Shin; Yunjung Yi; Seonwook Kim; Bonghoe Kim - Web page: https://patentgrep.com/patent/US11115144B2 ## CPC - 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)} - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 12/189: {in combination with wireless systems (selective distribution or broadcast in wireless communication networks H04W4/06)} - H04L 27/2613: {Structure of the reference signals} - H04L 27/2692: {with preamble design, i.e. with negotiation of the synchronisation sequence with transmitter or sequence linked to the algorithm used at the receiver} - H04W 56/001: {Synchronization between nodes} - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04L 27/26132: {using repetition} - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A cell search method of a terminal in a wireless communication system, comprises: a step of receiving a narrow band synchronization signal through a narrow band from a base station; and a step of acquiring time synchronization and frequency synchronization with the base station on the basis of the narrow band synchronization signal and detecting an identifier of the base station, wherein the narrow band has a system bandwidth of 180 kHz and includes twelve carriers arranged at intervals of 15 kHz, and the narrow band synchronization signal consists of a first narrow band synchronization signal and a second narrow band synchronization signal, wherein the first narrow band synchronization signal can be transmitted in a sixth subframe of a radio frame and the second narrow band synchronization signal can be transmitted in a tenth subframe of the radio frame. ## Claims ### Claim 1 A method of performing, by a user equipment (UE), cell search in a wireless communication system, the method comprising: receiving, from a base station (BS), a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS); and acquiring time synchronization and frequency synchronization with the BS and detecting an identifier of the BS based on the NPSS and the NSSS, wherein the NPSS is transmitted in a sixth subframe of a each frame of a plurality of frames, and wherein the NSSS is transmitted in a tenth subframe of a every other frame of the plurality of frames. ### Claim 2 (depends on 1) The method of claim 1, wherein the NPSS and the NSSS are not transmitted in at least one symbol in which a reference signal (RS) is transmitted among symbols of the sixth subframe and the tenth subframe. ### Claim 3 (depends on 1) The method of claim 1, wherein the sixth subframe and the tenth subframe are subframes not configured as a multicast broadcast single frequency network (MBSFN) subframe. ### Claim 4 (depends on 1) The method of claim 1, wherein transmission periods of the NPSS and the NSSS are differently configured. ### Claim 5 (depends on 4) The method of claim 4, wherein: the transmission period of the NPSS is set to 10 ms, and the transmission period of the NSSS is set to 20 ms. ### Claim 6 (depends on 1) The method of claim 1, wherein the NPSS and the NSSS are generated using a Zadoff-Chu (ZC) sequence. ### Claim 7 (depends on 1) The method of claim 1, wherein the NPSS and the NSSS are transmitted through 11 orthogonal frequency-division multiple access (OFDMA) symbols. ### Claim 8 (depends on 1) The method of claim 1, wherein the NSSS is transmitted through 12 subcarriers in the tenth subframe. ### Claim 9 (depends on 1) The method of claim 1, wherein the UE operates in an in-band system, and wherein the NPSS and the NSSS are transmitted through a narrowband (NB) including 12 carriers spaced with 15 kHz. ### Claim 10 A user equipment (UE) performing cell search in a wireless communication system, the UE comprising: a transceiver configured to transmit and receive a radio signal; and a processor configured to control the transceiver, wherein the processor is further configured to: receive, from a base station (BS), a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS), and acquire time synchronization and frequency synchronization with the BS, and detect an identifier of the BS based on the NPSS and the NSSS, wherein the NPSS is transmitted in a sixth subframe of a each frame of a plurality of frames, and wherein the NSSS is transmitted in a tenth subframe of a every other frame of the plurality of frames. ### Claim 11 (depends on 10) The UE of claim 10, wherein the NPSS and the NSSS are not transmitted in at least one symbol in which a reference signal (RS) is transmitted among symbols of the sixth subframe and tenth subframe. ### Claim 12 (depends on 10) The UE of claim 10, wherein the sixth subframe and the tenth subframe are subframes not configured as a multicast broadcast single frequency network (MBSFN) subframe. ### Claim 13 (depends on 10) The UE of claim 10, wherein: a transmission period of the NPSS is set to 10 ms, and a transmission period of the NSSS is set to 20 ms. ### Claim 14 (depends on 10) The UE of claim 10, wherein the NPSS and the NSSS are transmitted through 11 orthogonal frequency-division multiple access (OFDMA) symbols. ### Claim 15 (depends on 10) The UE of claim 10, wherein the NSSS is transmitted through 12 subcarriers in the tenth subframe.