An initial access indication method includes: carrying flag information in a Synchronization Signal Block (SSB), the flag information indicating whether an initial access bandwidth corresponding to the SSB supports the access of a first type user equipment (UE).

Doppler pre-compensation is performed on synchronization signals using each of multiple Doppler pre-compensation patterns to generate a plurality of sets of Doppler pre-compensated synchronization signals that are transmitted using one or more beams. A signal indicating the Doppler pre-compensation patterns used is transmitted in one of a system information block (SIB) or a radio resource control (RRC) reconfiguration message, in connection with initial access by a user equipment (UE), idle UE cell reselection, connected UE data channel reception, or UE handover. The signal indicates Doppler pre-compensation patterns for a transmitting cell and Doppler pre-compensation patterns for one or more neighbor cells. The synchronization signal comprises a synchronization signal block (SSB) including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). Received Doppler pre-compensated synchronization signals are combined in the time domain in connection with timing synchronization detection, frequency offset (FO) estimation, or reference signal received power (RSRP) measurement.

Embodiments of the present invention relate to a method and a system for controlling phase synchronization, and an apparatus. The method includes: determining a path from a non-reference base station to a preset reference base station, obtaining a first phase difference between every two adjacent base stations on the path, obtaining a second phase difference between the reference base station and the non-reference base station according to the first phase difference, and adjusting a non-reference phase of the non-reference base station to a reference phase of the reference base station according to the second phase difference. According to the method and system for controlling phase synchronization, and the apparatus that are provided in the embodiments of the present invention, in a single-frequency network system, phases of base stations are synchronized without a need to install a GPS antenna, so that system costs are reduced.

This closure relates to narrowband communication supporting an Internet of Things (IoT) service in a next-generation wireless communication system and, more particularly, to a method and apparatus for transmitting and receiving narrowband synchronization signals. A base station transmits a narrowband secondary synchronization signal indicating a narrowband cell identity, a specific sequence generated by performing phase rotation with respect to a base sequence generated through a second Zadoff-Chu sequence having a predetermined length L in a frequency domain and multiplying the base sequence by a cover sequence in element units is used for the narrowband secondary synchronization signal, and a specific root index is selected from among M (M<L) root indices as a root index of the second Zadoff-Chu sequence and the specific root index is selected in a range from k to k+M−1 in terms of a predetermined offset k.

A method and user equipment (UE) for recovering a service in a wireless network is provided. The method includes detecting, in a UE, that a fast cell update criteria is met, and recovering, in the UE, the service in the wireless network by performing a cell update procedure.

Aspects of the present disclosure provide techniques and apparatus for performing narrowband physical random access channel (PRACH) procedures in large cells. For example, aspects of the present disclosure provide techniques for narrowband PRACH procedures (e.g., narrowband internet of things (NB-IoT)) to accommodate larger RTTs (e.g., up to 100 km). In some cases, supporting larger RTTs may involve a base station altering its PRACH processing by performing a two-step process of, first, obtaining a frequency domain phase offset based on an uplink signal from a UE, which provides a fractional delay and, second, performing a time domain correlation for different timing hypotheses to determine a timing offset based on the uplink signal. Supporting larger RTTs may also involve enabling a new NPRACH format that may coexist with legacy 3.75 kHz resources.

In the present invention, a method for synchronizing frequency and time in a wireless communication system and an apparatus for supporting the same are disclosed. Particularly, a method for synchronizing frequency and time performed by a terminal in a wireless communication system may include receiving a specific signal including a PSS, compensating the specific signal with at least one time offset candidate, generating at least one first differentiation value, generating at least one second differentiation value, calculating a cross correlation value between the at least one first differentiation value and the at least one second differentiation value, and estimating a time offset and a frequency offset of the PSS based on a time offset candidate that corresponds to a greatest cross correlation value among at least one cross correlation value calculated for at least one time offset candidate.

An out-of-synchronization processing method implemented in an intermediate communication apparatus includes obtaining synchronization information for synchronizing with a downstream communication apparatus, and performing a search for an upstream communication apparatus and a communication with the downstream communication apparatus. A parameter is adjusted according to the synchronization information during the communication with the downstream communication apparatus.

Various aspects provide for communicating a first set of broadcast reference signals (RSs) in a first subframe that includes a synchronization (SYNC) channel and communicating a second set of broadcast RSs in a second subframe that follows the first subframe. The second subframe may immediately follow the first subframe. A portion of the SYNC channel may include information indicating a configuration of broadcast RSs in one or more other subframes. The broadcast RSs may be configured for timing-error estimation, frequency-error estimation, and/or channel estimation. Additional and alternative aspects, embodiments, and features are also provided herein.

According to one embodiment, a synchronization circuit includes a received-signal detecting unit which detects a received signal including a first and a second reference signal, a timing-synchronization adjusting unit including a storage module storing information of the first reference signal and a correlation operating module carrying out correlation operation of the first reference signal included in the received signal and the information of the first reference signal output from the storage module, the timing-synchronization adjusting unit which carries out timing synchronization so that a result of the correlation operation carried out by the correlation operating module becomes a predetermined value, and a phase-synchronization adjusting unit which carries out phase synchronization of a subcarrier by adjusting a component varied depending on a phase of a subcarrier frequency by using a phase modulation signal included in the second reference signal, wherein the received signal is a filtered multicarrier signal.