Provided are a method for transmitting a random access preamble in a narrowband-IoT system supporting time division duplexing and an apparatus therefor.

Specifically, a method for transmitting a narrowband physical random access channel (NPRACH) preamble by a user equipment in a narrowband-Internet of things (NB-IoT) system supporting time division duplexing may include: receiving, from a base station, configuration information related to an uplink-downlink configuration; and transmitting, to the base station, the NPRACH preamble configured by considering the uplink-downlink configuration.

A wireless device, such as an wireless access point, receives signals detected by a plurality of antennas of a wireless device to produce a plurality of antenna-specific receive signals potentially representing a wireless transmission received from each of one or a plurality of devices. A signal processing component of the wireless device, such as a modem, performs several operations on the antenna-specific receive signals, including building a first space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover a transmission from a first device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the first device, and building a second space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover a transmission from a second device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the second device.

Disclosed methods include transmitting an OFDM signal including a succession of frames spaced apart by a set of training symbols that are symmetric in time and each formed by a plurality of even-frequency sub-carriers, spaced by odd frequency zeros. The OFDM signal is received and sampled and timing metrics are determined. Local maximums, or peaks of the timing metrics are detected, and from the peaks a coarse time offset is determined. A correlation metric, at sample indexes within a region determined by the coarse time offset, is applied and, based on a peak, an estimated time offset is generated. A correlation metric of the estimated time offset is determined and, based on the correlation metric, an estimated frequency offset is generated.

Systems (400) and methods for removing dither introduced into a transmitted RF signal. The method comprising: receiving, by a receiver, the transmitted RF signal; converting, by the receiver, the transmitted RF signal into a discrete-time IF signal comprising a sequence of samples, where at least a first sample of said samples has a first sample duration different than a second sample duration of at least a second sample of said samples; and performing operations by a sub-sample dither removal device of the receiver to modify a sample timing of the discrete-time IF signal by decreasing or increasing the first sample duration of the first sample using a digital signal processing technique in a digital domain.

A method and apparatus for generating a preamble symbol in an Orthogonal Frequency Division Multiplexing (OFDM) system by generating a first main body sequence in a time domain by performing an inverse fast Fourier transform (IFFT) on a preset sequence in a frequency domain, generating a first postfix by copying samples in a preset section in the first main body sequence, generating a first prefix by copying samples in at least a portion of a section remaining by excluding the preset section from the first main body sequence, and generating a plurality of symbols, based on a combination of the first main body sequence, the first prefix, and the first postfix.

A method by which a terminal transmits a random access channel (RACH) signal in a wireless communication system comprises the step of transmitting the RACH signal to a base station according to an RACH format corresponding to a specific RACH subframe among previously defined RACH formats, wherein the method is configured such that a start point or an end point of the RACH signal in a time domain is differentiated according to whether a downlink control zone and an uplink control zone within the RACH subframe are punctured in a specific frequency band between the previously defined RACH formats.

This application relates to the field of communication technologies, and provides a communication method and apparatus, to improve demodulation performance. A first subcarrier spacing, a second subcarrier spacing, a CP length of a first symbol, and a CP length of a second symbol are determined, where the first subcarrier spacing is K times the second subcarrier spacing, K is an integer greater than 1, and the CP length of the first symbol is greater than or equal to the CP length of the second symbol.

Provided are a method and a device for transmitting and receiving uplink control information The method may include: receiving configuration information about a plurality of PUCCH resources allocated to the transmission of a plurality of UCIs in one slot; determining one PUCCH resource from among the plurality of PUCCH resources on the basis of the priority level of each of the plurality of UCIs; and multiplexing the plurality of UCIs with the one PUCCH resource and transmitting same.

Aspects of this disclosure relate transmitting and/or receiving reference symbols. A first reference symbol includes a symbol and a cyclically shifted portion of the symbol, where the cyclically shifted portion has cyclic shift length. A second reference symbol includes a cyclically shifted version of the first reference symbol that is cyclically shifted relative to the first reference symbol by the cyclic shift length. The first and second reference symbols are transmitted consecutively from at least one antenna.

A method for scheduling resources in a network where the scheduling activity is split across two nodes in the network is disclosed, comprising: receiving, from a local scheduler in a first radio access network, access network information at a global scheduler; accessing information regarding a second radio access network allocating, at the global scheduler, resources for secondary allocation by the local scheduler; applying a hash function to map the allocated resources for secondary allocation to a set of hash values; and sending, from the global scheduler, the set of hash values to the local scheduler.