A method for transmitting a random access preamble in a narrowband-IoT system supporting time division duplexing and an apparatus therefor. In some implementations, 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.

The present invention discloses a transmission method and apparatus for feedback information of uplink transmission. The method comprises: a terminal transmitting a physical uplink shared channel (PUSCH) in a special sub-frame m, where m is an integer; the terminal detecting, subsequent to the special frame m, in a sub-frame comprising downlink transmission resources or in a sub-frame m+k, a downlink control channel using an uplink/downlink control information (DCI) format, where k is a positive integer; and the terminal determining, according to the downlink control channel, whether to again transmit the PUSCH transmitted in the special sub-frame m. accordingly, the present invention provides a transmission solution that transmits PUSCH feedback information in a special sub frame, ensuring that the PUSCH transmitted in the special sub frame can normally obtain ACK/NACK feedback information.

A client device includes a processor and an antenna. The client device obtains an announcement that specifies a winning client of a channel contention competition; identifies a group association of the client device using an identity of the winning client; transmits a preamble modulated by an entry of a preamble interference nullification matrix, the entry is based on the group association; and transmits, after transmitting the preamble, a data transmission. The preamble is transmitted at the same time as a second preamble is transmitted by a second client device.

A preamble detection system and method includes converting the phase domain input samples corresponding to the preamble into frequency domain input samples. An I/Q-formatted dot product is generated from a dot product process between the frequency domain input samples and a reference pattern indicative of an expected preamble. The I/Q-formatted dot product is averaged with at least one previously generated I/Q-formatted dot product to generate an I/Q-formatted averaged dot product. The I/Q-formatted averaged dot product is converted into a polar-formatted averaged dot product, wherein the polar-formatted averaged dot product includes a magnitude of the polar-formatted averaged dot product and an angle of the polar-formatted averaged dot product. A preamble-found signal is then generated in response to the magnitude of the polar-formatted averaged dot product exceeding a preamble magnitude threshold.

A transport block size (TBS) of a first uplink message (RACH Msg3) transmitted on a Physical Uplink Shared Channel (PUSCH) during a random access procedure in a User Equipment (UE) accessing a radio access network may be determined by receiving a pathloss threshold parameter. A downlink pathloss value indicative of radio link conditions between the UE and a base station (eNB) serving the UE is then determined. A smaller value of TBS is selected from a set of TBS values if the determined pathloss value is greater than an operating power level of the UE minus the pathloss threshold parameter. A larger value of TBS is selected if the pathloss value is less than the operating power level of the UE minus the pathloss threshold parameter and the TBS required to transmit the RACH Msg3 exceeds the smaller TBS value.

A signal sending method and apparatus, and a signal receiving method and apparatus are provided, to ensure a low peak-to-average power ratio and a frequency domain diversity gain when a signal is sent on two different subcarrier groups in a same time cell. The method includes: mapping, by a transmit end, a first sequence {p.sub.ia.sub.0, p.sub.ia.sub.1, . . . , p.sub.ia.sub.P1} whose length is P into an i.sup.th subcarrier group in M subcarrier groups in a same time cell, where the i.sup.th subcarrier group includes K consecutive subcarriers that are evenly distributed, M, P, and K are all greater than or equal to 2, PK, there is at least one pair of two inconsecutive subcarrier groups in the M subcarrier groups, and a second sequence {p.sub.i} corresponding to the M subcarrier groups meets the following requirement: A sequence {x.sub.i} is a Barker sequence, where {x.sub.i}={x.sub.i|x.sub.1=p.sub.s+1, x.sub.2=p.sub.s+2, . . . , x.sub.Ms=p.sub.M, x.sub.Ms+1=p.sub.1, x.sub.Ms+2=p.sub.2, . . . , x.sub.M=p.sub.s}, or a sequence {cx.sub.i} is a second sequence corresponding to M consecutive subcarrier groups, where c is a non-zero complex number; generating, by the transmit end, a sending signal based on signals on subcarriers in the i.sup.th subcarrier group; and sending, by the transmit end, the sending signal.

A method for transmitting a random access preamble in a narrowband-IoT system supporting time division duplexing and an apparatus therefor. In some implementations, 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.

Provided in an embodiment of the present invention is a method for transmitting data via a sidelink. The method comprises: a scheduling terminal sends to a transmitting terminal a first physical control signal, wherein the first physical control signal comprises a first transmission resource used to transmit first-type system information; and the scheduling terminal sends to the transmitting terminal the first-type system information, wherein the first-type system information comprises sidelink resource pool information used for transmission via a sidelink between the transmitting terminal and a receiving terminal. In the embodiment of the present invention, a scheduling terminal can configure a sidelink transmission resource for a transmitting terminal, thereby significantly increasing success rates of D2D and V2V communication, reducing delay, and expanding the capacity of D2D and V2V communication.

A method in a node is disclosed. The method comprises receiving a signal, and obtaining a first oversampled received signal by sampling the received signal according to a symbol rate. The method further comprises estimating a first frequency offset based on the first oversampled received signal, the first frequency offset estimated using an estimation range limited to one of a bandwidth of the received signal or the symbol rate of the received signal, and obtaining a second oversampled received signal by sampling the received signal according to N times the symbol rate, wherein N is greater than 1. The method further comprises estimating a true frequency offset based on the first frequency offset estimate and the second oversampled received signal.

A method and an apparatus for establishing a user equipment cooperation group are provided. The method includes: receiving, by a neighboring user equipment (NUE), a first message sent by a target user equipment (TUE), where the first message include s a first preamble sequence and a data part of the TUE, and the first preamble sequence is used for random access between the TUE and the NUE; determining, by the NUE, the TUE based on the data part of the TUE; sending, by the NUE, a second message to a base station, where the second message includes a second preamble sequence and the data part of the NUE, and the second preamble sequence is used for random access between the NUE and the base station; and receiving, by the NUE, a third message sent by the base station, where the third message includes a user equipment cooperation group identifier