The present disclosure provides a method for transmitting a demodulation reference signal. Specifically, the method performed by the terminal comprising: receiving, from a base station, a radio resource control (RRC) signaling including control information representing that transform precoding for an uplink is enabled; generating a low peak to average power ratio (PAPR) sequence based on a length-6 sequence; generating a sequence used for the demodulation reference signal based on the low PAPR sequence; and transmitting, to the base station, the demodulation reference signal based on the sequence used for the demodulation reference signal, wherein the length-6 sequence has an 8-Phase Shift Keying (PSK) symbol as each element of the sequence.

Method for generating an OFDM training sequence, device and computer program product. The OFDM training sequence consists of at least two OFDM symbols, and the OFDM training sequence comprises at least two OFDM sub-carriers, the method comprising a step of partitioning the OFDM sub-carriers into at least two separate groups comprising at least one sub-carrier, a number of groups being smaller than a number of sub-carriers. The method comprises steps, carried out independently for each group, of generating an elementary sequence associated with a group by combining the sub-carriers of the group, the elementary sequence having a duration equal to a duration of one of the at least two symbols.

Satellites in a non-terrestrial network may provide positioning reference signals (PRS) to user equipment (UE), with which the UE may determine its position using propagation delay difference measurements, such as Time Difference of Arrival (TDOA) measurement. Due to the large distances between satellites and the UE, the propagation delay differences in the PRS received from satellites may exceed half a radio frame, resulting in a frame level timing ambiguity in the differential measurements. The satellites transmit secondary PRS, along with primary PRS, that include timing information to resolve frame level timing ambiguity of the primary PRS. The positioning occasions in the secondary PRS, for example, may be aligned with corresponding positioning occasions primary PRS within each radio frame, and are transmitted with a periodicity that is an integer multiple (greater than 1) of that of the primary PRS to resolve the frame level timing ambiguity of the primary PRS.

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for transmitting sounding reference signal (SRS) resources with frequency hopping. In some implementations, a user equipment (UE) may use different SRS ports, different antenna ports, different numbers and sizes of SRS resources, different periodicities, different offsets, different transmission comb values, different number of symbols, different power control parameters, and/or different transmission comb offset values for SRS transmissions on different frequency subbands of the frequency hopping pattern to ensure that sounding operations cover all antennas of the UE, cover the entire frequency range of interest, and provide sufficiently dense SRS transmissions from which a base station can determine the best channel for DL transmissions while also using a minimum amount of SRS resources and consuming minimal power in the UE.

Disclosed are a method and an apparatus for generating an STF signal usable in a wireless LAN system. The STF signal is included in a field used to improve AGC estimation of a MIMO transmission. A portion of the STF signal is used to transmit an uplink, and can be used for uplink MU PPDUs transmitted from a plurality of STAs. The STF signal that is disclosed, for example, is used for a 40 MHz band or an 80 MHz band, is desirably usable for the 40 MHz band, and can be generated based on a sequence in which a predetermined M sequence is repeated. The predetermined M sequence can be a binary sequence of which the length is 15 bits.

OFDM-BPSK symbol sequences are used for mutual-coupling based phase array calibration. Such substitution allows phase to be estimated more accurately using a given estimation duration without compromising other estimates' (amplitude and group delay) accuracies.

An embodiment method for managing uplink transmission includes dividing, by a network controller, frequency resources in a single OFDM symbol into two sets of frequency resources. The method further includes signaling, by the network controller, to a UE to transmit data in a first set of the frequency resources and to transmit a pilot signal in a second set of the frequency resources.

A reference signal sending method, a reference signal receiving method, and an apparatus are provided. A first network device determines a first resource. The first network device generates a reference signal corresponding to the first resource. The reference signal includes M parts, and all of the M parts are the same. The first resource does not carry a cyclic postfix of the reference signal. Alternatively, the first resource carries a cyclic prefix of the reference signal and the cyclic prefix corresponding to the reference signal is located only at the start of the 1.sup.st part in the M parts. M is a positive integer. The first network device sends the reference signal to a second network device on the first resource.

Provided is a transmitter which improves the flexibility of SRS resource allocation without increasing the amount of signaling for notifying the cyclic shift amount. In the transmitter, with regard to each basic shift amount candidate group having a basic shift amount from 0 to N−1, a transmission control unit (206) specifies the actual shift amount imparted to a cyclic shift sequence used in scrambling a reference signal transmitted from each antenna port, said specification being performed based on a table in which cyclic shift amount candidates correspond to each antenna port, and based on setting information transmitted from a base station (100). With regard to basic shift amount candidates for shift amount X, the table differentiates between an offset pattern comprising offset values for cyclic shift amount candidates corresponding to each antenna port and an offset pattern corresponding to basic shift amount candidates of X+N/2.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may identify a gap period following a downlink portion of a time division duplexing (TDD) frame. The UE may selectively perform, based at least in part on the gap period, a clear channel assessment (CCA) on a channel of a radio frequency spectrum band. The UE may transmit at least one of a sounding reference signal (SRS) or a physical random access channel (PRACH) preamble in a set of initial symbols of an uplink portion of the TDD frame following the gap period, wherein the SRS or PRACH preamble is frequency-domain multiplexed during the set of initial symbols with one or more of: a demodulation reference signal (DMRS), an uplink data transmission, an uplink control transmission, or a random access transmission.