Methods, systems, and devices for wireless communications are described. A device (e.g., a base station or a user equipment (UE)) may identify a sequence length corresponding to a number of resource blocks, and select a modulation scheme based on the sequence length. The device may select, from a set of sequences associated with the modulation scheme, a sequence having the sequence length. In some examples, the set of sequences may include at least one of a set of time domain phase shift keying computer-generated sequences or a set of frequency domain phase shift keying computer-generated sequences. The device may generate a reference signal for a data transmission based on the sequence and transmit the reference signal within the number of resource blocks.

Methods, systems, and devices for wireless communications are described. A base station may associate a first port and a second port each with a set of antenna elements based on a first and a second linear precoding vector, where the phases of the ports are coherent. The base station may generate coefficients indicating a first combination and a second combination of a first data set for a first user equipment (UE) and a second data set for a second UE. In some cases, the base station may apply the first linear precoding vector to the first combination, apply the second linear precoding vector to the second combination, and transmit the first combination using a first transmission beam corresponding to the first port and the second combination using a second transmission beam corresponding to the second port to the first and second UEs.

A transmission device includes: a reference sequence obtaining unit that obtains a reference sequence having a symbol sequence length equal to or smaller than a modulation order in a modulation method used for data transmission, the reference sequence having a constant amplitude in a time domain and a frequency domain; and a multiplexing unit that transmits a signal including the reference sequence.

An RF PNT system may include LORAN stations. Each LORAN station may include a LORAN antenna, and a LORAN transmitter coupled to the LORAN antenna and configured to transmit a series of LORAN PNT RF pulses having a time spacing between adjacent LORAN PNT RF pulses. One or more of the LORAN stations may include a message embedding generator coupled to the LORAN transmitter and configured to generate message RF bursts based upon an input message, and with each message RF burst being in the time spacing between respective adjacent LORAN PNT RF pulses.

Methods and systems for hardware-efficient carrier sensing are disclosed. The method may include receiving a received signal during a detection window, generating a phase-discriminated waveform based on the received signal, determining a plurality of absolute values respectively based on a plurality of correlations of the phase-discriminated waveform, and generating a detection metric based on a peak value of the plurality of absolute values.

Systems and methods are directed to low cost and low power carrier frequency offset (CFO) estimation in a receiver. In-phase (I) and quadrature (Q) samples of a wireless signal are received by the receiver and a first phase and a second phase are extracted from the outputs of a first autocorrelator with a first time-lag and a second autocorrelator with a second time-lag. The extracted first and second phases are combined to generate an estimated CFO of high accuracy and wide estimation range.

A 5th generation (5G) or pre-5G communication system for supporting a data transmission rate higher than that of a 4th generation (4G) communication system, such as long term evolution (LTE) is provided. The wireless communication system, includes a plurality of antennas for identifying a plurality of radio signal, a receiver for receiving the plurality of the radio signals via the plurality of the antennas, wherein the receiver may include a coupler circuit for coupling the plurality of the received signals to different signal paths, to generate a first coupling signal by summing the plurality of the received signals and a second coupling signal corresponding to a difference of the plurality of the received signals, and a beam generator for generating a plurality of beamformed signals based on in-phase signals and quadrature-phase signals corresponding to the first coupling signal and the second coupling signal.

A precoding method, a precoding apparatus, a Frequency Domain Equalization (FDE) method, and an FDE apparatus are provided in the embodiments of the present invention. The precoding method includes: performing offset modulation for a transmitting signal vector; calculating a precoding matrix according to the offset-modulated transmitting signal vector and a receiver decision signal vector, where the precoding matrix is used for performing precoding for the transmitting signal vector; and performing precoding for the transmitting signal vector according to the precoding matrix. Linear precoding is performed by using the offset-modulated signal on the transmitter, and therefore, the interference caused by multiple antennas and multipath propagation is reduced, the system BER is reduced, and the complexity of implementation is low.

A direct sequence spread spectrum (DSSS) receiver includes an antenna, signal-to-noise ratio (SNR) estimation logic, and preamble detection logic. The antenna is configured to receive a DSSS signal. The SNR estimation logic is configured to estimate SNR of the received DSSS signal. The preamble detection logic is configured to, in response to the SNR estimate exceeding a SNR threshold value, detect a preamble sequence in the DSSS signal based on an absolute value of a sequence of correlation values. The sequence of correlation values is a complex quantity.

A method and system for cross-technology communication from a WiFi device to a ZigBee device includes: generating, by a WiFi transmitter, to-be-transmitted symbol-level energy modulation bits information simultaneously carrying WiFi data bits and cross-technology data bits transmitted to the ZigBee device, wherein the cross-technology data bits are obtained based on symbol-level energy modulation; and a ZigBee receiver processing received signal strength indication sample information and initiating a cross-technology communication receiving process to obtain the cross-technology data bits needing to be received, and meanwhile a WiFi receiver obtaining the to-be-transmitted symbol-level energy modulation bits information through a standard WiFi receiving process, and then initiating a WiFi data recovery process to obtain original WiFi data bits.