This application provides a signal transmission method and apparatus. The method includes: obtaining, by a transmitter side, a first signal with N points; performing signal separation on the first signal with N points, to obtain two groups of signals (for example, a second signal with N points and a third signal with N points); combining the two groups of signals obtained through separation, to obtain a to-be-sent signal with 3N/2 points; and sending the signal with 3N/2 points to a receiver side, to enable the receiver to restore the first signal with N points from the received signal with 3N/2 points.

A method of determining reserved tones for reduction of a peak to average power ratio (PAPR) includes: selecting carrier indices for the reserved tones and generating a kernel signal based on the selected carrier indices; calculating a comparison reference average value of the kernel signal, selecting one of the calculated comparison reference average value and a prestored comparison reference average value, and preliminarily determining carrier indices of the reserved tones based on the selection; re-arranging an order of the preliminarily determined carrier indices; calculating a comparison reference average value of a kernel signal generated, whenever each of the re-arranged carrier indices is changed to another carrier index, to generate a plurality of comparison reference average values, and finally determining carrier indices of the reserved tones which generates a kernel signal having the smallest comparison reference average value among the comparison reference average values as the indices of the reserved tones.

Half tone offset may be utilized to mitigate signal distortion caused by DC bias within OFDM-based systems. In addition a cyclic prefix may be utilized within an OFDM-based system to mitigate inter-symbol-interference. Presented herein are techniques and methods to efficiently apply a cyclic prefix to an OFDM symbol with a half tone offset.

Methods, systems, and devices for wireless communications are described. For example, a user equipment (UE) may transmit a random access preamble to a base station as part of a random access procedure between the UE and the base station. To generate the random access preamble, the UE may repeat each time domain sample of a base sequence on a per-sample basis to obtain a repeated sequence that includes multiple repetitions of each time domain sample of the base sequence, with repetitions of the same sample being consecutive within the repeated sequence. The UE may perform such sample-wise repetition before adding a cyclic prefix (CP) to the repeated sequence or after adding a base CP to the base sequence.

In one embodiment, a method includes sending SRS received from a plurality of UEs associated with the base station to a DU associated with the base station, receiving information regarding a subset of the plurality of UEs selected for downlink data transmissions for an RBG, multi-user data to be transmitted to UEs in the subset, and identities of selected beams among a plurality of pre-determined beams to be associated with the UEs in the subset from the DU, where each of the plurality of pre-determined beams corresponds to a DFT vector, computing a precoding matrix for the RBG based on IDFT vectors corresponding to the selected beams, preparing pre-coded multi-user data by applying the precoding matrix to the multi-user data, and transmitting the pre-coded multi-user data to the UEs in the subset for the RBG using MIMO technologies.

A base station may determine a root for a sequence to be included in a signal to a UE. The base station may generate a generalized Chu sequence based on the root and scramble the generalized Chu sequence using a pseudorandom sequence that is common to a plurality of base stations. The base station may transmit the scrambled generalized Chu sequence to indicate the beginning of a downlink transmission. The UE may receive this scrambled generalized Chu sequence and determine if a beginning of a downlink transmission from a serving base station based on the received generalized Chu sequence and an expected generalized Chu sequence.

This disclosure provides systems, devices, apparatus, and methods, including computer programs encoded on storage media, for UW-OFDM waveform techniques. A UE may receive, from a base station, an indication of one or more parameters for the UW-OFDM waveform. The UE may subsequently receive, from the base station, a downlink transmission having the UW-OFDM waveform based on the one or more parameters. A location of redundant subcarriers for the UW-OFDM waveform may be based on at least one of frequency resources allocated for the UE or a combination of the frequency resources allocated to multiple UEs.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive first configuration information indicating a first guard interval associated with sidelink communications. The UE may transmit, to a base station and another UE, a first sidelink communication using the first guard interval. The UE may transmit, to the base station and using a second guard interval having a second length that is different from a first length of the first guard interval, an uplink communication. Numerous other aspects are described.

An example method of mapping a plurality of modulation symbols of a plurality of physical layer pipes present in a frame to a resource grid of data cells for the frame is described. The modulation symbols of the plurality of physical layer pipes are represented by a two-dimensional array comprising the modulation symbol values for the plurality of physical layer pipes and the resource grid of data cells is represented by a one-dimensional sequentially indexed array.

This application provides example data transmission methods and apparatuses, so that a PAPR of time-domain sending data can be reduced. One example method includes a transmit end performing modulation data processing on first modulation data whose length is M.sub.1, to obtain second modulation data whose length is M.sub.2, where M.sub.1<M.sub.2, M.sub.1 and M.sub.2 are positive integers, and each modulation data in the second modulation data is an element in the first modulation data. The transmit end then performs sending preprocessing, such as phase shift, Fourier transform, inverse Fourier transform, or time/frequency domain filtering on the second modulation data to obtain time-domain sending data of one symbol. The transmit end then sends the time-domain sending data on the one symbol.