Methods, systems, and devices for wireless communications are described. In some systems, a user equipment (UE) may measure a frequency selectivity of a channel between the UE and a base station and may transmit signaling to the base station indicating one or both of a frequency selectivity metric or a recommended demodulation reference signal (DMRS) port multiplexing pattern based on measuring the frequency selectivity. In some aspects, the UE may transmit the signaling to assist the base station in configuring a DMRS port multiplexing pattern based on current channel conditions. For example, if the frequency selectivity metric satisfies a threshold, the UE may recommend a DMRS port multiplexing pattern absent of code division multiplexing (CDM). Alternatively, if the frequency selectivity metric fails to satisfy the threshold, the UE may recommend a DMRS port multiplexing patter including CDM.

The disclosed systems, structures, and methods are directed to a wireless receiver. The configurations presented herein employ a signal encoder configured to encode a plurality of received analog signals into a single encoded analog composite signal, in accordance with a variable leading bit orthogonal coding scheme, an analog-to-digital converter (ADC) configured to convert the single encoded analog composite signal into a single encoded digital composite signal containing constituent digital signals, a synchronization module configured to provide the variable leading bit orthogonal coding scheme to the signal encoder, and a signal decoder configured to decode the single encoded digital composite signal in accordance with the variable leading bit orthogonal coding scheme, to output a plurality of digital signals containing the desired information content of the received plurality of analog signals.

A receiver circuit for separating a plurality of layers multiplexed in an orthogonal frequency domain multiplexed (OFDM) signal includes: a descrambling sub-circuit configured to descramble a plurality of signals received on non-adjacent subcarriers of the OFDM signal to generate a plurality of descrambled signals; an inverse fast Fourier transform sub-circuit configured to transform the descrambled signals from a frequency domain to a received signal including a plurality of samples in a time domain; and a layer separation sub-circuit configured to separate the layers multiplexed in the received signal by: defining a first time domain sampling window and a second time domain sampling window in accordance with a size of the inverse fast Fourier transform; extracting one or more first layers from the samples in the first time domain sampling window; and extracting one or more second layers from the samples in the second time domain sampling window.

This disclosure provides systems, methods, and apparatuses, including computer programs encoded on computer storage media, for managing high volumes of space-time-streams in Wi-Fi systems. An access point (AP) may transmit packets including long training field (LTF) sections using a number of space-time-streams greater than eight. Mobile stations (STAs) in the system may or may not be capable of processing this number of streams. The AP may modulate an LTF section using a matrix with dimensions smaller than the number of streams by using tone-interleaving or by performing modulation with separate matrices in time and frequency. In some other implementations, the AP may split the antennas for transmission into groups, each group transmitting either different packets in a subset of streams or a same packet in a subset of tones. In further implementations, the AP may combine multiple space-time-streams into a super stream that supports reception at different types of STAs.

This application provides a reference signal indication method and apparatus. The method includes: transmitting, by a terminal device, a phase tracking reference signal (PTRS) to a network device based on a time domain density; and receiving, by the network device, the PTRS transmitted by the terminal device based on the time domain density, where the time domain density is a density in a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) waveform. Therefore, successful PTRS transmission can be ensured.

Methods and devices are disclosed for encoding and transmitting data sequences for low data rate applications. An encoded data sequence is transformed and used to shape a multi-carrier pulse to create a narrow-band signal for transmission. Time domain tails of the narrow-band signal may be removed to decrease overhead. The data may be first encoded to create a sparse modulated data sequence. Multi-carrier pulse shaping may be carried out using frequency division multiplexing (FDM) or filter bank multi-carrier (FBMC) techniques. Alternatively, single carrier pulse shaping may be used to create the narrow-band signal.

Examples described herein include devices and systems utilizing backscatter communication to generate transmissions in accordance with wireless communication protocols. Examples are described including single sideband operation, generation of a carrier wave using Bluetooth, downlink communication to a backscatter device, and combinations thereof.

A method for a base station processing an in-band emission interference signal caused when the base station operating in a Full Duplex Radio (FDR) mode transceives signals using a Frequency Division Multiplexing (FDM) manner includes transmitting a downlink signal in a flexible downlink duration of an uplink band; and processing the in-band emission interference signal caused by transmission of the downlink signal in an uplink duration of the uplink band, wherein the processing of the in-band emission interference signal is performed by puncturing a corresponding resource of the uplink duration, wherein the resource on the downlink signal is transmitted is mirrored to the corresponding resource of the uplink duration from a Direct Current (DC) subcarrier as a reference.

The present disclosure provides a transmitter and a corresponding method. The method includes: pre-processing a signal to be transmitter, the signals being across a plurality of sub-bands; filtering the signal to generate a universal-filtered orthogonal frequency division multiplexing (UF-OFDM) signal, where two or more sub-bands of the plurality of sub-bands are filtered by a common filter; and transmitting the generated UF-OFDM signal.

Accordingly, embodiments herein disclose a method for signal synchronization in orthogonal frequency-division multiplexing (OFDM) based Narrow Band-Internet of Thing (NB-IoT) system. The method includes generating a New Radio-Narrowband Primary Synchronization Signal (NR-NPSS). Further, the method includes mapping each Zadoff-chu sequence of 14 Zadoff-chu sequences of the NR-NPSS to resource elements of each OFDM symbol of 14 OFDM symbols in an NR-NPSS subframe. Further, the method includes transmitting the NR-NPSS subframe comprising the mapped NR-NPSS to at least one User Equipment (UE) (200), receiving the NR-NPSS subframe comprising the transmitted NR-NPSS by a base station (100), generating a reference NR-NPSS, mapping each of the 14 Zadoff-chu sequences of the NR-NPSS to resource elements of each OFDM symbol of 14 OFDM symbols in an NR-NPSS subframe, and detecting the NR-NPSS from the received NR-NPSS subframe using the reference NR-NPSS to obtain the time and frequency synchronization in the NB-IoT system.