The disclosure describes design of a synchronization signal (SS) block for an unlicensed carrier, and listen before talk (LBT) strategies for initial access. An apparatus of a radio access network (RAN) is disclosed. The apparatus includes baseband circuitry that includes one or more processors and a radio frequency (RF) interface. The one or more processors are to generate, for user equipment (UE) operating on a licensed assisted access (LAA) secondary cell (SCell), a data sequence associated with an SS block. The SS block includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), but does not include a physical broadcast channel (PBCH). The RF interface is to receive the data sequence from the one or more processors.

Device, methods and systems for precoding in wireless systems using orthogonal time frequency space multiplexing are described. An exemplary method for transmitting wireless signals includes mapping data to generate a quadrature amplitude modulation (QAM) signal in a delay Doppler domain, determining a perturbation signal to minimize expected interference and noise, perturbing the QAM signal with the perturbation signal, thereby producing a perturbed signal, generating a pre-coded signal by pre-coding, using a linear pre-coder, the perturbed signal, and transmitting the pre-coded signal using an orthogonal time frequency space modulation signal scheme.

The present disclosure provides techniques for bandwidth constrained communication systems with frequency domain information processing. A bandwidth constrained equalized transport (BCET) communication system can include a transmitter, a communication channel, and a receiver. The transmitter can include a pulse-shaping filter that intentionally introduces memory into a signal in the form of inter-symbol interference, an error control code (ECC) encoder, a multidimensional fast Fourier transform (FFT) processing block and a multidimensional inverse FFT processing block that process the signal in the frequency domain, and a first interleaver. The receiver can include an information-retrieving equalizer, a deinterleaver with an ECC decoder, and a second interleaver joined in an iterative ECC decoding loop. The communication system can be bandwidth constrained, and the signal can comprise an information rate that is higher than that of a communication system without intentional introduction of the memory at the transmitter.

Aspects of the subject disclosure may include, for example, generating multiple digital reference pulses synchronously to a master oscillator, selectively switching the multiple digital reference pulses, and providing the switched pulses to multiple radio modules operating within a millimeter wave spectrum. For each radio module, counting cycles of an adjustable LO output signal occurring between consecutive pulses of the switched digital reference pulses, determining a difference between the count value and a reference value, and adjusting the adjustable LO according to the difference. A resulting corrected LO signal is synchronized to the master oscillator. Other embodiments are disclosed.

A method and an apparatus for implementing transmission diversity using a single transmitter in a wireless communication system are provided. The method of operating a transmitter for transmission diversity in a wireless communication system includes generating a first data symbol by receiving a baseband signal from a data source, generating a second data symbol having an equal phase to the first data symbol, generating a first complex conjugate symbol by performing a complex conjugate operation for the first data symbol, generating a second complex conjugate symbol having a phase difference of 180 degrees from the first complex conjugate symbol, transmitting the first data symbol through a first transmission antenna and transmitting the second data symbol through a second transmission antenna in a first time slot, and transmitting the first complex conjugate symbol through the first transmission antenna and transmitting the second complex conjugate symbol through the second transmission antenna in a second time slot.

Disclosed is an apparatus and a method of deriving an optimal precoder, in which a precoder is derived using water filling power allocation, and then is multiplied with some unitary matrix satisfying certain conditions to meet a per layer power constraint. Since the multiplication with the unitary matrix does not change the capacity, the derived precoder is optimal in achieving maximum capacity in a multiple input multiple output (MIMO) wireless communication scheme.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit an uplink payload in a wireless communications system. The UE may identify a set of sequences configured for conveying a payload including a set of bits, where each sequence of the set of sequences is orthogonal to each other sequence of the set of sequences. The UE may select a first sequence from the set of sequences based on a mapping between the set of sequences and payload values corresponding to the set of bits. The UE may transmit the payload including the set of bits using the first sequence.

A radio frequency module includes: a switch circuit including a transmit terminal, a receive terminal, a selection terminal, and a common terminal, the switch circuit being capable of switching between (A) a connection between the transmit terminal and the common terminal, (B) connections between the transmit terminal and the common terminal and between the selection terminal and the common terminal, (C) connections between the receive terminal and the common terminal and between the selection terminal and the common terminal, and (D) a connection between the receive terminal and the common terminal; a transmit/receive filter connected to the common terminal and to be used for a time division duplex system, a pass band of the transmit/receive filter being a transmit/receive band of Communication Band A; and a DTC connected to the selection terminal, the DTC changing its capacitance value according to connection switching of the switch circuit.

Embodiments of the invention include a wakeup receiver (WRX) featuring a charge-domain analog front end (AFE) with parallel radio frequency (RF) rectifier, charge-transfer summation amplifier (CTSA), and successive approximation analog-to-digital converter (SAR ADC) stages. The WRX operates at very low power and exhibits above-average sensitivity, random pulsed interferer rejections, and yield over process.

A method for modulating data for transmission within a communication system. The method includes establishing a time-frequency shifting matrix of dimension N×N, wherein N is greater than one. The method further includes combining the time-frequency shifting matrix with a data frame to provide an intermediate data frame. A transformed data matrix is provided by permuting elements of the intermediate data frame. A modulated signal is generated in accordance with elements of the transformed data matrix.