A method and an apparatus determine a precoding matrix indicator, user equipment, and a base station. The method includes: determining a precoding matrix indicator PMI, where the PMI corresponds to a precoding matrix W, and the precoding matrix W satisfies a first condition, a second condition, or a third condition; and sending the PMI to a base station. Embodiments of the present invention further provide a corresponding apparatus, and the corresponding user equipment and base station. Technical solutions provided in the embodiments of the present invention can effectively control a beam, especially a beam shape and a beam orientation, in a horizontal direction and a perpendicular direction.

A spreading sequence generator for a first radio frequency (RF) transceiver receives an RF signal from a second RF transceiver. The first RF transceiver measures power levels of the received RF signal at a plurality of instants to generate respective digital power level values and uses the plurality of digital power level values to create a first spreading sequence. The second RF transceiver receives an RF signal from the first RF transceiver and performs the same functions to create a second spreading sequence. Due to the reciprocal nature of the RF channel between the first and second RF transceivers, the first and second cryptographic keys match.

A method for generating a spreading sequence is disclosed. The method includes receiving a plurality of signals from a remote device. The plurality of signals is sampled to generate a plurality of data sets corresponding to the plurality of signals, respectively. Each data set indicates a power value of the corresponding signal. From the plurality of data sets, one or more data sets indicating a power value greater than a predetermined value is selected. A spreading sequence is generated based on the one or more selected data sets.

An approach is described for a method for a base station in a fifth generation (5G) wireless c01mnunication or a new radio (NR) system that includes the following steps. The method includes determining base initial seeds and a time parameter. The method further includes generating actual initial seeds based on the base initial seeds and the time parameter; generating a Pseudo-Noise (PN) sequence based on one of the actual initial seeds; and generating a remote interference management reference signal (RIM-RS) sequence based on the PN sequence. The method further includes transmitting the RIM-RS sequence to a remote base station.

An extensible communication system is described herein. The system includes a first module for receiving a root index value and for generating a constant amplitude zero auto-correlation sequence based on the root value. The system further includes a second module for receiving a seed value and for generating a Pseudo-Noise sequence based on the seed value. The system further includes a third module for modulating the constant amplitude zero auto-correlation sequence by the Pseudo-Noise sequence and for generating a complex sequence. The system further includes a fourth module for translating the complex sequence to a time domain sequence, wherein the fourth module applies a cyclic shift to the time domain sequence to obtain a shifted time domain sequence.

A method for generating spread spectrum spreading sequences in communicating devices. A first device receives a first sequence of one or more signals from a second device, sends a second sequence of one or more signals to the second device, samples the first sequence of one or more signals, generates sampling results, and generates a spreading sequence based on the sampling results. The second device receives the second sequence and creates an identical spreading sequence using an identical process to create sampling results and generate the sequence. The spreading sequence may be used by the first and second devices for spread spectrum communications with each other. Gain for spread spectrum communications may be dynamically varied based on available bandwidth by varying the number of signals and sampling rate.

A method in a wireless device is disclosed. The method comprises receiving a synchronization signal from a network node, the received synchronization signal comprising a synchronization sequence, a cell ID sequence, and a frame index indication sequence. The method further comprises estimating a time offset of the received synchronization signal using the synchronization sequence, and estimating a frequency offset of the received synchronization signal using the synchronization sequence. The method further comprises detecting a cell ID of a cell associated with the network node using the estimated time offset and the estimated frequency offset, and detecting a frame number using the estimated time offset, the estimated frequency offset, and the detected cell ID of the cell associated with the network node.

Embodiments herein achieve a method and system for selecting non-coherent spreading sequences with binary alphabets {0, 1} with variable spreading factors. The method generates circular shift equivalent sets of spreading sequences by circularly shifting base sequences with elements {1, 0} and having at least one variable spreading factor. The method determines whether each spreading sequence in the circular shift equivalent set meets pre-defined spreading sequence criteria. The spreading sequence criteria comprise balanced criteria, a non- repetition criteria, non-circular criteria, and conjugate criteria. Furthermore, the method selects the spreading sequence from expansions of at least one spreading sequence from the circular shift equivalent sets in response to determining that the spreading sequences in the circular shift equivalent sets meets the pre-defined spreading sequence criteria.

Fully connected uplink and downlink fully connected relay network systems using pseudo-noise spreading and despreading sequences subjected to maximizing the signal-to-interference-plus-noise ratio. The relay network systems comprise one or more transmitting units, relays, and receiving units connected via a communication network. The transmitting units, relays, and receiving units each may include a computer for performing the methods and steps described herein and transceivers for transmitting and/or receiving signals. The computer encodes and/or decodes communication signals via optimum adaptive PN sequences found by employing Cholesky decompositions and singular value decompositions (SVD). The PN sequences employ channel state information (CSI) to more effectively and more securely computing the optimal sequences.

A coded imaging and multi-user communications systems using novel codes, algorithms to develop such codes, and technological implementations to use the codes for various types of systems involving multiple (or single) transmitters and multiple (or single) receivers of signals (which could include but are not limited to electromagnetic radiation, acoustic waves, other types of waves or data) as a function of time-or-space.