A method implemented by a wireless fronthaul unit, the method comprises aggregating a plurality of first wireless channel signals to produce a first aggregated signal via digital frequency-domain mapping (FDM), wherein the first wireless channel signals are positioned in the first aggregated signal in non-overlapping first frequency bands, each non-overlapping first frequency band having a first bandwidth and a center frequency, wherein each respective center frequency is an odd integer multiple of a lowest center frequency, converting the first aggregated signal into a first modulated signal, and transmitting the first modulated signal to a wireless fronthaul link.

Methods, systems, and devices for wireless communications are described for optimizing index modulated (IM) communications between a user equipment (UE) and a base station. The UE may identify a quantity of subcarriers for IM communications and transmit a message including an indication of the quantity of subcarriers to the base station. In some examples, the UE may transmit an indication of one or more subcarriers to exclude from IM communications. The base station may receive the indication of the quantity of subcarriers and/or the indication of the blacklisted subcarrier(s) and may determine a number of active subcarriers to be used based on at least the indication of the quantity of subcarriers. The base station may transmit an indication of the number of active subcarriers to the UE. The UE may process one or more received IM downlink signals based on the quantity of subcarriers.

Examples relating to techniques for wireless communications, e.g., visible light communication, VLC, are disclosed. In particular, there is disclosed a communication device for communicating with a plurality of other devices, using a wireless link. The device provides individual reference signals using a number of subcarriers or time slots in accordance to the optical clock reference and the number of transmitting devices in the set or streams to be transmitted in parallel. The device defines the position of subcarriers or of signals at the time slots in accordance to an identification number associated to an individual device within the whole set of transmitting devices or in dependence on an identification number identifying a specific stream or transmitter. The device transmits the reference signal which enables the plurality of receiving devices to identify the signal coming from the individual communication device in the whole set of devices.

A method and structure for equalization in coherent optical receivers. Block-based LMS (BLMS) algorithm is one of the many efficient adaptive equalization algorithms used to (i) increase convergence speed and (ii) reduce implementation complexity. Since the computation of the equalizer output and the gradient of the error are obtained using a linear convolution, BLMS can be efficiently implemented in the frequency domain with the constrained frequency-domain BLMS (FBLMS) adaptive algorithm. The present invention introduces a novel reduced complexity constrained FBLMS algorithm. This new approach replaces the two discrete Fourier transform (DFT) stages required to evaluate the DFT of the gradient error, by a simple frequency domain filtering. Implementation complexity can be drastically reduced in comparison to the standard constrained FBLMS. Furthermore, the new approach achieves better performance than that obtained with the unconstrained FBLMS in ultra-high speed coherent optical receivers.

A method for transmitting data through a multi-media communication network includes converting transmission entities into data symbols at a first communication device, transmitting the data symbols from the first communication device to a second communication device through at least two different types of communication media using only lower PHY layers of the at least two different types of communication media, and converting the data symbols into transmission entities at the second communication device. A network implementing a universal data link includes a first communication device configured to convert transmission entities into data symbols, a second communication device configured to convert the data symbols into transmission entities, at least a first communication medium and a second communication medium communicatively coupled between the first communication device and the second communication device, and a first physical-layer translator configured to translate data symbols without converting the data symbols into transmission entities.

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 method and structure for a coherent optical receiver device. Timing recovery (TR) is implemented after channel dispersion (i.e., chromatic dispersion (CD) and polarization mode dispersion (PMD)) compensation blocks. This architecture provides both improves performance and reduces power consumption of the device. Also, a TR loop is provided, enabling computing, by an error evaluation module, a first sampling phase error (SPE) and computing, by a timing phase information (TPI) module coupled to the error evaluation module, a second SPE from a plurality of CD equalizer taps PMD equalizer taps. The first and second SPE are combined into a total phase error (TPE) in a combining module, and the resulting TPE is filtered by a timing recovery (TR) filter coupled to an interpolated timing recovery (ITR) module and the combining module. The ITR module then synchronizes an input signal of the coherent optical receiver according to the TPE.

A communications system has a transmitter circuit for transmitting a communications signal. The transmitter receives a plurality of input data streams and applies an orthogonal function to each of the plurality of input data streams. The transmitter groups the input streams having the orthogonal function applied thereto into a plurality of groups. The orthogonal functions applied to the plurality of input data streams do not repeat within the plurality of groups to limit interference between the input data streams within the group. The transmitter applies a different wavelength to each of the plurality of groups input data streams. The different wavelengths limit interference between the plurality of groups of input data streams. The transmitter applies a positive polarization and a negative polarization to each of the plurality of groups of input data having a different wavelength applied thereto. The positive and the negative polarizations are applied to a pair of groups having a same wavelength applied thereto limit interference between the pair of groups. The transmitter transmits the plurality of input of data streams over a plurality of channels on a communications link as the communications signal. Each of the plurality of channels has a unique combination of orthogonal function, wavelength and polarization associated therewith.

Wireless communication techniques for transmitting and receiving reference signals is described. The reference signals may include pilot signals that are transmitted using transmission resources that are separate from data transmission resources. Pilot signals are continuously transmitted from a base station to user equipment being served. Pilot signals are generated from delay-Doppler domain signals that are processed to obtain time-frequency signals that occupy a two-dimensional lattice in the time frequency domain that is non-overlapping with a lattice corresponding to data signal transmissions.

Methods, systems, and devices for wireless communications are described. Generally, a transmitting device may send transmissions using a first numerology for a first type of user equipment (UE). The transmitting device may partition a stream of modulated data symbol tones into one or more contiguous subsets of modulated data symbol tones that result in a roughly frequency-flat channel for a second type of UE. The transmitting device may then perform precoding on individual subsets of the one or more contiguous subsets of modulated data symbol tones, and may insert a frequency-domain cyclic prefix, cyclic postfix, or guard interval after each precoded subset. Thus, the first type of UE may communicate using the first numerology and the second type of UE may communicate using the first numerology but with the frequency-domain cyclic prefixes to address doppler spread experienced by the second type of UE.