A method of searching for the presence of a useful signal of predefined spectral width ΔB in a multiplexing band having a spectral width greater than ΔB, includes calculating a frequency signal representative of a power spectral density in the multiplexing band, calculating a non-useful signal by filtering the frequency signal by means of a filter capable of suppressing all or part of signals having a spectral width equal to or smaller than ΔB, calculating a power ratio signal representative of the ratio of the frequency signal to the non-useful signal, and comparing the power ratio signal with a predefined threshold value. The method may be employed using a computer program product, a receiver unit, and/or a station of a digital telecommunications system comprising such a receiver unit.

Embodiments of the present disclosure disclose a signal transmission apparatus and method, and a wireless access node, and relate to the field of communications technologies, so as to resolve a problem that a spectrum cannot be fully used. The method of the present disclosure includes: obtaining, by a wireless access node, configuration information for use to transmit a signal of a second carrier in coverage space of a first carrier, a spectrum occupied by the first carrier and a spectrum occupied by the second carrier overlap, and a subcarrier of the first carrier and a subcarrier of the second carrier are orthogonal; and transmitting, by the wireless access node, the signal of the second carrier according to the configuration information. The present disclosure is applicable to a scenario in which a signal of a carrier is transmitted in coverage space of another carrier.

A communications node operable to communicate with another communications node over a communications channel having a plurality of frequency resources, the communications node includes data defining a division of the communications channel into a plurality of contiguous sub-bands each having N frequency resources, wherein each frequency resource in a sub-band has a corresponding frequency resource in each of the other sub-bands, data defining an initial allocation of the frequency resources, a resource determination module operable to apply a frequency shift to the initially allocated frequency resources in accordance with a frequency hopping sequence to determine frequency resources to use for communicating information with the other communications node, wherein the frequency shift applied moves the initially allocated frequency resources to corresponding frequency resources in another sub-band, a transceiver for communicating information with the other communications node using the determined frequency resource.

A satellite communications system is disclosed, the system comprising a ground controller, a decode-and-forward (DF) satellite transponder, and a digital high-power amplifier (HPA). The DF is further comprised of a transponder front end including a digital channelizer and a predistorter. The ground controller is configured to transmit multiple-access frequency-division-multiplexed signals to the DF, where the DF is configured to down-convert the signals received at the transponder front end. The digital channelizer is configured to convert the signals received into a single sample steam and feed the stream through the predistorter into the single digital HPA, wherein the HPA is configured to amplify each input sample of the stream in sample-by-sample fashion and generates a discrete output. The DF is further configured to convert the output of the digital HPA to a continuous time signal and up-convert the output with a main carrier frequency for down-link transmission to multiple-access ground users.

A satellite communications system is disclosed, the system comprising a ground controller, a decode-and-forward (DF) satellite transponder, and a digital high-power amplifier (HPA). The DF is further comprised of a transponder front end including a digital channelizer and a predistorter. The ground controller is configured to transmit multiple-access frequency-division-multiplexed signals to the DF, where the DF is configured to down-convert the signals received at the transponder front end. The digital channelizer is configured to convert the signals received into a single sample steam and feed the stream through the predistorter into the single digital HPA, wherein the HPA is configured to amplify each input sample of the stream in sample-by-sample fashion and generates a discrete output. The DF is further configured to convert the output of the digital HPA to a continuous time signal and up-convert the output with a main carrier frequency for down-link transmission to multiple-access ground users.

A communications node operable to communicate with another communications node over a communications channel having a plurality of frequency resources, the communications node includes data defining a division of the communications channel into a plurality of contiguous sub-bands each having N frequency resources, wherein each frequency resource in a sub-band has a corresponding frequency resource in each of the other sub-bands, data defining an initial allocation of the frequency resources, a resource determination module operable to apply a frequency shift to the initially allocated frequency resources in accordance with a frequency hopping sequence to determine frequency resources to use for communicating information with the other communications node, wherein the frequency shift applied moves the initially allocated frequency resources to corresponding frequency resources in another sub-band, a transceiver for communicating information with the other communications node using the determined frequency resource.

Devices, systems and methods for operating a rear-facing perception system for vehicles are described. An exemplary rear-facing perception system contains two corner units and a center unit, with each of the two corner units and the center unit including a camera module and a dual-band transceiver. A method for operating the rear-facing perception system includes pairing with a control unit by communicating, using the dual-band transceiver, over at least a first frequency band, transmitting a first trigger signal to the two corner units over a second frequency band non-overlapping with the first frequency band, and switching to an active mode. In an example, the first trigger signal causes the two corner units to switch to the active mode, which includes orienting the camera modules on the center unit and the two corner units to provide an unobstructed view of an area around a rear of the vehicle.

Systems, methods, apparatuses, and computer program products for signal multiplexing of data and radar transmissions. For instance, certain embodiments may provide a configurable time and frequency domain comb signal for radar excitation on a spatial beam and/or multiplexing data communications and radar signals in time, frequency, and/or spatial domains (e.g., beams).

The present invention relates to the field of communications, and more particularly to methods and a system for providing high-speed communications on a high-speed railway. The technical result is a better quality communication channel provided by train-to-ground radio relay links The claimed system for providing high-speed communications on a high-speed railway comprises an internal and an external data exchange network. The internal network unites tail-end radio frequency modules mounted in the rear part of a train and equipped with narrow-band antennae, head-end radio frequency modules mounted in the front part of the train and equipped with narrow-band antennae, and switching equipment capable of processing signals from said modules and of providing network devices connected to said equipment with access to the external data exchange network. The external data exchange network unites base stations equipped with narrow-band antennae, said base stations being capable of establishing communication with the tail-end and head-end radio frequency modules in the train and being arranged in proximity to the railway clearance along the path of travel of the train. The antennae of the base stations and of the radio frequency modules in the train are configured to radiate radio waves in a short millimeter wave band.

The present invention relates a method and apparatus for transmitting/receiving data using multiple codewords in a communication system using SC-FDMA (single carrier frequency division multiple access). A transmitter generates the multiple codewords for user data and transmits the generated multiple codewords. A receiver receives the multiple codewords and sequentially performs decoding and SIC (successive interference cancellation) on the received multiple codewords. Therefore, this structure can minimize a PAPR (peak to average power ratio) and considerably reduces interference between symbols in a frequency selective fading environment.