Various embodiments disclosed herein enable steerable, time division duplex (“TDD”) communications channels at millimeter-wave frequency bands. Among other things, embodiments disclosed herein provide improved steering accuracy and power distribution, lower power consumption, and potentially longer service life than previous transceiver systems.

A transmission device includes a modulation unit that performs chirp-spread modulation on an input information series to generate a modulation signal; a delay unit that provides, to a plurality of modulation signals obtained by duplicating the modulation signal generated by the modulation unit, delays having lengths different from each other, a difference between the delays being an integral multiple of a reciprocal of a bandwidth of the modulation signal; and a plurality of transmission antennas that transmit the plurality of modulation signals, respectively, to which the delays are provided by the delay unit.

Transmitters, sensor systems, and methods of transmission include a frequency adjuster coupled to a ring oscillator to reduce latency and power consumption and to receive a signal from the ring oscillator. The frequency adjuster includes logic circuits to adjust the signal to a selected transmission frequency band. A band switch is coupled to the ring oscillator and the frequency adjuster to select logic circuits within the frequency adjuster to determine the selected transmission frequency band from a set of output frequency bands. A first radio front end is coupled to the frequency adjuster to transmit the signal on the selected transmission frequency band.

A mixer for mixing a radio frequency signal is described. The mixer includes a local oscillator input, a phase adjustment module, and at least one mixing channel. The local oscillator input is configured to receive a local oscillator signal. The phase adjustment module is configured to control a phase of the local oscillator signal in order to add a desired amount of delay to the local oscillator signal, thereby generating at least one adapted oscillator signal. The at least one adapted oscillator signal has a desired phase difference compared to the local oscillator signal. The at least one mixing channel includes at least one mixer unit having at least one signal input. The at least one mixing channel is configured to receive the at least one adapted oscillator signal. The at least one mixing channel further is configured to forward the adapted oscillator signal to the mixer unit. The at least one signal input is configured to receive an input signal. The at least one signal input further is configured to forward the input signal to the mixer unit. The mixer unit is configured to mix the at least one adapted oscillator signal with the input signal, thereby generating a mixer output signal.

An amplifier for a receiver circuit is disclosed. The amplifier has an input node (V.sub.in) and an output node (V.sub.out). It comprises a tunable tank circuit connected to the output node (V.sub.out), a feedback circuit path connected between the output node (V.sub.out) and the input node (V.sub.in), and a tunable capacitor connected between an internal node of the feedback circuit path and a reference-voltage node. A receiver circuit and a communication apparatus is disclosed as well.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a transceiver chain may receive, using a downconverter tuned by at least one local oscillator, transmit signals that are modulated using a modulation bandwidth and that span a total bandwidth greater than or equal to the modulation bandwidth. The at least one local oscillator may cover a first fraction of the total bandwidth. The transceiver chain may receive, using at least one analog-to-digital converter, input from the downconverter, and may output a first digital signal based at least in part on the input and sampling at the first fraction of the total bandwidth. The transceiver chain may determine an error associated with the transmit signals based at least in part on the first digital signal, and may perform digital pre-distortion on new signals based at least in part on the error. Numerous other aspects are described.

A radio frequency chip includes at least two signal generation circuits, at least three radio frequency transceiver circuits, and at least three intermediate frequency transceiver circuits. The at least two signal generation circuits include a first signal generation circuit and a second signal generation circuit. The first signal generation circuit and the second signal generation circuit are configured to generate radio frequency local oscillator signals in different frequency bands. Any radio frequency transceiver circuit receives only a radio frequency local oscillator signal from one signal generation circuit at a time. The radio frequency transceiver circuit is configured to perform conversion between a radio frequency signal and an intermediate frequency signal based on the received radio frequency local oscillator signal.

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 receiver includes a tunable receiving chain, configured to receive a subframe header when tuned to a first receiving bandwidth; a decoder, configured to decode an allocation information from the subframe header, the allocation information indicating an allocation of a plurality of resource blocks in the subframe; and a controller, configured to derive a second receiving bandwidth from the allocation information and to tune the receiving chain to the second receiving bandwidth.

Methods and systems for waking up a wireless receiving stations having wake-up radio (WUR) circuits. A method of providing a wake-up signal in a communications channel for a plurality of receiving stations, including generating at least a first series and a second series of waveform coded symbols, the first series being incorporated into a first wake-up-radio (WUR) frame that is intended for a first receiving station and has a first predefined bandwidth, the second series being incorporated into a second WUR frame that is intended for a second receiving station and has a second predefined bandwidth; combining the first and second WUR frames into a multiband WUR data unit having a bandwidth that is greater than a sum of the predefined bandwidths of the first and second WUR frames; and transmitting a wake-up signal including the multiband WUR data unit in the communications channel.