The present disclosure may be embodied as a transmitter for multiuser multicarrier-chirp-division-multiplexing (“MU-MCDM”) communications. The present disclosure may be embodied as a receive for MU-MCDM communications. The present disclosure may also be embodied as a method for transmitting an MU-MCDM communication signal. The present disclosure may also be embodied as a method for receiving an MU-MCDM communication signal.

The present disclosure may be embodied as a transmitter for multiuser multicarrier-chirp-division-multiplexing (“MU-MCDM”) communications. The present disclosure may be embodied as a receive for MU-MCDM communications. The present disclosure may also be embodied as a method for transmitting an MU-MCDM communication signal. The present disclosure may also be embodied as a method for receiving an MU-MCDM communication signal.

A radio frequency (RF) transceiver includes a reference signal source to generate a reference signal, a local RF source to generate a local RF signal and a mixed-signal phase/frequency detector to compare the reference signal to the local RF signal, and to generate a difference signal from the comparison, wherein the difference signal comprises a modulation component and an error component. The transceiver also includes a receiver front end to receive and downconverts an angle-modulated RF signal to a baseband signal, a quadrature modulator configured to angle-modulate the reference signal source with the baseband signal.

A demodulation unit for recovering a transmitted symbol from a received signal that has been modulated using an MDPSK modulation scheme is described. The demodulation unit is configured to, for a current time instant, derive a current sample of a phase signal indicative of a phase of the received signal. Furthermore, the demodulation unit is configured to determine a set of discrimination signals for the current sample of the phase signal, based on the current sample of the phase signal and based on one or more previous samples of the phase signal for one or more previous time instants. In addition, the demodulation unit is configured to determine the transmitted symbol for the current time instant based on the set of discrimination signals.

A method and system of transmitting data. The method comprises receiving data, in a memory of the server computing device, from an asset tracker device; determining, in a processor of the server computing device, one or more weighting factors representing a respective priority associated with one or more of a latency, a cost, a power utilization and a throughput associated with transmission of the data for each of a plurality of communication channels; and selecting, from the plurality of communication channels, a communication channel for transmission of the data based at least in part on the one or more weighting factors and a transmission schedule for the data.

A radio frequency (RF) transceiver includes a reference signal source to generate a reference signal, a local RF source to generate a local RF signal and a mixed-signal phase/frequency detector to compare the reference signal to the local RF signal, and to generate a difference signal from the comparison, wherein the difference signal comprises a modulation component and an error component. The transceiver also includes a receiver front end to receive and downconvert an angle-modulated RF signal to a baseband signal, a quadrature modulator configured to angle-modulate the reference signal source with the baseband signal.

Clustering-based methods, apparatuses for frequency offset determination and elimination and electronic devices are disclosed. The clustering-based method for frequency offset determination includes: determining a constellation diagram for a received signal; determining N different values within a preset frequency interval, as N frequency offset estimates for a frequency offset of the received signal; for each of the frequency offset estimates, correcting the constellation diagram based on the frequency offset estimate to obtain a corrected constellation diagram, clustering signal points on the corrected constellation diagram, and calculating an area of a signal region in the corrected constellation diagram after clustering; and determining a frequency offset estimate corresponding to a signal region with a minimum area as a value of the frequency offset. The embodiments of the present invention can improve the accuracy and stability of the calculated value of the frequency offset.

A method and system of transmitting data. The method comprises receiving data, in a memory of the server computing device, from an asset tracker device; determining, in a processor of the server computing device, one or more weighting factors representing a respective priority associated with one or more of a latency, a cost, a power utilization and a throughput associated with transmission of the data for each of a plurality of communication channels; and selecting, from the plurality of communication channels, a communication channel for transmission of the data based at least in part on the one or more weighting factors and a transmission schedule for the data.

A demodulation system for demodulating an input signal is provided. The input signal includes a carrier wave modulated with data symbols selected from a plurality of candidate complex symbol values. The system includes a carrier recovery module, operative to compensate for a carrier frequency of the carrier wave and output a demodulated data signal. The carrier recovery module includes: a first complex-signal conversion module, operative to convert the input signal into a complex-valued input signal; a voltage-controlled oscillator; a mixer, for mixing the complex-valued input signal and a complex-valued output signal of the voltage-controlled oscillator, and generating a mixer output signal; a low-pass filter, coupled to the mixer, operative to filter the carrier frequency from the mixer output signal, and output a signal corresponding to the demodulated data signal; and a folding module, operative to apply a folding algorithm to the output signal of the low-pass filter.

A method and apparatus for decomposition of signals with varying envelope into offset components are disclosed here, that sample the time variant envelope of a single carrier (SC) or a multi-carrier (MC) band limited signal, quantizes the sampled value using N.sub.b quantization bits and decomposes the sample into N.sub.b in-phase and quadrature components that are combined in pairs and modulated to generate a set of N.sub.b offset signals. The pulse shape applied in each offset signal is selected according to the spectral mask needed for the signal and to minimize envelope fluctuations in each offset signal from the set of N.sub.b components.