To provide improved phase noise tolerance and improved identification of certain fault types, a modulation/demodulation procedure is disclosed for 5G and 6G. The transmitter can modulate a message according to the amplitude and phase of the overall waveform to be emitted, modulated according to predetermined amplitude and phase levels of the modulation scheme. The receiver can then separate the received waveform into orthogonal I and Q branches and measure their branch amplitudes, as usual. The receiver can then convert the branch amplitude measurements back into the original amplitude-phase modulation parameters using formulas provided. The receiver can then demodulate the message by comparing the overall amplitude and phase of each message element to the predetermined amplitude and phase levels of the modulation scheme, which thereby provides substantially increased phase noise tolerance at high frequencies. The procedure can also diagnose fault types and identify faulted message elements specifically, among other benefits.

Example operations may include determining a first noise estimate of noise that propagates along a receive path of a device. The operations may further include determining a second noise estimate of the noise and determining a cross-relationship estimate with respect to the noise. In addition, the operations may include adjusting one or more correction filters configured to correct for imbalances between a first branch and a second branch of the receive path. The adjusting may be based on the first noise estimate, the second noise estimate, and the cross-relationship estimate.

Methods and apparatus for providing a demapping system with phase compensation to demap uplink transmissions. In an embodiment, a method is provided that includes detecting a processing type associated with a received uplink transmission, and when the detected processing type is a first processing type then performing the following operations: removing resource elements containing reference signals from the uplink transmission; layer demapping remaining resource elements of the uplink transmission into two or more layers; phase compensating all layers to generate phase compensated layers; and soft-demapping all phase compensated layers to produce phase compensated soft-demapped bits.

Precision synchronization is key to reliable communications at the high frequencies planned for 5G and 6G. A timing reference signal can provide a compact, resource-efficient, low-complexity phase noise mitigation while also providing an amplitude noise calibration. The timing reference signal is a QAM (quadrature amplitude modulation) signal with an I branch multiplexed with an orthogonal Q branch, in which one of the branches is modulated according to a maximum amplitude level of the modulation scheme, and the other branch has zero amplitude as-transmitted. When received, the amplitude and phase may be altered by noise. The receiver can measure the overall magnitude of the received I and Q signals to mitigate amplitude noise, and can also calculate a phase rotation angle according to a ratio of the I and Q branch signals as-received, and thereby correct for phase noise in the message.

A return channel system for ultra-small aperture terminals has a spreader that receives an input signal and outputs a spread spectrum signal having multiple replicated signals with a lower power than the input signal. A de-spreader includes a de-multiplexer that receives the spread spectrum signal via satellite. The de-multiplexer separates the spread spectrum signal into a first channel having a first signal and a second channel having a second signal. The de-spreader also has an offset compensation circuit having a phase estimator configured to estimate a phase offset between a phase of the first signal and a phase of the second signal. And a phase adjustor that receives the second signal and adjusts the phase of the second signal to align with the phase of the first signal to provide a phase-adjusted second signal. A summer combines the first signal with the phase-adjusted second signal to provide a composite signal.

A method, an apparatus and a computer program product for enhancing reception of signals in a wireless communication system. A signal containing a frame including a plurality of symbols is received on an uplink communication channel. An angular position of at least one symbol in the plurality of symbols in a constellation of symbols is detected. The plurality of symbols include equalized symbols. An angular difference corresponding a phase error between the detected angular position of the symbol and an expected reference angular position in the constellation of symbols corresponding to an expected reference symbol corresponding to the received frame is determined. Using the determined phase error, a phase of the symbol is compensated.

An electronic device includes a feedback oscillator configured to output a first oscillation signal and a second oscillation signal, the second oscillation signal having a defined phase difference from the first oscillation signal, the feedback oscillator including a phase shifter configured to receive the first oscillation signal and output the second oscillation signal, an up-conversion mixer configured to output a first loopback signal obtained by mixing the first oscillation signal with a reference tone signal, and output a second loopback signal obtained by mixing the second oscillation signal with the reference tone signal, and a receiver configured to generate a first reference IQ signal from the first loopback signal, generate a second reference IQ signal from the second loopback signal, and compare an actual phase difference between the first reference IQ signal and the second reference IQ signal with the defined phase difference.

A UE determines a respective set of subcarriers from N subcarriers in each OFDM symbol of M1 consecutive OFDM symbols within a slot. The respective set of subcarriers carries a respective set of SRSs that form transmission combs of a transmission comb size. The respective set of subcarriers in one of the M1 consecutive OFDM symbols do not overlap in frequency domain with the respective set of subcarriers in any other one of the M1 consecutive OFDM symbols. The UE applies the respective set of phase rotations to the respective set of SRSs in each OFDM symbol to obtain a cyclic shift. The UE maps the respective set of SRSs applied with phase rotations to the respective set of subcarriers in each OFDM symbol. The UE transmits the respective sets of SRSs in the M OFDM symbols.

Methods, systems, and devices for wireless communications are described. A phase rotation adjustment may be applied in cases where a transmitted signal is heterodyned. For instance, a device (e.g., a base station, a user equipment (UE), a wireless repeater) may determine that a receiving device may receive a transmitted signal at a carrier frequency that is different from a carrier frequency used by a transmitting device (e.g., such as in the case of a wireless repeater relaying the signal from the transmitting device to the receiving device). A phase rotation adjustment may be applied by the device (e.g., the base station, UE, or wireless repeater) to account for the heterodyning. The phase rotation adjustment may be based on the carrier frequency used by the receiving device to receive the signal. In some cases, a receiving device may also apply the phase rotation adjustment following the demodulation of a received signal.

A digital signal processor (DSP) for a receiver and a method for processing signals in a receiver are provided. The DSP comprises a processor configured to: receive a digital signal at a symbol rate in a frequency domain; and compensate an impairment of the digital signal in the frequency domain.