An in-phase and quadrature mismatch compensator for a quadrature transmitter includes a delay element, a complex-valued filter and an adder. The delay element receives an input transmit signal and outputs a delayed transmit signal. The complex-valued filter receives the input transmit signal and outputs a selected part of a filtered output transmit signal. The adder adds the delayed transmit signal and the selected part of the filtered output transmit signal and outputs a pre-compensated transmit signal. In one embodiment, the selected part of the filtered output transmit signal includes the real part of the complex-valued output transmit signal. In another embodiment, the selected part of the filtered output transmit signal includes the imaginary part of the complex-valued output transmit signal. Two transmit real-valued compensators are also disclosed that combine the in-phase and quadrature signals before being filtered.

In order to provide a receiver capable of accurately determining a phase difference of I/Q signals, a receiver includes a section detector configured to detect a section between a rising and a falling of a phase based on the rising and the falling of the phase represented by I/Q signals generated based on an advertisement packet transmitted from a transmitter, and a section setting unit configured to identify, within the section between the rising and the falling of the phase, a period in which a first variation amount of the phase is equal to or less than a first predetermined amount, and use the identified period as a section for detecting the phase of the I/Q signals. The section detector detects the rising when a first phase is smaller than a last phase among a plurality of phases acquired by sampling the phases.

Methods, systems, and devices for wireless communications are described that allow for a first user equipment (UE) to forward a transmission from a second UE to a base station. The forwarding techniques may include the first UE performing a decoding procedure on a message received from the second UE via a sidelink communications link. Based on the results of the decoding procedure, the first UE may select an amplify and forward (AF), decode and forward (DF), or a combination thereof to forward the message from the second UE to the base station. The base station may receive the forward messages and, in some cases, a message directly from the second UE, and may determine decoding weights to use to jointly decode the two messages received at the base station.

In 5G and 6G, a message received with even a single-bit fault generally discarded and a retransmission is requested. However, the faulted message contains a wealth of information that the receiver can use to avoid, or at least mitigate, such faults thereafter. Disclosed is a method for comparing a faulted message with an unfaulted copy, thereby determining which part of the message is faulted, and specifically how it was faulted. For example, the fault may have been an amplitude fault in which a demodulated amplitude differs by one level from the initially modulated amplitude, or it may be a phase fault in which the received phase differs by one phase level, or there may be a displacement by multiple amplitude or phase levels (a non-adjacent fault). Different mitigation strategies are disclosed for each situation, including AI models configured to select a suitable modulation scheme to combat specific faults.

A faulted 5G/6G message may be recovered by finding the faulted message elements and altering them until the fault is corrected. Disclosed are methods to evaluate the modulation quality of each message element using multiple criteria. The receiver can determine a first quality by measuring the overall (sum-signal) amplitude and phase of each message element, and comparing to the predetermined amplitude and phase levels. The receiver can determine a second quality by separating the overall wave into orthogonal components (branches) and comparing the branch amplitudes to the predetermined levels. The receiver can determine a third quality according to the SNR of the overall signal and the two branch signals. By combining the first, second, and third quality factors, the receiver can identify the most likely faulted message elements. The receiver can then alter the worst message elements in a nested grid search to find the correct message version.

Methods and devices are disclosed that derive an IQ magnitude parameter, and then determine the optimum IQ magnitude for wanted signals with negative signal to noise values. For each device installation, a calibration routine may be carried out that sets the baseband gain to produce this optimum IQ magnitude for each frequency channel.

A method and device in a UE and a base station used for wireless communications. The UE first receives a first signaling, and then transmits a first radio signal; the first signaling is used for determining K REs, and K first-type complex numbers are used for generating a baseband signal of the first radio signal through a baseband signal generation for generating an SC-FDMA baseband signal, a modulation scheme employed by the first radio signal is π/2-BPSK, K first-type parameters respectively correspond to the K first-type complex numbers, the K REs occupy contiguous subcarriers in frequency domain. The K first-type parameters are related to a center frequency of the contiguous subcarriers occupied by the K REs, each of the K first-type parameters is related to a length of cyclic prefix of an RE onto which a corresponding first-type complex number is mapped. The present disclosure improves uplink coverage performance.

A transmitter includes: a modulation circuit that modulates a data sequence using QAM by mapping the data sequence to only four symbols each of which differs in phase by 90 degrees from an adjacent one of the four symbols and at least two of which have different amplitudes; and a transmission circuit that wirelessly transmits the data sequence mapped to the four symbols through the modulation by the modulation circuit, by assigning the data sequence mapped to the four symbols through the modulation by the modulation circuit to different subcarriers for Orthogonal Frequency Division Multiplexing (OFDM).

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive pilot signaling associated with inphase and quadrature (IQ) mismatch estimation for a set of antennas of a base station. The UE may measure pilot signals for each of the set of antennas based on a pilot signal pattern of the pilot signaling, and calculate an estimation of an IQ mismatch for each antenna of the set of antennas of the base station based on measuring the pilot signals. The base station may receive, from the UE, a report including an indication of the estimation of the IQ mismatch for each antenna of the set of antennas of the base station based on the pilot signals.

Architectures for inter-converting bitstreams and symbol streams of PAM and/or QAM constellations of different sizes that are not base-2 integers. Some of such constellations may be Gray-coded, and the constellation mapping may be performed to achieve an equiprobable distribution of different constellation symbols. Some embodiments may be compatible with FEC schemes. In an example embodiment, a transmitter DSP may employ a conventional constellation mapper preceded by an electronic encoder programmed to exclude some constellation-symbol labels from the bitstream applied to the mapper. In different embodiments, the electronic encoder may employ a CCDM and/or a long-division operation to select some amplitudes of the constellation and to exclude others. At least some embodiments are beneficially capable of achieving a smaller gap to the Shannon limit than comparable conventional solutions.