The present specification relates to a reception apparatus and method for demodulating a signal in a wireless AV system. The reception apparatus estimates a transmission signal on the basis of an MMSE weight matrix. The reception apparatus divides the estimated transmission signal for respective reception antennas and performs an IFFT. The reception apparatus estimates and compensates for phase noise for the respective reception antennas on the basis of the signal for which the IFFT has been performed. The reception apparatus demodulates the estimated and compensated signal for respective streams.

A receiver for receiving data in a broadcast system includes a broadcast receiver configured to receive, via the broadcast system, a receiver input data stream including a plurality of channel symbols represented by constellation points in a constellation diagram. A demodulator demodulates the channel symbols into codewords and a decoder decodes the codewords into output data words. A redundancy unit selects or requests, if demodulation of a channel symbol and/or decoding of a codeword is erroneous or likely to fail, redundancy data for demodulation of future channel symbols and/or decoding of future codewords via a broadband system and a broadband receiver obtains the redundancy data via the broadband system. The demodulator and/or the decoder is configured to use the obtained redundancy data to demodulate the respective future channel symbols and to decode the respective future codewords, respectively.

In one aspect, an apparatus includes: a front end circuit to receive and process incoming radio frequency (RF) signals into orthogonal frequency division multiplexing (OFDM) samples; a fast Fourier transform (FFT) engine to receive and convert the OFDM samples into frequency domain sub-carriers; a demodulator to demodulate the frequency domain sub-carriers; a channel estimator to: compute a first pilot channel estimate for a first channel condition comprising a flat channel condition and a second pilot channel estimate for a second channel condition comprising a selective channel condition based on a first set of pilot sub-carriers of the frequency domain sub-carriers; and select one of the first and second pilot channel estimates using the first and second pilot channel estimate; and a control circuit to configure at least the demodulator based at least in part on the selected first or second pilot channel estimate.

When an OFDM radio system which uses a wide frequency band is interfered with by another narrow-band radio system, the interference can frequently be compensated but the transmission quality decreases drastically. Thus, narrow-band interferers in an OFDM radio system are determined according to the invention whereby none of the subscribers of the radio system transmits in a defined time slot or scan slot but all switch at the same time into the receiving mode. If there is interference (P1, P2), it is detected in this time slot. Countermeasures are taken individually in all the mobile devices, in particular the detection of the frequency and strength of the narrowband interference (P1, P2) and the configuration of a flexible notch filter (140) in the time range to the detected frequency and strength. The scanned received signal (RXS) is then filtered in the time range, i.e. before the FFT (120) and the OFDM channel estimation (130) by the correspondingly configured notch filter (140). The notch (S1, S2) of the notch filter thereby acts in the transmission function like a natural break when receiving data.

Methods, systems, and devices for wireless communications are described. A base station may transmit an indication of a demodulator configuration to a user equipment (UE) for the UE to use that demodulator configuration for demodulating a multi-layer transmission from the base station. The base station may determine the demodulator configuration for the UE to use based on one or more uplink signals transmitted from the UE. Additionally, the UE may transmit an indication of demodulator capabilities that the UE supports to the base station, where the base station determines the demodulator configuration based on the indication of the demodulator capabilities. In some examples, the demodulator configuration may indicate a demodulation search space corresponding to a number of layers included per layer group of the multi-layer transmission, may correspond to an amount of cross correlation determined between respective layers of the multi-layer transmission, or a combination thereof.

A signal demodulation method, a signal transmission method, and a related apparatus. The signal demodulation method includes: a terminal device receives a first tracking reference signal from a first transmission reception apparatus of a single frequency network cell; a second tracking reference signal occupying different time-frequency from the first tracking reference signal from a second transmission reception apparatus of the single frequency network cell; and receives indication information indicating tracking reference signals from the first transmission reception apparatus or the second transmission reception apparatus; determines, based on the one or more tracking reference signals for receiving the downlink signal, a first carrier frequency on which the downlink signal is to be received; receives the demodulation reference signal and the downlink data based on the first carrier frequency; and demodulates the downlink data based on the demodulation signal.

The disclosure deals with system and method for an over-the-air computation (AirComp) scheme for federated edge learning (FEEL) without channel state information (CSI) at the edge devices (EDs) or edge server (ES). The disclosure adopts the majority vote (MV) principle and defines multiple subcarriers and orthogonal frequency division multiplexing (OFDM) symbols for voting options, which reduces to frequency-shift keying (FSK) over OFDM subcarriers as a special case. Thus, FSK-based over-the-air computation is provided for federated edge learning without channel state information. Since the votes from EDs are separated on orthogonal resources, the proposed scheme eliminates the need for truncated-channel inversion (TCI) at the EDs and allows the ES to detect MV with a non-coherent detector. We also mitigate the peak-to-mean envelope power ratio (PMEPR) of the synthesized signals by using randomization symbols. Simulations show the proposed scheme provides high test accuracy in fading channels for both independent and identically distributed (IID) and non-IID data while resulting in OFDM symbols with lower PMEPRs as compared to one-bit broadband digital aggregation (OBDA) with quadrature amplitude modulation (QAM).

In one embodiment, an apparatus comprises: a baseband processor having a preamble generation circuit to generate a preamble for an orthogonal frequency division multiplexing (OFDM) transmission, the preamble generation circuit to generate the preamble having a first portion comprising a first plurality of symbols and a second portion comprising a second plurality of symbols, where the preamble generation circuit is to generate at least some of the second plurality of symbols having at least one frequency disruption between successive symbols of the second portion; a digital-to-analog converter (DAC) coupled to the baseband processor to convert the first plurality of symbols and the second plurality of symbols to analog signals; a mixer coupled to the DAC to upconvert the analog signals to radio frequency (RF) signals; and a power amplifier coupled to the mixer to amplify the RF signals.

Techniques are disclosed relating to generating and receiving radio frames with multiple portions that have different target geographic areas. A data frame may include a first partition that includes a physical layer encoding of first data to be transmitted in a first geographic area, where the first geographic area is defined by a first threshold distance from the one or more transmitters. The data frame may include a second that includes a physical layer encoding of second data to be transmitted in a second geographic area, where the second geographic area is defined by a second, greater threshold distance from the one or more transmitters.

The present invention provides an apparatus of transmitting broadcast signals. The apparatus includes, an encoder for encoding service data, a bit interleaver for bit interleaving the encoded service data, a mapper for mapping the bit interleaved service data into a plurality of OFDM (Orthogonal Frequency Division Multiplex) symbols to build at least one signal frame, an OFDM modulator for modulating data in the built at least one signal frame by an OFDM scheme and a transmitter for transmitting the broadcast signals having the modulated data.