Patent classifications
H04L27/148
Method and apparatus for receiving FSK signals
Method of demodulation of M-CPFSK signal, includes receiving the M-CPFSK radio signal; moving it to zero frequency; sampling at no less than double a frequency of symbols; storing the samples with their amplitude and phase for at least L4 symbols; demodulating the sampled signal in three stages, wherein each stage includes iterating over symbol values within a block of symbols, of length is L1, L2 and then L3; in the first stage, N1 symbol sequences out of all possible symbol sequences are iterated over, at the second stage, N2 symbol sequences out of all possible symbol sequences are iterated over, and at the third stage, N3 symbol sequences out of all possible symbol sequences are iterated over, to obtain final symbol values; symbol values obtained at previous stage is used in a next stage to reduce a number of symbol sequences; and determining encoded bits based on final symbol values.
Transmit pre-coding
A user device communicates in a wireless network by encoding a set of data symbols with a set of complex-valued codes to produce a set of subcarrier values. The subcarrier values are modulated onto a set of Orthogonal Frequency Division Multiplexing (OFDM) subcarriers assigned to the user device to produce a time-domain waveform that comprises a superposition of modulated subcarriers, and the time-domain waveform is transmitted in the wireless network. The set of subcarrier values comprises a first polyphase code that encodes a first of the set of data symbols and at least a second polyphase code that encodes at least a second of the set of data symbols. The first polyphase code causes constructive and destructive interference between the modulated subcarriers to produce a first periodic pulse waveform having a peak value centered at a first time in an OFDM symbol interval, and the second polyphase code causes constructive and destructive interference between the modulated subcarriers to produce a second periodic pulse waveform having a peak value centered at a second time in the OFDM symbol interval, wherein the second time is different from the first time.
Transmit pre-coding
A user device communicates in a wireless network by encoding a set of data symbols with a set of complex-valued codes to produce a set of subcarrier values. The subcarrier values are modulated onto a set of Orthogonal Frequency Division Multiplexing (OFDM) subcarriers assigned to the user device to produce a time-domain waveform that comprises a superposition of modulated subcarriers, and the time-domain waveform is transmitted in the wireless network. The set of subcarrier values comprises a first polyphase code that encodes a first of the set of data symbols and at least a second polyphase code that encodes at least a second of the set of data symbols. The first polyphase code causes constructive and destructive interference between the modulated subcarriers to produce a first periodic pulse waveform having a peak value centered at a first time in an OFDM symbol interval, and the second polyphase code causes constructive and destructive interference between the modulated subcarriers to produce a second periodic pulse waveform having a peak value centered at a second time in the OFDM symbol interval, wherein the second time is different from the first time.
CIRCUIT AND METHOD FOR COMPENSATING FREQUENCY OFFSET IN WIRELESS FREQUENCY SHIFT KEYING COMMUNICATION
Disclosed are a circuit and method for compensating frequency offset in wireless frequency shift keying communication, and belongs to the field of wireless communication technologies. The circuit includes an analog-to-digital converter, a first decimating module, a digital down-converter, a second decimating module, a frequency offset estimator, a frequency shift keying demodulator, a timing recovery module, a synchronization header detector, a frequency recovery module, a numerical-control oscillator, and a differential decoding and symbol decision module. A rough frequency offset estimation value is combined with a slicer error to generate a control signal related to frequency offset in a received signal, and the control signal is transmitted to the numerical-control oscillator to adaptively adjust a center frequency of an oscillated signal.
CIRCUIT AND METHOD FOR COMPENSATING FREQUENCY OFFSET IN WIRELESS FREQUENCY SHIFT KEYING COMMUNICATION
Disclosed are a circuit and method for compensating frequency offset in wireless frequency shift keying communication, and belongs to the field of wireless communication technologies. The circuit includes an analog-to-digital converter, a first decimating module, a digital down-converter, a second decimating module, a frequency offset estimator, a frequency shift keying demodulator, a timing recovery module, a synchronization header detector, a frequency recovery module, a numerical-control oscillator, and a differential decoding and symbol decision module. A rough frequency offset estimation value is combined with a slicer error to generate a control signal related to frequency offset in a received signal, and the control signal is transmitted to the numerical-control oscillator to adaptively adjust a center frequency of an oscillated signal.
SYNCHRONOUSLY-SWITCHED MULTI-INPUT DEMODULATING COMPARATOR
Methods and systems are described for obtaining a set of carrier-modulated symbols of a carrier-modulated codeword, each carrier-modulated symbol received via a respective wire of a plurality of wires of a multi-wire bus, applying each carrier-modulated symbol of the set of carrier-modulated symbols to a corresponding transistor of a set of transistors, the set of transistors further connected to a pair of output nodes according to a sub-channel vector of a plurality of mutually orthogonal sub-channel vectors, recovering a demodulation signal from the carrier-modulated symbols, and generating a demodulated sub-channel data output as a differential voltage on the pair of output nodes based on a linear combination of the set of carrier-modulated symbols by controlling conductivity of the set of transistors according to the demodulation signal.
SYNCHRONOUSLY-SWITCHED MULTI-INPUT DEMODULATING COMPARATOR
Methods and systems are described for obtaining a set of carrier-modulated symbols of a carrier-modulated codeword, each carrier-modulated symbol received via a respective wire of a plurality of wires of a multi-wire bus, applying each carrier-modulated symbol of the set of carrier-modulated symbols to a corresponding transistor of a set of transistors, the set of transistors further connected to a pair of output nodes according to a sub-channel vector of a plurality of mutually orthogonal sub-channel vectors, recovering a demodulation signal from the carrier-modulated symbols, and generating a demodulated sub-channel data output as a differential voltage on the pair of output nodes based on a linear combination of the set of carrier-modulated symbols by controlling conductivity of the set of transistors according to the demodulation signal.
Cable modem and digital compensation for switchable analog filter to assist echo cancellation in full duplex cable modem
A cable modem supporting full duplex (FDX) operations. The cable modem includes a transmit circuitry configured to process a transmit signal and a receive circuitry configured to process a receive signal. The receive circuitry includes a switchable analog filter configured to filter the receive signal. The switchable analog filter is configurable for different passband frequencies. The receive circuitry also includes a digital compensation filter configured to compensate a difference in frequency response in a specific frequency band due to switching of the switchable analog filter for a different passband frequency. The cable modem also includes an adjacent channel interference (ACI) cancellation filter and an adjacent leakage interference (ALI) cancellation filter. A digital compensation filter is also used in processing the ACI cancellation signal and the ALI cancellation signal to impose or compensate the difference in frequency response due to the switchable analog filter switching.
Cable modem and digital compensation for switchable analog filter to assist echo cancellation in full duplex cable modem
A cable modem supporting full duplex (FDX) operations. The cable modem includes a transmit circuitry configured to process a transmit signal and a receive circuitry configured to process a receive signal. The receive circuitry includes a switchable analog filter configured to filter the receive signal. The switchable analog filter is configurable for different passband frequencies. The receive circuitry also includes a digital compensation filter configured to compensate a difference in frequency response in a specific frequency band due to switching of the switchable analog filter for a different passband frequency. The cable modem also includes an adjacent channel interference (ACI) cancellation filter and an adjacent leakage interference (ALI) cancellation filter. A digital compensation filter is also used in processing the ACI cancellation signal and the ALI cancellation signal to impose or compensate the difference in frequency response due to the switchable analog filter switching.
Methods, devices and systems for receiving and decoding a signal in the presence of noise using slices and warping
A method may comprise receiving and sampling a signal. The signal may encode a data packet. A slice may be generated and stored comprising a pair of values for each of a selected number of samples of the signal representing a correlation of the signal to reference functions in the receiver. The presence of the data packet may then be detected and the detected packet decoded from the stored slices. The generating and storing slices may be carried out as the received signal is sampled. The sampled values of the signal may be discarded as the slices are generated and stored. The slice representation of the signal can be manipulated to generate filters with flexible bandwidth and center frequency.