Systems and methods for classifying a modulation scheme of a wireless signal are described. In some embodiments, a system receives a wireless signal modulated based on a modulation scheme having a constant modulus. The system can generate a resampled signal from the wireless signal based on features extracted from the wireless signal and perform blind equalization on the resampled signal based on a constant modulus criterion to generate an equalized signal. Then, the system can cause a modulation classifier to classify the received wireless signal to a modulation scheme from a plurality of predetermined modulation schemes based on the equalized signal. By preconditioning the wireless signal to reduce feature variability imparted by a propagation channel onto the wireless signal, the system can increase the classification accuracy of the modulation classifier.

Systems and methods for classifying a modulation scheme of a wireless signal are described. In some embodiments, a system receives a wireless signal modulated based on a modulation scheme having a constant modulus. The system can generate a resampled signal from the wireless signal based on features extracted from the wireless signal and perform blind equalization on the resampled signal based on a constant modulus criterion to generate an equalized signal. Then, the system can cause a modulation classifier to classify the received wireless signal to a modulation scheme from a plurality of predetermined modulation schemes based on the equalized signal. By preconditioning the wireless signal to reduce feature variability imparted by a propagation channel onto the wireless signal, the system can increase the classification accuracy of the modulation classifier.

Systems and methods for classifying a modulation scheme of a wireless signal are described. In some embodiments, a system receives a wireless signal modulated based on a modulation scheme having a constant modulus. The system can generate a resampled signal from the wireless signal based on features extracted from the wireless signal and perform blind equalization on the resampled signal based on a constant modulus criterion to generate an equalized signal. Then, the system can cause a modulation classifier to classify the received wireless signal to a modulation scheme from a plurality of predetermined modulation schemes based on the equalized signal. By preconditioning the wireless signal to reduce feature variability imparted by a propagation channel onto the wireless signal, the system can increase the classification accuracy of the modulation classifier.

A transmitter in a first wireless communication device and method therein are disclosed. The transmitter comprises a modulator and a rate selector configured to select a data rate. The rate selector comprises an input configured to receive input bits and an output to provide the bits with the selected data rate. The transmitter further comprises a bit to symbol mapper configured to receive the bits from the rate selector and map the bits to symbols of an arbitrary alphabet. The transmitter further comprises a spreading unit configured to spread the symbols received from the bit to symbol mapper to a chip sequence by means of a spreading code. The transmitter further comprises a re-mapping unit configured to map the chip sequence received from the spreading unit to produce signals for providing to the modulator.

A near-field capacitive data communication system that uses a variable capacitive device such as a PIN diode to change the capacitance of a conductive plate in response to either a high or low data signal. A detector attached to a second conductive plate that is in proximity to the first conductive plate measures the capacitance of the first conductive plate and outputs a corresponding data signal. The technique is wireless, since the two conductive plates are not in electrical contact with one-another, but rather share their static electric fields. A microcontroller can act as a detector by baselining the capacitance of the first conductive plate when its capacitance is in the low capacitance state. The technique is ideal for communication between a pair of toys that can be brought in close proximity to one-another. Since no radio frequencies are used, no special testing or governmental electromagnetic compatibility rules apply.

A digital receiver being adapted for receiving an MSK modulated signal, comprises a digital front-end unit (10) adapted for providing samples having a phase value (.sub.measure) of a down-mixed signal, a phase compensation unit (11) adapted for compensating the phase value (.sub.measure) by delivering a phase offset compensated sample having a phase value (.sub.sync), and a coherent demodulator (12) adapted for recovering information content from the phase offset compensated sample. The phase compensation unit (11) is adapted for analyzing a phase value (.sub.sync) of the phase offset compensated sample, calculating a phase offset value (.sub.offset) based on the phase value (.sub.sync) of the phase offset compensated sample, and applying the phase offset value (.sub.offset) when delivering a subsequent phase offset compensated sample.

A wireless transmitter for transmitting bits to a wireless receiver. The wireless transmitter comprises: (i) circuitry for generating binary data bits; and (ii) circuitry for providing a first spreading sequence for a first bit in the binary data bits and for providing a second spreading sequence for a second bit in the binary data bits, wherein the second bit is complementary to the first bit. Each spreading sequence consists of an integer number N of bits, and the circuitry for providing provides a same bit value in an integer number M of bit positions in the first and second spreading sequences, where M<N.

A transmitter in a first wireless communication device and method therein are disclosed. The transmitter comprises a modulator and a rate selector configured to select a data rate. The rate selector comprises an input configured to receive input bits and an output to provide the bits with the selected data rate. The transmitter further comprises a bit to symbol mapper configured to receive the bits from the rate selector and map the bits to symbols of an arbitrary alphabet. The transmitter further comprises a spreading unit configured to spread the symbols received from the bit to symbol mapper to a chip sequence by means of a spreading code. The transmitter further comprises a re-mapping unit configured to map the chip sequence received from the spreading unit to produce signals for providing to the modulator.

A radio network node comprised, and a wireless device configured to be operative, in a wireless communication system. The radio network node obtains downlink data and converts it to a baseband signal. The conversion comprises Gaussian Minimum Shift Keying (GMSK) modulation of the downlink data. The modulation applies a negative modulation index selected based on a type of wireless device that is a target for the downlink data. A radio signal is provided based on the baseband signal and sent to, and received by, the wireless device that provides user data based on the radio signal.

A wireless transmitter for transmitting bits to a wireless receiver. The wireless transmitter comprises: (i) circuitry for generating binary data bits; and (ii) circuitry for providing a first spreading sequence for a first bit in the binary data bits and for providing a second spreading sequence for a second bit in the binary data bits, wherein the second bit is complementary to the first bit. Each spreading sequence consists of an integer number N of bits, and the circuitry for providing provides a same bit value in an integer number M of bit positions in the first and second spreading sequences, where M<N.