Abstract:
A mechanism for retrieval of carrier frequency and carrier phase in a received modulated carrier waveform. Retrieval of carrier frequency and carrier phase can be implemented in an analog electrical circuit, using a field programmable gate array (FPGA), or in computer code. Independent of the implementation, the mechanism performs frequency and primary phase recovery by forcing transforms of a pilot tone in the upper and lower sidebands to the same frequency using a feedback loop. The difference-in-magnitudes of the channelized pilot are used by a phase lock loop to perform secondary phase recovery in a manner that also resolves phase sign ambiguity. Benefits of this mechanism include improved phase lock loop tracking performance and a reduction of noise in the data demodulated from the received carrier waveform.
Abstract:
A receiver may comprise: a symbol receiver configured to receive a first modulated symbol at a first resolution and thereafter a second modulated symbol at a second resolution greater than the first resolution; an output path coupled to the symbol receiver and configured to forward the first modulated symbol; a decision device coupled to the symbol receiver and configured to determine a most probable symbol represented by the first modulated symbol;a phase detector coupled to the decision device and configured to compare the first modulated symbol and the most probable symbol to generate a phase error value; and a phase modifier coupled to the decision device and configured to determine a phase correction value based on the phase error value and to adjust the phase of the second modulated symbol based on the phase correction value.
Abstract:
The present invention relates to a method and apparatus for monitoring a downlink control channel by a first terminal having a single RX chain in a wireless communication system. Specifically, the present invention comprises the steps of: setting a particular gap for a resource area related to device-to-device (D2D) signal transmission/reception; and monitoring a wide area network (WAN) communication-based downlink control channel on the basis of a timer performed according to a discontinuous reception (DRX) operation, wherein the timer is counted on the basis of at least one subframe which does not overlap with the particular gap, and the particular gap is a time interval set for allowing the single RX chain to cover a switching operation between WMN communication and D2D communication.
Abstract:
A system, method and computer program product are provided for demodulating Quadrature Amplitude Modulated (QAM) signals based upon a speed of a receiver. The system includes a receiver and a demapping element. The receiver is capable of receiving a QAM signal over at least one slot. The demapping element can then be capable of estimating the amplitude of a signal constellation of the QAM signal over either one or more of the slot(s) or fractions of the slot(s) based upon the speed of the receiver. More particularly, the demapping element can estimate the amplitude by first estimating an expectation of a power of a signal combination of a traffic symbol and a pilot symbol, where the expectation can be estimated over either one or more of the slot(s) or fractions of the slot(s). The demapping element can also estimate a bias, and thereafter estimate the amplitude based upon the expectation of the power of the signal combination and the bias.
Abstract:
A synchronous detector (200) has first and second mixer circuits (206, 208) and a voltage-controlled oscillator (212). The voltage-controlled oscillator provides a local oscillator signal directly to the second mixer circuit and indirectly to the first mixer circuit through a phase transformer (210). The output of the first and second mixer circuits are combined in a combiner circuitry (220) to produce a jitter cancelled output signal. The jitter cancelled output signal is filtered in a loop filter (214) and applied to the voltage-controlled oscillator to control the frequency and phase of the local oscillator signal. The combiner circuitry includes a summer (222) and a jitter cancellation filter (228). The jitter cancellation filter is preferably a high pass filter matched to spectrum of the signal detected. The output of the first mixer circuit is passed through the high pass filter into one input of the summer while the output of the second mixer circuit is passed to the second input of the summer. The output of the summer is passed to the loop filter.
Abstract:
The present invention relates to a method and apparatus for monitoring a downlink control channel by a first terminal having a single RX chain in a wireless communication system. Specifically, the present invention comprises the steps of: setting a particular gap for a resource area related to device-to-device (D2D) signal transmission/reception; and monitoring a wide area network (WAN) communication-based downlink control channel on the basis of a timer performed according to a discontinuous reception (DRX) operation, wherein the timer is counted on the basis of at least one subframe which does not overlap with the particular gap, and the particular gap is a time interval set for allowing the single RX chain to cover a switching operation between WMN communication and D2D communication.