Abstract: A wireless communication method includes determining whether a wireless device desires dynamic sounding reference signal (SRS) resources and providing, based on the determination, a dynamic SRS resource allocation to the wireless device.

Abstract: An apparatus and method for compensating for duty signals are disclosed herein. The apparatus for compensating for duty signals includes a signal input unit, a signal control unit, a combined signal control unit, a determination unit, and a signal output unit. The signal input unit receives a first signal and a second signal. The signal control unit controls the timing of the first and second signals based on first and second control signals, and outputs a combined signal. The combined signal control unit outputs first and second logic operation signals. The determination unit generates the first and second control signals if the timing of the first signal does not match the timing of the second signal, outputs the generated first and second control signals, and applies a third control signal to the combined signal control unit. The signal output unit outputs the first and second signals.

Abstract: A quadrature mixer arrangement is disclosed, which is adapted to translate an input signal by a translation frequency. The mixer arrangement is operated at a clock rate that equals the translation frequency times an oversampling rate, wherein the oversampling rate is not a multiple of four. The mixer arrangement comprises a sequence generator, at least one pair of mixers, and one or more correction networks. The sequence generator generates an in-phase mixer translation sequence and a quadrature-phase mixer translation sequence based on the oversampling rate. The in-phase mixer translation sequence is a time-discrete representation of a translation frequency sinusoidal function sampled at the clock rate, and the quadrature-phase mixer translation sequence is a time-discrete representation of the translation frequency sinusoidal function phase-shifted by ?/2 plus a phase deviation and sampled at the clock rate, wherein the phase deviation is a function of the oversampling rate.

Abstract: Multiuser classification of the modulation schemes of simultaneous multiple unknown transmitters is disclosed. Cooperation among multiple cognitive radio receivers for modulation classification offers improvements in classification performance and overcomes detrimental channel effects that degrade single cognitive radio classifier performance. A centralized soft-combining data fusion algorithm based on the joint probability distribution of fourth order cumulants is presented for cooperative modulation classification. Fourth order cumulants of received signals are calculated as discriminating features for different modulation schemes at each cognitive radio node and sent to a centralized data node. The data node chooses the modulation scheme that maximizes the joint probability of the estimated cumulants.

Abstract: Embodiments for providing demodulation reference signals to provide side information for interference cancellation are generally described herein. In some embodiments, a sub-frame is prepared comprising two slots and configuring a physical resource block (PRB) for each slot, wherein each PRB comprises twelve Orthogonal Frequency Division Multiplexing (OFDM) subcarriers transmitting for a duration of 7 OFDM symbols per slot. In resource elements on each of three of twelve OFDM subcarriers, two pairs of demodulation reference signals (DMRS) are allocated to form three DMRS sets. Symbols are mapped with a first modulation for the two pairs of demodulation reference signals to three of the twelve OFDM subcarriers for transmission. A second modulation is added to a first of the three DMRS sets and a third modulation is added to a second of the three DMRS sets to indicate side information regarding an interfering signal for use in mitigating the interfering signal.

Abstract: A transmitter circuit includes a frequency generation circuit configured to generate a local oscillator signal and a digital modulator configured to: receive data to be transmitted; quadrature modulate the received data to at least a first, Q, modulated value and a second, I, modulated value; examine the quadrature modulated data to determine if the first, Q, modulated value exceeds a limit, and in response thereto selectively modify the quadrature modulated values to a first modified, Q?, modulated value and a second modified, I?, modulated value thereby bringing only a value of the first modified, Q?, modulated value to within the limit. A local oscillator phase is selected in order to map the first modified, Q?, modulated value and second modified, I?, modulated value to desired quadrature values. A digital power amplifier, DPA, coupled to the digital quadrature modulator, is configured to amplify the quadrature modified modulated data.

Abstract: A digital frequency modulation receiver includes a phase capturer, an adder, a digital filter and a phase estimator. The phase estimator is used to generate a first phase value according to an input signal. The adder is coupled to the phase estimator for subtracting a second phase value from the first phase value to generate a phase difference. The digital filter is coupled to the adder for performing a filtering calculation with the phase difference so as to generate a frequency variation signal. The phase estimator is coupled to the digital filter and the adder so as to update the second phase value according to the frequency variation signal.

Abstract: A frequency modulation circuit includes a calibration-operating part which calculates primary calibration values of modulation index at central frequencies of respective ones of n pieces of TF bands which constitute the entire TF range. Interpolation-calculation part performs an interpolation-calculation with respect to the n pieces of primary calibration values and calculates calibration values at intermediate frequencies of central frequencies of neighboring ones of TF bands while calculating calibration values at frequencies at both ends of entire TF range to obtain (n+1) pieces of interpolated calibration values as secondary calibration values. Calibration value supply part supplies one calibration value corresponding to the TF bands set in the TF band setting part from among the primary calibration values or secondary calibration values to a modulation part performing frequency modulation together with calculation based on the supplied calibration value.

Abstract: A method for reducing the peak-to-average ratio in an OFDM communication signal is provided. The method includes defining a constellation having a plurality of symbols, defining a symbol duration for the OFDM communication signal, and defining a plurality of time instants in the symbol duration. A plurality of tones are allocated to a particular communication device, and a discrete signal is constructed in the time domain by mapping symbols from the constellation to the time instants. A continuous signal is generated by applying an interpolation function to the discrete signal such that the continuous signal only includes sinusoids having frequencies which are equal to the allocated tones.

Abstract: A receiver for high speed communications. The receiver includes an analog to digital converter to convert an analog input signal into at least one digital input signal at timings controlled by a sampling clock. A finite impulse response filter generates at least one filtered input signal based on the digital input signal. A data decision circuit recovers data based on the filtered input signal. The filtered input signal and the recovered data can be provided to a feedback loop to determine a timing error of the sampling clock, which is then used to generate the sampling clock.

Abstract: Handling a frequency error (FEQ) of a terminal which includes a plurality of modems using a same clock source includes: obtaining the FEQ, which is a difference between a carrier frequency of a received signal and a nominal frequency for each modem; obtaining a FEQ threshold of the received signal in a current service based on the FEQ; obtaining an adjusted value of the clock source corresponding to each modem based on the FEQ and the FEQ threshold; obtaining a synthesized adjusted value of the clock source based on the adjusted values of all the modems; and adjusting the frequency of the clock source based on the synthesized adjusted value of the clock source. The FEQ of the mobile communication terminal can be quickly corrected by adjusting the clock source's frequency, and, by considering the FEQ of all the modems, the modems' performances may be balanced.

Abstract: A quadrature detector quadrature-detects an FM signal. A first reducer and a second reducer reduce a direct current component included in the FM signal quadrature-detected in the quadrature detector. An FM detector generates a detection signal by FM detecting the FM signal in which the direct current component has been reduced by the first reducer and the second reducer. The offset unit adds an offset to the detection signal generated in the FM detector. An AFC unit generates a control signal for controlling the frequency of a local oscillation signal used in the quadrature detector on the basis of the detection signal to which the offset has been added by the offset unit and feeds back the control signal to a local oscillator that should output the local oscillation signal.

Abstract: A method in which a terminal (UE) operates to perform channel quality measurement in a system which supports carrier aggregation, disclosed in the present description, comprises the following steps: receiving, from a base station, a first message containing a first indicator for indicating control information for channel quality measurement used in an extension component carrier; receiving control information corresponding to the first indicator from the base station via the extension component carrier; and performing channel quality measurement in the extension component carrier using the received control information.

Abstract: First and second inputs are received. The first input indicates a frequency offset of a frequency band allocated for signal transmission. The said allocated band is a subband of a total band available for transmission. The second input indicates a bandwidth of the allocated band. One or more filters of a transmitter of a communications system are controlled to operate cumulatively in a lowpass filtering mode, wherein the highest frequency in a pass band in the lowpass filtering mode is less than the highest frequency of the total band available for transmission. A signal is filtered using the filter(s).

Abstract: Systems and methods for a self-optimizing distributed antenna system are provided. In certain embodiments, a distributed antenna system comprises a host unit configured to control the operation of the distributed antenna system; and a plurality of remote units coupled to the host unit. In at least one embodiment, a remote unit in the plurality of remote antenna units comprises a scanning receiver configured to receive signals in a plurality of frequency bands; at least one transceiver configured to transmit and receive signals in a frequency band in the plurality of frequency bands; and a remote unit controller configured to control an uplink gain level of the at least one transceiver and tune the scanning receiver to a frequency band in the plurality of frequency bands.

Abstract: A direct conversion receiver device may receive I and Q signals. The direct conversion receiver device may include a blind IQ balance circuit configured to balance the I and Q signals without a pilot signal, and a mixer coupled to the blind IQ balance circuit and configured to generate I and Q baseband signals using an operational frequency, the operational frequency being based upon bandwidth and modulation of the I and Q signals. The blind IQ balance circuit may include a first stage configured to generate an intermediate amplitude balanced Q signal based upon the I and Q signals, and a second stage coupled to the first stage and configured to generate phased balanced I and Q signals based upon the intermediate amplitude balanced Q signal and the I signal.

Abstract: A technique for calibrating a receiver apparatus comprising at least one analog signal processing component and an intermediate frequency, or IF, mixer for converting IF signals comprising an in-phase, or I, signal and a quadrature-phase, or Q, signal to baseband frequency signals is provided. The IF mixer is arranged downstream of the at least one analog signal processing component. A method implementation of the technique comprises the steps of determining, in a digital processing domain downstream of the IF mixer, a metric which is affected by a frequency dependency of an imbalance between I and the Q signal, or IQ-imbalance, over a signal bandwidth, generating, based on the metric thus determined, a calibration signal configured to at least partially compensate a frequency-dependency of the IQ imbalance, and feeding the calibration signal to the at least one analog signal processing component so as to calibrate the at least one analog signal processing component.

Abstract: An integrated optical linewidth reduction system includes a phase modulator adapted to modulate the phase of an incoming optical signal in response to a feedback control signal defined by a first electrical signal. The phase modulator is further adapted to generate a first optical signal travelling through a first optical path. The first electrical signal is representative of a phase noise of the first optical signal. An optical linewidth of the first optical signal is less than an optical linewidth of the incoming optical signal.

Abstract: A method for wireless communication is described. A slow associated control channel block is received. It is determined that the slow associated control channel block fails an integrity check. A correlation level between the slow associated control channel block and one or more stored slow associated control channel blocks is determined. The stored slow associated control channel blocks are set based on a maximum correlation level. Other aspects, embodiments, and features are also claimed and described.

Abstract: There is a need to reduce secondary intermodulation distortion that may occur in a reception circuit of a high-frequency signal processor and a wireless communication system having the same. In test mode, for example, a test signal generating circuit TSGEN generates a test signal RFtst at f_tx±0.5 MHz. The test signal RFtst is input to a mixer circuit MIXrx_I (MIXrx_Q). A correction circuit block CALBK detects an IM2 component resulting from the MIXrx_I (MIXrx_Q). The CALBK varies a differential balance for the MIXrx_I (MIXrx_Q) and concurrently monitors a phase for the IM2 component resulting from MIXrx_I (MIXrx_Q). The CALBK searches for the differential balance corresponding to a transition point that allows the phase to transition by approximately 180°. The MIXrx_I (MIXrx_Q) operates in normal mode using the differential balance as a search result.

Abstract: Systems and methods are disclosed for estimating one or more channel properties of a downlink from a cellular communications network based on quasi co-located antenna ports with respect to the one or more channel properties. In one embodiment, a wireless device receives a downlink subframe including a downlink control channel from the cellular communications network. The wireless device estimates one or more large-scale channel properties for an antenna port of interest in the downlink control channel based on a subset of reference signals that correspond to antenna ports in the cellular communications network that are quasi co-located with the antenna port of interest with respect to the one or more large-scale channel properties. As a result of using the quasi co-located antenna ports, estimation of the one or more large-scale channel properties is substantially improved.

Abstract: A method and an apparatus for detecting an envelope using a difference between sampling signals are provided. The method includes generating sampling sets based on sampling signals of a modulated signal, and determining a sampling set from the sampling sets. The method further includes determining an envelope component value associated with a sampling signal among sampling signals included in the determined sampling set, based on a difference between the sampling signals included in the determined sampling set, and a difference between sampling signals included in each of the sampling sets other than the determined sampling set. The method further includes detecting an envelope of the modulated signal based on the envelope component value.

Abstract: Methods and systems for I/Q mismatch calibration and compensation for wideband communication receivers may include receiving a radio frequency (RF) signal in a receiver of a communication device, down-sampling the received RF signal to generate a channel k and its image channel ?k at baseband frequencies, and determining average in-phase (I) and quadrature (Q) gain and phase mismatch of the channel k and the image channel ?k. A curvature of gain mismatch for the channel k and the image channel ?k may be estimate utilizing a blind source separation (BSS) estimation algorithm. The average I and Q gain and phase mismatch of the channel k and the image channel ?k may be removed. A residual phase tilt and a residual amplitude tilt of the channel k and the image channel ?k (with removed average I and Q gain and phase mismatch) may be determined.

Abstract: A communications system comprising a communications media. A receiver coupled to the communications media and configured to receive a data signal from the communications media. An adaptive equalizer configured to process the data signal and to adjust a multi-frequency inverse transfer function to compensate for a multi-frequency transfer function of the communications media.

Abstract: Disclosed are a method and apparatus for estimating symbol timing in a non-synchronized OFDM system. The present invention includes synchronizing a frame of a received signal, estimating the symbol timing of each symbol of the frame based on the synchronization, compensating for the symbol timing using a phase difference attributable to a Symbol Timing Offset (STO), variably changing within a Cyclic Prefix (CP) interval due to the frequency offset of a sampling clock and thermal noise, and performing channel equalization using a preamble based on output including corrected phase rotation.

Abstract: Proposed is a method of deriving differentially decoded data values from a received differentially encoded phase modulated optical signal. The method uses an estimation algorithm in order to find derive a sequence of differentially decoded data values. The algorithm stipulates transition probabilities between hypothetical first states, representing differentially encoded data symbols assuming that no phase slip has occurred, and transition probabilities towards hypothetical second states, which represent differentially encoded data symbols assuming that a phase slip has occurred. The transition probabilities between the first and second states are weighted on the basis of a predetermined phase slip probability value.

Abstract: A receiver and method is provided for sigma-delta converting an RF signal to a digital signal and downconverting to a digital baseband signal. The RF signal is split into N phases, as can be accomplished using a sample and hold circuit, and each phase is digitized, as can be accomplished using an analog-to-digital (A/D) sigma-delta converter. Polyphase decimation techniques and demodulation are applied to the phased signals to generate a demodulated digital signal. The demodulated digital signal is further downconverted to the appropriate baseband signal.

Abstract: A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus generates a codeword, determines at least one puncture to the codeword based on allowing a legacy receiver to decode the codeword without knowledge of the at least one puncture, replaces each of the at least one puncture with a pilot, and transmits the codeword. The apparatus may also generate an IEEE 802.11 codeword having pilots in a first set of subcarriers, and puncture the codeword with additional pilots unknown to a legacy receiver in a second set of subcarriers. Accordingly, when an original set of pilot symbols is insufficient or inappropriately placed in a resource structure, a codeword may be transmitted with a new pilot structure capable of being decoded by legacy receivers not aware of the new pilot structure.

Abstract: A blind mode adaptive equalizer system to recover the in general complex valued data symbols from the signal transmitted over time-varying dispersive wireless channels is disclosed comprising an adaptive communication receiver for the demodulation and detection of digitally modulated signals received over wireless communication channels exhibiting multipath and fading, the receiver comprising an RF front end, an RF to complex baseband converter, a band limiting matched filter, a channel gain normalizer, a blind mode adaptive equalizer with hierarchical structure, an initial data segment recovery circuit, a differential decoder, a complex baseband to data bit mapper, and an error correction code decoder and de-interleaver.

Abstract: Certain aspects of the present disclosure provide methods and apparatus for performing quadrature combining and adjusting. One example circuit may include first through fourth mixing circuits. The first mixing circuit may multiply a radio frequency signal with a first local oscillating signal to generate a first frequency converted signal. The second mixing circuit may multiply a radio frequency (RF) signal with a second local oscillating signal, which may be about 90° out of phase with the first local oscillating signal, to generate a second frequency converted signal. The third and fourth mixing circuits may multiply the RF signal with the second and first signals, respectively, to generate third and fourth frequency converted signals, respectively. A first combining circuit may combine the first and third frequency converted signals, and a second combining circuit may combine the second and fourth frequency converted signals.

Abstract: A method for generating interference signals and a device to carry out said method, in which an interference signal (1) is added in a signal combination and separation network (3) with a desired signal (4) that carries a test message, the sum signal being sent to a device being tested (5). The interference signal (1) is generated with a single source connected to a signal divider and conditioner block (7) that attenuates additional interference produced by the source of generation of interference signals (1), while providing as many interference signals (1) as the device (5) under test has antennas (Rx, Rx/Tx), and in which each interference signal (1) is sent to a respective amplification and isolation block (8), which adjusts the power level of the interference signal (1) and attenuates the reverse intermodulation products produced by the transmission of signals by the device (5) under test.

Abstract: A phase comparison circuit includes: a first flip-flop configured to receive a data signal and a clock signal; a second flip-flop configured to receive an output signal of the first flip-flop and a signal that is an inversion of logic of the clock signal; a delay circuit configured to give delay time to the data signal, in which the delay time is equal to or longer than signal delay time from a clock terminal of the first flip-flop to a Q output terminal of the first flip-flop; a first exclusive OR circuit configured to receive an output signal of the delay circuit and the output signal of the first flip-flop; and a second exclusive OR circuit configured to receive the output signal of the first flip-flop and an output signal of the second flip-flop.

Abstract: A phase offset compensator for compensating a phase offset is provided. The phase offset includes a first phase sub-offset and a second phase sub-offset. The phase offset compensator includes a feedback loop comprising a first loop filter, the feedback loop being configured to compensate the first phase sub-offset of the phase offset, and a feed forward loop comprising a second loop filter, the feed forward loop being configured to compensate the second phase sub-offset of the phase offset.

Abstract: Disclosed are methods and a device for Multi-resolution PMI Feedback. In one implementation, a user equipment finds a rank 1 or rank 2 Precoding Matrix Indicator based on the signal channel matrix and interference covariance matrix, defines an error vector, obtains an orthonormal basis for the projection matrix, finds the (M?1)-dimensional vector from a codebook (e.g., oversampled Discrete Fourier Transform) with the minimum Euclidean distance, and sends a feedback representing to the base station regarding the vector that it found in the codebook.

Abstract: A receiving device including: a demodulation circuit configured to generate first likelihood data of reception symbols based on a transmission format of the reception symbols, the transmission format being selected from transmission formats and including a modulation scheme applied to the reception symbols, the modulation scheme being one of amplitude modulation schemes, a processor configured to estimate a scale ratio of an implementation scale to a theoretical scale, the implementation scale being a scale of the first likelihood data, the theoretical scale being a scale of second likelihood data of the reception symbols, the second likelihood data being defined by a theory and not depending on an implementation of the receiving device, and to generate the second likelihood data based on the first likelihood data and the scale ratio, and a decoding circuit configured to decode the second likelihood data based on the transmission format.

Abstract: This disclosure presents a receiver apparatus (10) and corresponding method that advantageously use ISI-canceling combining weights, as are generated for ISI suppression in the receiver's data signal combining operations, to suppress the effects of ISI from determinations of receiver frequency error. Such suppression yields more accurate receiver frequency error determination and, correspondingly, improved receiver frequency error compensation.

Abstract: Systems and methodologies are described that facilitate dynamically allocating demodulation resources of a wideband receiver to provide improved demodulation of simultaneously received signals. Signal-to-noise ratio (SNR) and/or packet error rate (PER) can be measured for the plurality of carriers to determine which demodulators related to the carriers require more resources than others to demodulate signals at a specified signal quality. Where the SNR of a related carrier is high and/or PER is low, the demodulator can require fewer resources than where the SNR of a related carrier is low and/or PER is high. In this regard, the resources are dynamically allocated among the demodulators and reallocated where SNR/PER changes and/or additional resources are made available.

Abstract: A receiver front end circuit includes a low-noise amplifier including: a first receiver path having: a first low-noise transconductor to amplify a received signal and output the amplified received signal; and a first mixer to down-convert the amplified received signal. A second receiver path includes: an auxiliary receiver having: a second transconductor to output an amplified received signal; a baseband amplifier having an input port and an output port; a first resistance coupling the input port to the output port of the baseband amplifier and to convert the amplified received signal from current to voltage and set a voltage gain of the second receiver path; and a second resistance coupled from the output port of the baseband amplifier to the first mixer output. In some examples, frequency-upconversion feedback path includes a third mixer to frequency up-convert the amplified received signal at an output of the second receiver path.

Abstract: Systems and methodologies are described that facilitate transmitting at least two different types of information in a single signal, whereby the different types of information can be encoded and decoded independently. Thus, changes to one type of information does not affect a second type of information.

Abstract: A communication apparatus, method, and system are provided. The communication apparatus receives through a transmission path a combined signal in which modulated signals are combined. The communication apparatus converts a channel matrix indicating transmission characteristics of the transmission path using a basis conversion matrix which converts column vectors forming the channel matrix to cross at right angles, estimates a transmission symbol using the converted channel matrix, and calculates a likelihood of each bit of the estimated transmission symbol being a “1” and a “0”, respectively, using an inverse matrix of the basis conversion matrix. The method includes converting a channel matrix; estimating a transmission symbol; and calculating a likelihood of each bit being a “1” and a “0”, respectively, of the estimated transmission symbol using a basis conversion matrix. The system includes a transmitter and receiver for transmitting and receiving, respectively, a combined signal according to the method.

Abstract: One embodiment relates to a low intermediate frequency (IF) receiver. The low-IF receiver includes an analog front end that is configured to receive a modulated IQ data signal and provide an in-phase signal and a quadrature signal, where the in-phase signal is phase shifted by approximately 90° relative to the quadrature signal. The low-IF receiver further includes a digital processing block, and a single path that provides only one of the in-phase signal and the quadrature signal to the digital processing block. Other receivers and methods are also disclosed.

Abstract: A method of canceling sinusoidal interference from a received signal includes identifying a block of signal-free data containing sinusoidal interference. A model of the significant interference in the selected data block is constructed, scaled to subsequent data blocks and used to remove sinusoidal interference signals from the overall received signal.

Abstract: A satellite signal which carries a navigation message including satellite-specific information is received. Data of the navigation message is demodulated from received satellite signal. Error detection processing is carried out on demodulated data on a word basis of the navigation message. The number of bit transitions is counted at each corresponding bit transition position with respect to a first word in which an error is detected in the error detection processing and which carries the satellite-specific information, and plural second words belonging to a different frame from a frame to which the first word belongs and having a common part with the first word. A bit value of the first word is detected based on the number of bit transitions counted.

Abstract: One aspect of the present invention includes a bi-phase communication receiver system. The system includes an analog-to-digital converter (ADC) configured to sample a bi-phase modulation signal to generate digital samples of the bi-phase modulation signal. The system also includes a bi-phase signal decoder configured to decode the bi-phase modulation signal based on the digital samples. The system further includes a preamble detector comprising a digital filter configured to evaluate the digital samples to generate an output and to detect a preamble of the bi-phase modulation signal for decoding the bi-phase modulation signal based on the output.

Abstract: An ultra-low power super-regenerative receiver and method thereof are provided. The ultra-low power super-regenerative receiver includes a quench waveform generator configured to generate a quench waveform. The ultra-low power super-regenerative receiver further includes a super-regenerative oscillator configured to generate an oscillation signal based on the quench waveform. The ultra-low power super-regenerative receiver further includes a bandwidth adjustor configured to control the quench waveform based on a bandwidth of a signal received by the ultra-low power super-regenerative receiver, to dynamically adjust a bandwidth of the oscillation signal.

Abstract: In a method of allocating digital data (55a, 55b) coming from transponders, a reader (1) receives a first signal (13) that comprises a first signal component (7) coming from a first transponder (2) and a second signal component (8) coming from a second transponder (3). The digital data (55a) coming from the first transponder (2) are encoded in the first signal component (7) and digital data (55b) coming from the second transponder (3) are encoded in the second signal component (8). Second and third signals (10, 11) are generated by subjecting the first signal (13) to an in-phase and to an in-quadrature demodulation. The digital data (55a, 55b) of the first and second transponders (2, 3) are encoded in the second and third signals (10, 11). Clusters (51-54) of the digital data (55 a, 55b) associated with a constellation diagram, which is related to the second and third signals (10, 11), are allocated to the first and second transponder (2, 3).

Abstract: Embodiments of an apparatus for improving a gain imbalance between an in-phase and quadrature component recovered by a receiver are provided. The apparatus includes a first transition counter configured to count a number of bit transitions in a first sequence of one-bit values provided by a first sigma-delta modulator based on the in-phase component, and a second transition counter configured to count a number of bit transitions in a second sequence of one-bit values provided by a second sigma-delta modulator based on the quadrature component. The apparatus further includes a gain monitor configured to: (1) determine a first and second power level, proportional to a power of the in-phase and quadrature components respectively, using the number of bit transitions in the first and second sequences, and (2) adjust a gain of one of the in-phase and quadrature components based on a ratio between the first and second power levels.

Abstract: Methods and apparatus for timing synchronization based on transitional pilot symbols. In an aspect, a method is provided for time tracking synchronization in an OFDM system. The method includes receiving at least one TDM pilot symbol comprising a plurality of modulated sub-carriers that are configured to provide a channel estimate having a length that extends up to a duration of an FFT used for data transmission. The method also includes determining one or both of an instantaneous and averaged channel estimates from the plurality of modulated sub-carriers, and calculating a timing offset based on one or both of the channel estimates. An apparatus includes a receiver configured to receive the at least one TDM pilot symbol, a channel estimator configured to determine the instantaneous and averaged channel estimates, and a time synchronizer configured to calculate a timing offset based on the channel estimates.

Abstract: A method for calibrating mismatches of an in-phase signal path and a quadrature signal path of a transmitter, including: additionally configuration at least one mixer calibration coefficient at a transmitting part of the transmitter; obtaining at least one mixer testing signal from the transmitting part via loopback for spectrum analysis to derive at least one mixer spectrum analysis result; adjusting the mixer calibration coefficient of the transmitting part according to the mixer spectrum analysis result; and additionally utilizing an in-phase signal path finite impulse response filter and a quadrature signal path finite impulse response filter to calibrate mismatches between a low pass filter of the in-phase signal path of the transmitting part of the transmitter and a low pass filter of the quadrature signal path of the transmitting part of the transmitter. A similar mismatch calibration operation may be applied to a receiver.

Abstract: Logic may comprise a single phase tracking implementation for all bandwidths of operation and the logic may adaptively change pre-defined and stored track parameters if the receiving packet is 1 MHz bandwidth. Logic may detect a packet and long training fields before performing a 1 MHz classification. Logic may auto-detect 1 MHz bandwidth transmissions by a property of the long training field sequences. Logic may auto-detect 1 MHz bandwidth transmissions by detecting a Binary Phase Shift Keying (BPSK) modulated first signal field symbol rather than the Quadrature Binary Phase Shift Keying (QBPSK) associated with the 2 MHz or greater bandwidth transmissions. Logic may perform an algorithm to determine an estimated phase correction value for a given orthogonal frequency division multiplexing symbol and several embodiments integrate this value with an intercept multiplier that may be 0.2 for 1 MHz transmissions and, e.g., 0.5 for 2 MHz or greater bandwidth communication.