Patent application number | Description | Published |
20100260233 | PHASE TRACKING IN FREQUENCY DOMAIN IN A WIRELESS COMMUNICATION SYSTEM - Techniques for correcting sampling frequency offset (SFO) and carrier frequency offset (CFO) in a wireless communication system are disclosed. An apparatus for correcting SFO and CFO may include a pilot tone extractor for extracting a plurality of pilot tones from one or more first symbols, a demodulator, an error signal generator, a loop filter, an angle generator, and a device for applying a correction phase to one or more symbols subsequent to the one or more first symbols. The demodulator is configured to demodulate the pilot tones. The error signal generator is configured to generate an error signal by summing and calculating the arctangent of the plurality of demodulated pilot tones. The loop filter is configured to generate an estimated phase rotation due to a residual CFO and the angle generator is configured to generate a correction phase for the plurality of tones. | 10-14-2010 |
20140062588 | SYSTEM AND METHOD TO DEMODULATE A LOAD MODULATED SIGNAL - A method includes demodulating a load modulated signal at an initiator device based at least partially on a phase adjusted comparison value corresponding to the load modulated signal. | 03-06-2014 |
20140073241 | METHODS AND APPARATUS FOR IMPROVING ACQUISITION FOR NFC LOAD MODULATION - Aspects disclosed herein relate to improving acquisition for NFC load modulation. In one example, a communications device is equipped to monitor at least a complex component of load modulation of a carrier signal, detect, using a NFC technology type specific peak detection scheme, a peak associated with at least the complex component, and determine a presence of a packet beginning pattern based on the detected peak. In an aspect, the packet beginning pattern may be associated with a reception of a packet from a target NFC device. | 03-13-2014 |
20140086292 | SYSTEMS AND METHODS FOR DETECTING DATA COLLISIONS FOR A NEAR FIELD COMMUNICATION SYSTEM - In a wireless near field communication (NFC) system, a target, such as a smart card, can communicate with an initiator, such as a card reader, by load modulating a radio frequency (RF) signal generated by the initiator. When two or more targets load modulate the RF signal generated, “collisions” can occur with the load modulation. Apparatus and methods detect the presence or absence of collisions in a lower layer or physical layer and report the presence of detected collisions to an upper layer for further handling. | 03-27-2014 |
20140098913 | SYSTEM AND METHOD FOR I-Q IMBALANCE CORRECTION - Systems and methods are disclosed for compensating I-Q imbalance in a wireless receiver. The receiver may employ a quadrature downconverter configured to receive an RF signal input and output an in-phase component and a quadrature component at an IF, an IF rotation block configured to downconvert the in-phase and quadrature components to baseband and an I-Q correction block configured to compensate for an I-Q imbalance in the received signal, wherein the I-Q correction block is positioned downstream from the IF rotation block in the signal path. Performing the I-Q correction after conversion to baseband may allow the compensation calculations to operate at a reduced digital rate. Similarly, digitally adjusting the gain of the signal prior to I-Q compensation may reduce the number of bits that are manipulated during the compensation process. These features may represent significant efficiencies as compared to I-Q corrections performed at IF. | 04-10-2014 |
20140321581 | METHODS AND SYSTEMS TO DETECT THE OCCURRENCE OF ERRONEOUS DEMODULATED BITS FOR DECISION FEEDBACK DEMODULATION - Systems and methods to detect the occurrence of erroneous demodulated bits for decision feedback demodulation are disclosed. In one implementation, an apparatus for detecting demodulation bit errors of a plurality of modulated bits includes a memory component configured to store a first threshold and a second threshold. The apparatus further includes a processor coupled to the memory component, the processor configured to retrieve the first threshold and second threshold from the memory component and to determine a demodulation metric value for each of the plurality of modulated bits, the processor further configured to count the number of demodulation metric values that cross the first threshold and compare the second threshold to the number of demodulation metric values that cross the first threshold. | 10-30-2014 |
20150124906 | SYSTEMS AND METHODS FOR IMPROVING COMMUNICATION SENSITIVITY - A method for improving communication sensitivity by a wireless communication device is described. The method includes obtaining a string of bits. The method also includes mapping each bit in the string of bits to a pre-allocated bit pattern to create a series of concatenated pre-allocated bit patterns. The method further includes generating a modulated signal based on the series. The method additionally includes transmitting the modulated signal. | 05-07-2015 |
20150133069 | FM RECEIVER WITH FREQUENCY DEVIATION-DEPENDENT ADAPTIVE CHANNEL FILTER - Methods, systems, and devices are described for wireless communications in a frequency modulation (FM) receiver with a frequency deviation-dependent adaptive channel filter. A maximum frequency deviation of an FM broadcast signal may be estimated. One or more coefficients of a channel filter may be adapted based at least in part on the maximum frequency deviation. The coefficient adaptation may include identifying a set of coefficients corresponding to the maximum frequency deviation and applying the set of coefficients to the channel filter. The set of coefficients may be identified by selecting one of multiple sets of coefficients stored in memory. In some instances, a signal quality metric (e.g., signal-to-noise ratio (SNR)) may be identified and may be used to modify a value of one or more of the set of coefficients applied to the channel filter. | 05-14-2015 |