Abstract:
Systems and methods are disclosed that may detect a likely presence of a narrow band signal in the presence of wide-band interference without powering up a wireless receiver. A wireless device may receive a wireless signal, measure a first energy level in a first frequency band associated with an expected frequency band of the narrow band wireless signal, measure a second energy level in a second frequency band that is offset from and non-overlapping with the first frequency band, and determine whether a difference between the first energy level and the second energy level exceeds a threshold. A wireless receiver of the wireless device may be powered up based at least in part on the difference between the first energy level and the second energy level exceeding the threshold.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
Systems, methods, and devices for wireless communication are included herein. An aspect of the subject matter described in the disclosure provides a device configured to detect a transmission. The device includes a receiver configured to receive an inductive communication signal having a center frequency. The device further includes an analog-to-digital converter configured to sample the signal at a rate higher than twice the center frequency. The device further includes one or more processors configured to digitally downconvert the signal. The processors are further configured to compare an energy of the downconverted signal to a detection threshold. The device further includes a transmitter configured to selectively transmit a communication based on the comparison.
Abstract:
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.
Abstract:
Systems, methods, and devices for determining an acquisition threshold boundary value and applying that boundary value to identify which incoming signals are directed to a device, based on matching the device syncword with the syncword for the incoming signal. For some implementations using ANT protocol, syncwords composed of the last four bits of the preamble and first 14 bits of the network address identify each device. Incoming syncwords are correlated with the device's syncword, and the correlation compared to threshold boundary value which is based on the characteristics of the individual syncword, including syncword bit stream inter-symbol interference.
Abstract:
A method for wireless communication is described. The method includes receiving a signal that is pattern-mapped and Gaussian frequency-shift keying (GFSK) modulated. The method also includes performing a joint demapping and demodulation of the received signal based on a stored accumulated phase. The method may further include updating the stored accumulated phase based on the joint demapping and demodulation.
Abstract:
A method of joint demodulating and demapping of a digital signal includes receiving a first sequence of the digital signal. The digital signal has a pattern in which a norm of an ideal transmitted sequence of symbols for zero is equal to a norm of an ideal transmitted sequence of symbols for one. The method also includes defining a portion of the first sequence as a third sequence, determining, for each element of a set of the third sequence, one of a real part of a value or an imaginary part of the value of the element, calculating a value for a combination of the determined one of the real part of the value or the imaginary part of the value for the each element of the set, and setting a bit equal to one in response to the value for the combination being less than zero.
Abstract:
Multiple input multiple output (MIMO) communication systems and methods for chip to chip and intrachip communication are disclosed. In one aspect, MIMO techniques that have been applied to wireless communication systems are applied to interchip and intrachip communication systems. In particular, a transfer function is applied at the transmitter, and a reverse transfer function is applied at the receiver. The transfer function dynamically changes based on channel conditions to cancel or otherwise mitigate electromagnetic interference (EMI) and crosstalk conditions. In an exemplary aspect, a sum of power levels across the channels may have a maximum. To abide by such power level constraint, the transfer function may be optimized to reduce interference while remaining within the power level constraint.