Nxp Usa, Inc.

Freescale Semiconductor,inc.

Mihai-Ionut Stanciu

Khurram Waheed

Raja Venkatesh Tamma

Claudio Gustavo Rey

Victor-Florin Crasmariu

Justin A Fritz

Kevin B Traylor

Ioan-Virgil Dragomir

Olivier Jean

Systems and methods for producing quality indicators for phase-based distance estimations using narrowband radios are described. In an illustrative, non-limiting embodiment, a device may include: a processor; and a memory coupled to the processor, the memory having program instructions stored thereon that, upon execution by the processor, cause the device to: measure a transfer function of a radio frequency (RF) channel between the device and another device using narrowband radios; estimate a distance between the device and the other device based, at least in part, upon the transfer function; and determine a Distance Quality Indicator (DQI) corresponding to the distance based, at least in part, upon an evaluation of a spectral lobe of the transfer function.

Distance quality indicator (DQI) for phase-based distance estimation using narrowband radios

A method for estimating a time-of-arrival of a packet received by a receiver includes storing a reference bit-pattern and receiving a plurality of samples in a samples-buffer. In a bit-pattern detector, a matching group of samples having a bit-pattern which matches the reference bit-pattern is identified. In a correlator, a group of three correlation values is determined from the matching group of samples, including a local maximum correlation value, P0, an immediately preceding correlation value, Pm, and an immediately succeeding correlation value Pp. In an estimation unit, a polynomial function f(&#x3b4;) of the difference, &#x3b4;, between Pm and Pp is used to estimate a timing offset T, between the local maximum correlation value and a correlation peak. The time-of-arrival is estimated from a time of the local maximum correlation value P0, and T.

Methods and apparatus for estimating a time-of-arrival or a distance between two device

Disclosed is receiver apparatus including a first input configured to receive a first signal, a second input configured to receive a second signal, a switching circuit configured to alternate between the first and second signal from the first and second inputs, a receiver configured to sample the input signal to produce a plurality of input samples, a reference sequence generator configured to generate a reference signal, and a correlator configured to correlate the first and second signals with the reference signal to detect a correlation event, the correlator including a first buffer configured to receive signals from the first input and a second buffer configured to receive signals from the second input, wherein the correlator is configured to process the first signal in the first buffer, while the second buffer receives the second signal.

Preamble detection in wireless systems with intermittent reception

An acquisition detector and method include a preamble detector configured to search in a plurality of symbols for a preamble match with a known preamble pattern when a power level of the input signal exceeds a determined noise threshold. The acquisition detector further includes a frame delimiter detector configured to search in the plurality of symbols for a frame delimiter match with a known frame delimiter pattern when the preamble match is identified and the power level of the input signal exceeds a determined noise threshold.

Acquisition of a data packet having a short preamble

A demodulator and method includes a plurality of correlation circuits, a result combining stage, and a time combining stage. The plurality of correlation circuits may be configured to output a plurality of correlation values that indicate a likelihood of whether a pattern of a buffered portion of an input data signal matches a first plurality of target frequency behavior patterns. The plurality of correlation circuits may be further configured to output a plurality of delayed correlation values that indicate a likelihood of whether a pattern of a delayed buffered portion of the input data signal matches a second plurality of target frequency behavior patterns, where both the buffered portion and the delayed buffered portion include a current symbol.

Symbol demodulator with error reduction

A method performed by a first wireless communication device is provided, which includes exchanging rate information with a second wireless communication device in response to a determination that the second wireless communication device is configured with the multi-rate extension mechanism, wherein the first and second wireless communication devices support two or more different data transfer rates that are faster or slower than a legacy data transfer rate specified by the legacy protocol; determining an appropriate data transfer rate based on the rate information and link quality information regarding a communication link between the first and second wireless communication devices; and communicating the appropriate data transfer rate to the second wireless communication device, wherein the appropriate data transfer rate is utilized during communication between the first and second wireless communication devices.

Multi-rate overlay mode in wireless communication systems

Processing of a data packet within a received wireless signal includes determining a frequency modulation ('FM') domain carrier frequency offset ('CFO') estimate component from a plurality of samples of the received wireless signal, determining a phase domain CFO estimate component from the plurality of samples of the received wireless signal, and determining a CFO estimation as a function of the FM domain CFO estimate component and the phase domain CFO estimate component. The data packet may be a Bluetooth Low Energy data packet. The FM domain CFO estimate component and the phase domain CFO estimate component may be determined from samples of a preamble field of the data packet.

Preamble detection mechanism for reception of asynchronous packets

Circuits and methods concerning signal detection are disclosed. In some example embodiments, an apparatus is configured to detect presence of a spreading sequence in a sample data sequence. Phase differences between samples in a sample sequence are determined. Presence of a spreading sequence in the sample sequence is detected by evaluating correlation of reference sub-sequences, of a reference spreading sequence, to the phase differences between samples in a sample sequence. Each of the reference sub-sequences includes fewer chips than the spreading sequence to be detected.

Clear channel assessment

At least one embodiment of a correlator comprising a plurality of correlator taps is configurable to provide synchronization and symbol modulation for a plurality of modulation systems. Among other uses, at least one embodiment of the correlator can provide a coarse symbol timing value. In response to determining the coarse symbol timing value, a receiver can receive a signal. Among other uses, at least one embodiment of the correlator can provide a carrier frequency offset (CFO) estimate. In response to determining the CFO estimate, a receiver can receive a signal.

Configurable correlator for joint timing and frequency synchronization and demodulation

Methods and system for carrier frequency offset (CFO) estimation are described. The method includes determining correlation values between a plurality of samples from a received signal and a plurality of reference signals corresponding to a plurality of CFO candidates. A set of correlation values which exceeds a threshold is determined and a corresponding CFO candidate for each correlation value in the set is selected. A CFO estimate based on an interpolation of selected CFO candidates is then calculated.

Carrier frequency offset estimation for wireless communication

A method is provided, which includes identifying a data transfer rate associated with a wireless communication device. The data transfer rate is identified from a group including a legacy data transfer rate and a plurality of non-legacy data transfer rates. In response to identification of a selected non-legacy data transfer rate, a selected non-legacy modulation scheme is identified, which is associated with the selected non-legacy data transfer rate. Modulation of a data payload is performed according to the selected non-legacy modulation scheme. A non-legacy header structure is formed that includes a non-legacy start-of-frame delimiter (SFD) and an identifier of the selected non-legacy modulation scheme. Modulation of the non-legacy header structure is performed according to the legacy modulation scheme. The modulated non-legacy header structure and the modulated data payload are assembled into a non-legacy frame having a structure that is different from a legacy frame structure specified by the legacy protocol.

A converter unit for an M-order digital modulation to map L input binary sequences of N bits onto M complex values being transmitted through a communication channel, where M=2and L and N are positive integers. The converter unit comprises an input to receive a respective input binary sequence. The converter unit is arranged to individually convert each N bits of the input binary sequence into a real number to obtain a sequence with N real numbers. The converter unit is arranged to execute complex arithmetic operations on the sequence of real numbers and to compute a respective complex value. The respective complex value corresponds to said respective input binary sequence.

Converter unit for an M-order digital modulation and a method thereof

A Viterbi decoding device to decode a signal produced by a convolutional encoder is described. The device may include: an analog-to-digital conversion unit to extract a soft symbol S=(S, S) from the signal, the soft symbol including a first sample value Sand a second sample value S; and a digital processing unit to compute, for each of the N states, a branch metric value of BM_K in dependence on the soft symbol S, K being an index identifying the respective state. The digital processing unit may store the soft symbol S as a complex number S=S+J*Sin a complex number format; and compute a complex branch metric value BM_(K, K')=BM_K+J*BM_K&#x2032; in a complex number format on the basis of the soft symbol S, with K different from K&#x2032;.

Viterbi decoding device and method for decoding a signal produced by a convolutional encoder

A processor unit used to determine a quality indicator, QI, of a communication channel. The processor unit receives received complex symbols at an input, executes a predetermined sequence of transformations on the received complex symbols and computes the error vector magnitude, EVM. The quality indicator, QI, of the communication channel is determined based on the determined error vector magnitude, EVM. Data representing the quality indicator, QI, is outputted at an output of the processor unit. The predetermined sequence of transformations transfers all the received complex symbols to a single predetermined region containing a single target location. The error vector magnitude, EVM, is then calculated as average distance of all the processed received complex symbols in the predetermined single region to the single target location.

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Bucharest, Romania

Mihai-Ionut Stanciu