Abstract: Methods and systems for calibrating a transmitter with I/Q imbalance and local oscillator feed-through include generating a test tone, frequency up-converting the test tone, monitoring one or more features of the up-converted test tone, and adjusting one or more features of the transmitter in response to the monitoring. The monitoring optionally includes monitoring a beating of the envelope of the up-converted test tone. In an embodiment, a first harmonic of the up-converted test tone is monitored for local oscillator feed-through (LOFT). Alternatively, baseband data inputs to the transmitter are disabled, and LOFT is measured by measuring power at the transmitter output. A second harmonic of the up-converted test tone is monitored for gain and phase imbalances. The adjusting optionally includes adjusting a gain imbalance, adjusting a phase imbalance, and/or adjusting a DC offset. The adjusting optionally includes an iterative refinement process.

Abstract: Methods and systems for calibrating a transmitter with I/Q imbalance and local oscillator feed-through include generating a test tone, frequency up-converting the test tone, monitoring one or more features of the up-converted test tone, and adjusting one or more features of the transmitter in response to the monitoring. The monitoring optionally includes monitoring a beating of the envelope of the up-converted test tone. In an embodiment, a first harmonic of the up-converted test tone is monitored for local oscillator feed-through (LOFT). Alternatively, baseband data inputs to the transmitter are disabled, and LOFT is measured by measuring power at the transmitter output. A second harmonic of the up-converted test tone is monitored for gain and phase imbalances. The adjusting optionally includes adjusting a gain imbalance, adjusting a phase imbalance, and/or adjusting a DC offset. The adjusting optionally includes an iterative refinement process.

Abstract: A receiver in a wireless local area network capable of receiving and processing plurality of frames that are separated by a reduced interframe spacing interval. . Upon receiving a frame, the receiver determines whether the received frame is using Reduced Interframe Spacing intervals. When the received frame includes a RIFS indicator, acknowledgment of the received frame is suppressed, and subsequent frames of the plurality of frames are received at a RIFS interval.

Abstract: Providing wireless transmission, where in a first transmission mode, transmitting a plurality of frames using a first interframe spacing interval. When in a second transmission mode, transmitting the plurality of frames using a second interframe spacing interval, wherein the second interframe spacing is less than the first interframe spacing.

Abstract: A radio frequency receiver for discriminating a modulation type to decode a signal field of an encoded signal in a wireless communication system. The radio frequency (RF) receiver receives an encoded signal having a preamble training sequence associated with a frame, the preamble training sequence including the signal field. The radio frequency receive generates at least a first log-likelihood ratio (LLR) stream and a second LLR stream for each of a plurality of sub-symbols for a predetermined portion of the received encoded signal based upon an m-bit wide modulation reference, wherein m represents the bit width of the modulation reference. The first LLR stream and the second LLR stream each include a plurality of LLR values. The plurality of LLR values of the first LLR stream are summed to produce a first cumulative LLR, and the plurality of LLR values of the second LLR stream are summed to produce a second cumulative LLR.

Abstract: A communication system, including a receiver, is described having a common clock source that drives both carrier frequency (fc) and sampling frequency (fs). The receiver comprises a first signal processing stage for down converting a received data stream to baseband, a demodulation module coupled to the first signal processing stage for demodulating the down-converted data stream, and a second signal processing stage coupled to the demodulation module for decoding the demodulated data stream. Additionally, the receiver includes a carrier frequency offset (CFO) estimation module and a sampling frequency offset (SFO) correction module. The SFO correction module receives an estimated CFO, and then determines an SFO correction based on the estimated CFO, and applies the SFO correction to the received data stream.

Abstract: A receiver includes digital logic for defining a plurality of signal paths for an ingoing digital signal to determine a frame classification. Frames are classified according to a combination of readings of a plurality of correlation block and relative signal (power) strengths. Power detection is specified for frequency bands of interest. The combination of readings and their corresponding pattern may be used to determine whether a frame is being transmitted in a lower bandwidth channel, an upper bandwidth channel or a large bandwidth channel that overlaps the lower and upper bandwidth channels. A transmission type (legacy, mixed mode, Greenfield) may subsequently be determined based upon the identity of the frame channel.

Abstract: A method of controlling power levels on a plurality of transmit streams in a single radio transceiver includes, for each of the plurality of transmit streams, detecting an output power level and sampling the output power level, digitizing the sample output power level, producing the digitized sample to a baseband processor. The baseband processor is operable to perform rate based compensation on the digital sample, to integrate and dump a plurality of digitized samples over a period that exceeds a transmission frame period to produce an average value over a specified number of samples. Thereafter, the processor is operable to convert the integrated plurality of digitized samples to a normalized value and to comparing the normalized value to a target value to generate a power index value to determine an output power level with rate based compensation.

Abstract: A transceiver device for processing a frame in a wireless local area network, where the frame is one of several frame formats, which include a high throughput frame format. The transceiver device receives a frame having a training sequence, a signal field and a data payload, and processes the training sequence to detect which signal field length of a plurality of signal field lengths was used in the received frame. With the signal field length, the device processes the signal field based upon the detected signal field length to retrieve the data payload processing information.

Abstract: Various aspects of a method for and system for multiple input multiple output (MIMO) channel estimation are presented. Aspects of a method for computing channel estimates in a radio frequency (RF) communications system may comprise decomposing a direct matrix computation into a plurality of constituent matrices, and jointly computing a plurality of channel estimates for a corresponding plurality of channel estimate streams received via a plurality of RF channels based on at least a portion of the plurality of constituent matrices. Aspects of a system for computing channel estimates in an RF communications system may comprise a receiver that decomposes a direct matrix computation into a plurality of constituent matrices, and jointly computes a plurality of channel estimates for a corresponding plurality of channel estimate streams received via a plurality of RF channels based on at least a portion of the plurality of constituent matrices.

Abstract: Frame processing for a wireless communication system. The frame processing includes detecting reception of a frame based on a portion of a preamble of a frame, wherein the frame includes a preamble and a data payload. With detecting the reception of a frame, determining a frame type of a plurality of frame types from at least the portion of the preamble. Processing a remaining portion of the preamble in accordance with the frame type to determine payload processing parameters, and processing the data payload based on the payload processing parameters.

Abstract: Methods and systems to calibrating a transmitter for I/Q imbalance and local oscillator feed-through include generating a test tone, frequency up-converting the test tone, monitoring one or more features of the up-converted test tone, and adjusting one or more features of the transmitter in response to the monitoring. The monitoring optionally includes monitoring a beating of the envelope of the up-converted test tone. In an embodiment, a first harmonic of the up-converted test tone is monitored for local oscillator feed-through (LOFT). Alternatively, baseband data inputs to the transmitter are disabled, and LOFT is measured by measuring power at the transmitter output. A second harmonic of the up-converted test tone is monitored for gain and phase imbalances. The adjusting optionally includes adjusting a gain imbalance, adjusting a phase imbalance, and/or adjusting DC offsets. The adjusting optionally includes an iterative refinement process.

Abstract: A calibration device for use in a radio receiver enables receiver self-calibration and self-correction of inbound RF signals. The calibration device includes an estimation module for receiving a sample digital packet and calculating imbalance parameters as a function of a portion of the sample digital packet. The calibration device further includes a correction module for applying the imbalance parameters to a received digital packet of an inbound RF signal to produce a corrected digital packet. The received digital packet may be a portion of the sample digital packet, the complete sample digital packet or a new packet.

Abstract: Angle estimation for modulated signal. A novel compensation technique is presented by which angle estimation may be performed for a modulated signal. More specifically, the angle between a constellation corresponding to a received signal and a constellation corresponding to a received signal may be very efficiently estimated using any one of the possible embodiments corresponding to various aspects of the invention. After this angle has been estimated, the received signal or the expected constellation may be rotated (or de-rotated) to compensate for this angular difference. In doing so, better estimates of the information bits that are demodulated and decoded from the received signal may be made.

Abstract: Multiple-input-multiple-output (MIMO) timing recovery. A novel approach is presented to perform timing recovery when processing the multiple received signals within a MIMO communication device. This may be implemented for a singular received signal, or a plurality of received signal streams. In addition, this timing recovery may be performed in conjunction with carrier detection to provide more robust performance. Alternatively, indicia and/or signals corresponding to carrier detection of these signals may be provided to timing recovery functionality from carrier detection functionality external to the timing recovery functionality. Certain processing and analysis is performed on a modified correlation function that is generated using samples of moving windows that pass over symbols of a packet.

Abstract: Carrier detection applicable for SISO, MIMO, MISO, and SIMO communications. A novel approach is presented to perform carrier detection for a signal found in any of a wide variety of communication systems including single-input-multiple-output (SISO), multiple-input-multiple-output (MIMO), multiple-input-single-output (MISO) single-input-multiple-output (SIMO), communication systems. This novel approach to performing carrier detection is more robust than those approaches existent in the art. By employing normalization with respect to power in determined a modified correlation function, there is less susceptibility to false detects. Also, this approach is quite robust to any circuitry DC offsets that may undesirably exist within a communication device that undergoes operational changes due to a variety of factors including environmental perturbations and/or changes in processing circuitry within the communication device (e.g., changes in gain control).

Abstract: An integrated circuit radio transceiver and method therefor comprises a receiver front end that further includes a plurality of in-phase and quadrature phase receive processing block operable at first and second frequency bands wherein each of the receive processing blocks defines an ingoing signal path and further includes a plurality of filtering and amplification blocks disposed within the corresponding ingoing signal path, a plurality of RSSI blocks coupled to receive an ingoing analog signal from a corresponding plurality of nodes disposed throughout the ingoing signal path, each of the plurality of received signal strength indicator blocks producing a signal strength indication, and wherein a baseband processor is operable to receive a selected signal strength indication and to produce at least one gain setting to at least one amplification block within the in-phase or quadrature phase receive processing blocks.

Abstract: A multi-protocol wireless communication baseband transceiver includes a baseband transmit processing module and a baseband receive processing module. The baseband transmit processing module includes an encoding module, an interleaving module, a plurality of symbol mapping modules, a plurality of domain conversion modules, a plurality of cyclic prefix modules, a plurality of compensation modules, and a control module that is operably coupled to produce preamble set up information and payload set up information based on a mode of a plurality of protocol modes.

Abstract: A method is described for correcting sampling frequency offset (SFO) of a data packet in a communications system where carrier frequency (fc) and sampling frequency (fs) are driven by a common clock source. The method comprises, for each lth symbol in the data packet, estimating carrier frequency offset (CFO) in a received data packet. From the CFO estimate, an SFO estimate is derived, wherein the SFO is approximately equal to fs multiplied by said CFO estimate, and divided by fc. An SFO phase correction is generated according to the SFO estimate for each kth tone in a data stream. The SFO phase correction is then applied to each received data stream.

Abstract: A method is disclosed for correcting carrier frequency offset (CFO) in a received data packet that includes one or more M data streams. The data packet has a payload portion preceded by a preamble portion, the payload portion having a plurality of data symbols (L) each of which include a plurality of data tones (K). The method comprises, making a per-stream preamble CFO estimate for each data stream by correlating repeated preamble portions that precede the data packet. The per-stream preamble CFO estimates are weighted and averaged to obtain a single preamble CFO estimate. Any CFO in each received data stream is then corrected according to the preamble CFO estimate. Additionally, for an lth data symbol in a data packet, a per-tone CFO estimate is derived and successively averaged over frequency (tones), time (symbols) and space (data steams) to derive data CFO estimate pdata. Any CFO in each received data stream may be corrected according to the data CFO estimate, and/or the preamble CFO estimate.