Abstract: A wireless transmitter includes a radio interface and transmitter circuitry. The radio interface includes multiple transmit antennas. The transmitter circuitry is configured to hold multiple steering matrices specifying weights to be applied to one or more spatial streams transmitted via the multiple transmit antennas to a receiver that includes one or more receive antennas, the multiple steering matrices are specified over multiple sub-carriers, to calculate smoothed weights, by applying to the weights of the steering matrices phase-only corrections that reduce phase variations among the weights of the steering matrices over the sub-carriers, and to transmit to the receiver beam-formed transmissions of the one or more spatial streams over the sub-carriers, by applying to the spatial streams the smoothed weights in the respective sub-carriers.

Abstract: A wireless transmitter includes a radio interface and transmitter circuitry. The radio interface includes multiple transmit antennas. The transmitter circuitry is configured to hold multiple steering matrices specifying weights to be applied to one or more spatial streams transmitted via the multiple transmit antennas to a receiver that includes one or more receive antennas, the multiple steering matrices are specified over multiple sub-carriers, to calculate smoothed weights, by applying to the weights of the steering matrices phase-only corrections that reduce phase variations among the weights of the steering matrices over the sub-carriers, and to transmit to the receiver beam-formed transmissions of the one or more spatial streams over the sub-carriers, by applying to the spatial streams the smoothed weights in the respective sub-carriers.

Abstract: A wireless access point (AP) includes multiple transmit antennas and circuitry. The circuitry is configured to transmit multiple sounding frames to a receiver that includes one or more receive antennas, the sounding frames are transmitted via respective different partial subgroups of the transmit antennas, to receive from the receiver feedback information that specifies for each of the sounding frames a respective channel between the transmit antennas in the respective partial subgroup and the receive antennas, and, to determine a steering matrix based on the feedback information, and transmit to at least the receiver via at least some of the transmit antennas using the steering matrix.

Abstract: A wireless transceiver contains a receiver and a transmitter. The receiver is operable in single-input single-output (SISO) mode as well as multiple-input multiple-output (MIMO) mode, and contains a pair of in-phase and quadrature signal processing chains and a baseband processor. In SISO mode, each of the processing chains in the pair is connected to receive a same modulated signal as input, and generates respective baseband outputs. The baseband processor processes the baseband outputs to demodulate the modulated signal. In MIMO mode, the signal processing chains in the pair receive different modulated signals and generate corresponding down-converted signals. The baseband processor processes the down-converted signals to demodulate the respective modulated signals received by the receiver. Corresponding techniques to provide MIMO in addition to SISO capabilities are implemented in the transmitter also.

Abstract: An apparatus for wireless communication includes a plurality of antennas, a master baseband integrated circuit (BBIC) and a slave BBIC. The antennas are configured to communicate a Multiple-Input Multiple-Output (MIMO) signal. The master BBIC is configured to process a first component of the MIMO signal that is communicated via a first subset of the antennas. The slave BBIC is configured to process a second component of the MIMO signal that is communicated via a second subset of the antennas. The master BBIC is further configured to control the slave BBIC so as to jointly communicate the MIMO signal, based on the first and second components, via the entire plurality of the antennas.

Abstract: A wireless access point (AP) includes multiple transmit antennas and circuitry. The circuitry is configured to transmit multiple sounding frames to a receiver that includes one or more receive antennas, the sounding frames are transmitted via respective different partial subgroups of the transmit antennas, to receive from the receiver feedback information that specifies for each of the sounding frames a respective channel between the transmit antennas in the respective partial subgroup and the receive antennas, and, to determine a steering matrix based on the feedback information, and transmit to at least the receiver via at least some of the transmit antennas using the steering matrix.

Abstract: An apparatus for wireless communication includes a plurality of antennas, a master baseband integrated circuit (BBIC) and a slave BBIC. The antennas are configured to communicate a Multiple-Input Multiple-Output (MIMO) signal. The master BBIC is configured to process a first component of the MIMO signal that is communicated via a first subset of the antennas. The slave BBIC is configured to process a second component of the MIMO signal that is communicated via a second subset of the antennas. The master BBIC is further configured to control the slave BBIC so as to jointly communicate the MIMO signal, based on the first and second components, via the entire plurality of the antennas.

Abstract: A novel and useful apparatus for and method of packet detection and carrier frequency offset estimation. The packet detection mechanism is robust to channels and sustains reasonable miss-detect (and false alarm) rates at low SNR values. The mechanism uses a modified combined cross correlation and delay and correlate scheme. A delay and correlate scheme is used in order to handle the effects of multipath while swapping integration and multiplication to increase cross-correlation factors resulting in improved sensitivity in low SNR conditions. Correlation is divided into multiple chains to generate a plurality of partial correlations to observe short patterns in the spread sequence resulting in improved performance in long multipath channels.

Abstract: A novel and useful apparatus for and method of distributed coexistence for mitigating interference in a single chip radio and/or a multi-radio (i.e. multi-transceiver) communications device. The invention enables coexistence ‘friendly’ radio IPs having frequency agility in that they are capable of shifting their clock frequencies thereby avoiding frequency bands of potential victim radios. Frequency agility on the aggressor radio side (rather than by mitigating the effect of interference on the victim radio side) prevents harmonics from the aggressor's clock scheme from falling in the operating frequency band of the victim radio, and in turn causing degradation to its performance. Each aggressor radio, based on information received from other radios, configures the root clock frequency of its RX and/or TX chain clock generation circuits.

Abstract: A novel and useful range extension and in-band noise mitigation mechanism that uses conventional CRC error detection codes to correct single and multiple bit errors in packets received over a communications link. The CRC error correction mechanism of the invention is particularly suitable for use with communication protocols with weak error correction capabilities. The mechanism uses the linearity property of the CRC calculation to detect the existence of errors in the received packet. The entire received packet is searched for single bit errors and are corrected in a single cycle. If no single bit errors are found, the mechanism then searches for multiple bit errors. Packet retransmissions are used to detect and mark the location of multiple bit errors. Multiple bit errors are corrected by trying a plurality of hypotheses of single bit error corrections. Each hypotheses pattern is investigated to find matching CRC patterns for correction using the single bit, single cycle CRC error correction method.

Abstract: A novel and useful apparatus for and method of closed loop IQ calibration for use in a transmitter. The IQ calibration mechanism functions to provide calibration of IQ imbalance in the presence of real world RF impairments. An iterative process is used to update the gain and phase mismatch values whereby the metrics are calculated in a differential manner without the need for calculation absolute imbalance values. At each iteration, updating the gain and phase mismatch estimate requires only the direction of the correction to be determined. The direction of the correction is calculated using only the differences between output power measurements. The updated gain and phase mismatch estimates are used to update an IQ correction matrix. This process is repeated until a desired stopping criterion is reached. Gear shifting is used to ensure quick convergence of the algorithm while providing the ability to achieve any desired level of accuracy.

Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. A synthesizer provides 4/3 the desired frequency fRF. This frequency is divided by two to obtain in-phase and quadrature square waves at ? fRF. The in-phase signal is divided by two again to obtain in-phase and quadrature square waves at ? fRF. The signals are then logically combined using XOR operations to obtain I and Q branch signals containing spectral spurs. Since the spurs are located in non-disturbing bands, they can be filtered out resulting in the desired output signal.

Abstract: A novel and useful apparatus for and method of nonlinear adaptive phase domain equalization for multilevel phase coded demodulators. The invention improves the immunity of phase-modulated signals (PSK) to intersymbol interference (ISI) such as caused by transmitter or receiver impairments, frequency selective channel response filtering, timing offset or carrier frequency offset. The invention uses phase domain signals (r, ?) rather than the classical Cartesian quadrature components (I, Q) and employs a nonlinear adaptive equalizer on the phase domain signal. This results in significantly improved ISI performance which simplifies the design of a digital receiver.

Abstract: A system and method of flexible channel allocation in an ultra wideband frequency hopping communication system is disclosed. In one embodiment, a method includes communicating radio signals through rapidly switching among a band group 6 according to a hopping pattern. The method also includes scanning the ultra wideband spectra to determine the band group 6 based on the hopping pattern of the radio signals. In another embodiment, a method includes scanning ultra wideband spectra to eliminate any frequency band of the ultra wideband spectra from a list of available frequency bands when the any frequency band is currently used, selecting a band group in combination of two or more frequency bands to communicate radio signals with an optimal transmission power and/or maximum range, and communicating the radio signals through rapidly switching among the band group.

Abstract: A wireless transceiver contains a receiver and a transmitter. The receiver is operable in single-input single-output (SISO) mode as well as multiple-input multiple-output (MIMO) mode, and contains a pair of in-phase and quadrature signal processing chains and a baseband processor. In SISO mode, each of the processing chains in the pair is connected to receive a same modulated signal as input, and generates respective baseband outputs. The baseband processor processes the baseband outputs to demodulate the modulated signal. In MIMO mode, the signal processing chains in the pair receive different modulated signals and generate corresponding down-converted signals. The baseband processor processes the down-converted signals to demodulate the respective modulated signals received by the receiver. Corresponding techniques to provide MIMO in addition to SISO capabilities are implemented in the transmitter also.

Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The signal is input to a synthesizer timed to a rational multiplier of the RF frequency fRF. The signal is then divided to generate a plurality of phases of the divided signal. A plurality of combination signals are generated which are then multiplied by a set of weights and summed to cancel out some undersired products. The result is filtered to generate the LO output signal.

Abstract: A novel system and method for correcting the residual phase offset between a recovered pilot signal and the received stereo signal. The invention uses a Costas loop as an auxiliary loop in addition to the pilot recovery phase locked loop (PLL) to lock onto the stereo component itself. This auxiliary loop functions to generate a pilot to stereo component phase correction signal that is added to the stereo carrier phase The resultant phase is used to generate the recovered pilot carrier used to demodulate the stereo MPX signal. The Costas loop is activated together with the main pilot recovery PLL that locks onto the pilot tone in the demodulated MPX signal. The auxiliary Costas loop is operative to track and determine a residual phase error of up to several degrees.

Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The input signal is fed to a synthesizer timed to a rational multiplier of the RF frequency L/N fRF. The clock signal generated is divided by a factor Q to form 2Q phases of the clock at a frequency of L(N*Q)fRF, wherein each phase undergoes division by L. The phase signals are input to a pulse generator which outputs a plurality of pulses. The pulses are input to a selector which selects which signal to output at any point in time. By controlling the selector, the output clock is generated as a TDM based signal. Any spurs are removed by an optional filter.

Abstract: A novel and useful apparatus for and method of distributed coexistence for mitigating interference in a single chip radio and/or a multi-radio (i.e. multi-transceiver) communications device. The invention enables coexistence ‘friendly’ radio IPs having frequency agility in that they are capable of shifting their clock frequencies thereby avoiding frequency bands of potential victim radios. Frequency agility on the aggressor radio side (rather than by mitigating the effect of interference on the victim radio side) prevents harmonics from the aggressor's clock scheme from falling in the operating frequency band of the victim radio, and in turn causing degradation to its performance. Each aggressor radio, based on information received from other radios, configures the root clock frequency of its RX and/or TX chain clock generation circuits.

Abstract: A novel and useful apparatus for and method of closed loop IQ calibration for use in a transmitter. The IQ calibration mechanism functions to provide calibration of IQ imbalance in the presence of real world RF impairments. An iterative process is used to update the gain and phase mismatch values whereby the metrics are calculated in a differential manner without the need for calculation absolute imbalance values. At each iteration, updating the gain and phase mismatch estimate requires only the direction of the correction to be determined. The direction of the correction is calculated using only the differences between output power measurements. The updated gain and phase mismatch estimates are used to update an IQ correction matrix. This process is repeated until a desired stopping criterion is reached. Gear shifting is used to ensure quick convergence of the algorithm while providing the ability to achieve any desired level of accuracy.