Abstract: In order to decrease the temperature sensitivity of an oscillator output, and obtain a frequency of oscillation that remains stable over variations in temperature, two oscillators may be configured with identical comparators and logic circuitry, but having different oscillation frequencies. The different oscillation frequencies may be achieved by configuring each oscillator with a respective resistor divider circuit configured to adjust the reference voltage at the reference input of the respective comparator. The difference between the respective periods of oscillation of the two oscillators may therefore become independent of the comparator delay, and may only depend on temperature sensitivity of the resistor.

Abstract: A VCO comprises an LC tank circuit coupled to a plurality of cross-coupled transistor devices. A first resonance frequency of a waveform output of the VCO is dependent upon the values of a first capacitor and a first inductor of the LC tank. The VCO further comprises a first series LC resonator comprising a second capacitor and a second inductor in parallel to the first capacitor and the first inductor. The values of the second capacitor and second inductor are selected to produce a second resonance frequency that is a third harmonic of the first resonance frequency, thereby increasing a slope of the voltage controlled oscillator output. The increased slope reduces phase noise, which leads to improved signal-to-noise ratio.

Abstract: A complementary metal oxide semiconductor transceiver analog front end circuit includes a combined transmit and receive amplifier block that produces an amplified transmit differential signal and receives a receive differential signal through the same pair of input/output nodes coupled to an external network through an RF choke block. In one embodiment the combined transmit and receive amplifier block includes separate power amplifier and low noise amplifier circuits, while a second embodiment includes a power amplification stage and a combined power amplification/low noise amplification stage. The amplifier circuits may be constructed using a combination of thin oxide core transistors and thick oxide input/output transistors. DC feeds may be selected to power the circuits in response to a transmit/receive control signal. Bias voltages to the amplifier circuits' transistors may also be set in response to the transmit/receive control signal.

Abstract: An apparatus and method are provided for efficiently sharing a single wireless channel and for providing improved power saving. Automatic beacon “sliding” establishes a round-robin contention-free channel schedule among multiple IBSSs. Entering an idle state immediately following communication after a beacon saves power. Further power savings occur when presumptions of pending traffic may be made.

Abstract: Accurate position capability can be quickly provided using a Wireless Local Area Network (WLAN). When associated with a WLAN, a wireless device can quickly determine its relative and/or coordinate position based on information provided by an access point in the WLAN. Before a wireless device disassociates with the access point, the WLAN can periodically provide time, location, and decoded GPS data to the wireless device. In this manner, the wireless device can significantly reduce the time to acquire the necessary GPS satellite data (i.e. on the order of seconds instead of minutes) to determine its coordinate position.

Abstract: An AGC control unit coordinates AGC gain changes between individual receive chains included within a MIMO receiver block. Coordinated AGC gain changes reduce time periods of unaligned MIMO data produced by the receive chains. Reducing the unaligned data periods advantageously increases the time that the output data may be combined to improve overall performance of the receiver block. Coordinated AGC control also enables a faster response to saturated signals since the gain of multiple receive chains may be changed contemporaneously.

Abstract: A method and corresponding system for operating in a network in which stations communicate over a shared medium are presented. The shared medium has at least one varying channel characteristic that varies approximately periodically. The method includes providing repeated beacon transmissions from a coordinator station for coordinating transmissions among a plurality of the stations, wherein at least some beacon transmissions are synchronized to the varying channel characteristic; and transmitting from a first station to at least one receiving station during a time slot determined based on at least one of the beacon transmissions received by the first station from the coordinator station.

Abstract: A method of operating in a network in which a plurality of stations communicate over a shared medium, comprising providing a physical layer (e.g., PHY) for handling physical communication over the shared medium; providing a high level layer (e.g., PAL) that receives data from the station and supplies high level data units (e.g., MSDUs) for transmission over the medium; providing a MAC layer that receives the high level data units from the high level layer and supplies low level data units (e.g., MPDUs) to the physical layer; at the MAC layer, encapsulating content from a plurality of the high level data units; dividing the encapsulated content into a plurality of pieces (e.g., segments) with each piece capable of being independently retransmitted; and supplying low level data units containing one or more of the plurality of pieces.

Abstract: A system and method for wirelessly transmitting both real-time data streams and remote control signals is described. A first transceiver can be used for detecting remote control signals associated with an end device (e.g. a television), transforming these remote control signals into wireless signals, and transmitting the wireless signals. A second transceiver can be used for receiving the wireless signals and transforming the wireless signals into the recreated remote control signals. The recreated remote control signals can then be sent to a source device (e.g. a DVD player). Because wireless signals are used (instead of infrared (IR) signals, for example), the source device can be outside the line of sight of the end device and still respond to the remote control signals.

Abstract: Electrostatic discharge (ESD) can affect the operation of and even damage an unprotected integrated circuit. Conventional ESD protection circuits may not be able to protect the integrated circuit if the voltage at the output of the integrated circuit swings with large amplitude. In some embodiments, an ESD protection circuit comprising switching circuitry that provides a low AC impedance path to ground can prevent improper triggering of the ESD protection circuit during normal operation of the integrated circuit, while ensuring that the ESD protection circuit device reliability is not compromised.

Abstract: A multiple-input multiple-output (MIMO) system can transmit on multiple antennas simultaneously and receive on multiple antennas simultaneously. Unfortunately, because a legacy 802.11a/g device is not able to decode multiple data streams, such a legacy device may “stomp” on a MIMO packet by transmitting before the transmission of the MIMO packet is complete. Therefore, MIMO systems and methods are provided herein to allow legacy devices to decode the length of a MIMO packet and to restrain from transmitting during that period. These MIMO systems and methods are optimized for efficient transmission of MIMO packets.

Abstract: Transient distortion is compensated for by multiplying an exponentially-decaying phase shift onto the distorted waveform. The exponentially decaying phase shift waveform is patterned after the transient which typically takes the form of an exponential and occurs upon introduction of power to a circuit or circuit component. A digital circuit produces an appropriate exponentially-decaying waveform which is used as the input for a look up table whose output is a complex sinusoidal waveform capable of compensating for the distortion. The complex sinusoid is multiplied onto the transmitted waveform. The decaying exponential is biased so that it crosses a threshold at which point the compensating circuitry is turned off.

Abstract: A method of processing a signal in a wireless network including multiple chains is provided. This method can include receiving the signal in a receiver and, for each chain, performing a Barker correlation on the signal to generate a Barker correlated signal. At this point, an autocorrelation can be performed on the Barker correlated signal to generate an autocorrelated signal. The autocorrelated signals from the multiple chains can be summed to generate a summed output. Additional processing, e.g. at least one of CCK weak signal detection, peak selection in a rake receiver, frequency estimation, and differential decoding, can then be performed based on the summed output.

Abstract: A station to serve as a proxy for responding to a multicast message is selected using dynamically maintained information about other stations communicatively coupled to a shared communications network. The dynamically maintained information is used to select a station having a high probability of replying to the multicast message. Network performance may be further improved by re-selecting proxies when a multicast frame fails to acknowledged.

Abstract: A method and apparatus in a multiple sub-carrier digital communication receiver that estimates a communication channel. A second set of channel estimates are generated based on a Wiener filter interpolation of a first set of channel estimates. Pre-determined transmit pilot symbols may be used to generate the first set of channel estimates in an OFDM communication system. The coefficients of the Wiener interpolation filter are based on a channel impulse response estimate that includes two or more narrow regions of non-zero amplitude separated by one or more wide regions of essentially zero amplitude. The Wiener interpolation filter coefficients are also based on a Doppler frequency estimate. The Doppler frequency estimate may be determined from the first set of channel estimates, while the Wiener interpolation filter coefficients may be generated from a pre-determined set of channel impulse responses.

Abstract: A method to equalize multiple-input multiple-output (MIMO) signals assigns a weight to the output of each receive chain in the MIMO system based on a first noise power value in each receive chain. A second noise power value can be computed using a difference between identical symbols from one or more weighted/un-weighted receive chain signals. Notably, the second noise power value includes thermal noise, phase noise, quantization noise, and distortion noise. The weighted outputs of the receive chains and the second noise power estimate may be used in an equalization calculation to recover the input signal.

Abstract: A method for generating a signal is presented. The method includes selecting a first set of carrier frequencies that are integral multiples of a first frequency interval, and selecting a second set of carrier frequencies that are integral multiples of a second frequency interval. The second frequency interval is an integral multiple of the first frequency interval and the second set is a subset of the first set. The method includes, for each of one or more signal carrier frequencies in the second set, selecting a plurality of associated carrier frequencies in the first set including a peak carrier frequency having substantially the same value as the signal carrier frequency, and modulating waveform frequency components at each of the selected plurality of associated carrier frequencies according to the same data value.

Abstract: A selectable frequency source for use in GPS receivers. A device in accordance with one or more embodiments of the present invention comprises at least one reference frequency source, a circuit, coupled to the at least one reference frequency source, and a mixer, coupled to an output of the circuit, for mixing a GPS signal with the output of the circuit, wherein a frequency output of the mixer is changed based on an input to the circuit.

Abstract: An ambient country identifier (ACI) signal can be used to automatically provide location awareness for a WLAN device. If an ACI signal is detected, then the WLAN device can configure itself to comply with channel and power settings for the country having the detected ACI signal. After detection of the ACI signal, the WLAN device can be “locked” to the country having that ACI signal, thereby ensuring legal operation of the WLAN device even after subsequent restarts. If an ACI signal is not detected, then the WLAN device can be configured in a default mode, e.g. an “open mode” in which end users can configure the WLAN device by entering a country of operation or a “common mode” in which the channel and transmit power settings meet global spectrum usage requirements.

Abstract: A receiver for receiving both GPS signals and GLONASS signals is provided. This receiver includes an analog front end (AFE), a GPS digital front end (DFE) and a GLONASS DFE for receiving an output of the AFE, and a dual mode interface (DMI) for receiving outputs of the GPS and GLONASS DFEs. Search engines are provided for receiving outputs of the DMI. Notably, certain front-end components of the AFE are configured to process both the GPS signals and the GLONASS signals.