Abstract: Current OFDM systems use a limited number of symbols and/or sub-channels to provide approximations for channel estimations and pilot tracking, i.e. phase estimations. For example, two training symbols in the preamble of a data packet are used to provide channel estimation. Four of the fifty-four sub-channels are reserved for providing phase estimation. However, noise and other imperfections can cause errors in both of these estimations, thereby degrading system performance. Advantageously, decision feedback mechanisms can be provided to significantly improve channel estimation and pilot tracking in OFDM systems. The decision feedback mechanisms can use data symbols in the data packet to improve channel estimation as well as data sub-channels to improve pilot tracking.

Abstract: A method and system for reducing the DC offset in a receiver in the presence of carrier frequency offset between the transmitter and the receiver. The present invention utilizes the knowledge of the carrier frequency offset to determine the phase difference between two (or more) snapshots of the same transmitted symbol. The receiver DC offset is solved for using a linear system solver which can be implemented outside the analog domain. The DC offset may be tracked in order to maintain a constant adjust of the DC offset, which in combination with the above DC offset estimation technique implements a complete solution for the DC offset cancellation problem.

Abstract: The present invention provides a method of and an apparatus for changing the gain of a receive path amplifier during the middle of a packet transmission, and particularly changing the gain during a guard interval between a symbol with encoding bits disposed therein and a subsequent data symbol encoded in a manner corresponding to the encoding bits.

Abstract: A Hardware MAC (Media Access Control) unit implements time-critical functions according the 802.11 standard for telecommunications, thereby enhancing system performance. The MAC layer includes three sub-layers: MLME (MAC Sublayer Management Entity), which connects the MAC unit with the host CPU, FTM (Frame Transition Manager), which connects the MAC unit with the network, and FLPM (Frame Level Protocol Manager), which internally connects the MLME sub-layer with the FTM sub-layer. In particular, the FLPM manager includes time-critical and non-time-critical functions that are customarily implemented in software on the MAC by a MAC CPU (Central Processing Unit). The hardware MAC implements time-critical FLPM functions in hardware on the MAC and implements non-time-critical FLPM functions in software on the host CPU so that requirements for processing software on the MAC preferably may be altogether eliminated or alternatively may be substantially reduced.

Abstract: A high-speed wireless link communicates data between a central storage system and a mobile remote system. The wireless link further communicates data between two mobile remote systems. Both the central storage system and the mobile remote system include a central processor, a memory, a transceiver, and a means for data output. The high-speed wireless link is established between the transceivers. Data are loaded, processed and stored on the central storage system. The data, including musical data in MP3 format, are automatically downloaded at high transmission speeds from the central storage system to the mobile remote system.

Abstract: An antenna switch diversity algorithm, and systems and methods to provide antenna diversity by implementing the algorithm in, for example, an IEEE 802.11a compliant environment, are presented. In accordance with the algorithm, one antenna of at least two antennas is designated as a default antenna at a communications device that sends and receives transmit and receive packets. The default antenna designation is changed depending on long-term and short-term learning processes implemented in, for example, software and hardware. The long-term and short-term learning processes analyze packet transmission and reception results of the antennas. The antenna switch diversity algorithm is applicable to multiple antennas.

Abstract: Radar Pulse detection and radar signal length detection are used to detect and provide information for identifying radar signals. Pulse detection estimates a radar pulse size when it is too short for meaningful measurement. Pulse detection identifies a radar by identification of an in-band pulse without a communication or data packet encoded therein, or a communication error is detected with the in-band pulse. Signal length detection counts the length of a received signal after the received signal exceeds a radar threshold. The count identifies the received signal length upon drop of the power. The signal is identified as a radar when the power drops before a PHY error occurs, or when the power drop occurs after a PHY error and a delay time equivalent to the shortest radar signal. A radar signal is also identified upon a timeout wait for a power drop after a PHY error.

Abstract: A differential circuit layout can advantageously use step symmetry for inductors and mirror symmetry for the rest of the circuit. Interconnect segments can be used to connect the terminals of the inductors to other components in the circuit. These interconnect segments facilitate the transition from the step symmetry of the inductors to the mirror symmetry of the other components. To provide this transition, the terminals of an inductor and its associated interconnect segments are formed on a middle axis of the inductor. This mixed symmetry can advantageously cancel the common-mode magnetic field, reduce the parasitic inductor coupling, and balance parasitic wiring capacitances between the two sides of the differential circuit.

Abstract: A phase selector for selecting a differential output is provided. The phase selector can include two matched transistor circuits. A first transistor circuit can receive a first differential input signal whereas a second transistor circuit can receive a second differential input signal. One of the transistor circuits can be used to dump an output current generated by the first differential input signal to Vdd. The other transistor circuit can be used to steer an output current generated by the second differential input signal to two output lines, thereby providing a differential output signal on the output lines.

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 method of queue management includes: adding entries having a first priority to a first software queue; adding entries having a second priority to a second software queue; reading entries from the first software queue to a physical queue; at a threshold time, flushing entries from the physical queue; after the act of flushing the physical queue, reading entries from the second software queue to the physical queue until a termination criterion is satisfied; after the termination criterion is satisfied, reading entries from the first software queue to the physical queue; and transmitting entries from the physical queue to a network.

Abstract: A frequency synthesizer and a method for frequency synthesis are disclosed. The frequency synthesizer comprises a voltage controlled oscillator for generating an output signal having a synthesized frequency, and a prescaler connected to the VCO for receiving the output signal and providing a feedback signal. The prescaler programmatically selects between an integer divider value and a fractional divider value to divide the synthesized frequency of the output signal.

Abstract: A system and method are described for reducing data transmission collisions in a shared transmission medium. In one embodiment, transmission priorities are set by means of priority-defining transmissions. In another embodiment, statistically equal access is assured by means of unique transmit start time slot pairs wherein the paired start time slots are substantially equally spaced in time from a center start time slot. In yet another embodiment, data transmission traffic analysis is used to set unique transmission start time slots or to select from pools of start time slots associated with classes of data to be transmitted, thus establishing relative preemption priorities. In still another embodiment, transmission begins in statically assigned start time slots that are subsets of an available array of transmission start time slots.

Abstract: A technique for automatically controlling the gain of an amplifier by using a transistor as a voltage controlled variable degeneration resistor. The apparatus and method may be advantageously adapted for use in either voltage-to-current amplifiers or voltage-to-voltage amplifiers, single-ended or differential designs. One benefit of this technique is that, since the bias current is constant, the transistors operate in the correct region (i.e. the transistors are not biased out of the operating region). Additionally, the control mechanism is well-bounded.

Abstract: Radar Pulse detection and radar signal length detection are used to detect and provide information for identifying radar signals. Pulse detection estimates a radar pulse size when it is too short for meaningful measurement. Pulse detection identifies a radar by identification of an in-band pulse without a communication or data packet encoded therein, or a communication error is detected with the in-band pulse. Signal length detection counts the length of a received signal after the received signal exceeds a radar threshold. The count identifies the received signal length upon drop of the power. The signal is identified as a radar when the power drops before a PHY error occurs, or when the power drop occurs after a PHY error and a delay time equivalent to the shortest radar signal. A radar signal is also identified upon a timeout wait for a power drop after a PHY error.

Abstract: Methods of manufacturing an antenna are presented. The antenna is capable of being mounted on a printed circuit board. In accordance with the method, the design dimension of a unitary piece of material are selected according to an operating wavelength. The unitary piece of material is stamped out from a larger section of material according to the design dimensions to form an antenna. The unitary piece of material includes a circular area and a stem area. The circular area has a center and an outer region. The stem area has a first end and a second end. The first end is joined with the outer region. The unitary piece is bendable at the first end and the outer region.

Abstract: Various regulatory domains promulgate standards to define how wireless devices should operate in certain frequency bands. The 5 GHz spectrum is of particular importance to certain regulatory domains because of radar systems also operating in this spectrum. To avoid interference with such radar systems, wireless devices operating in this spectrum should be able to detect radar and quickly vacate any channels currently used by the radar systems. In a channel switching technique, if the new channel is radar-exempt, then normal operation commences on the new channel. If the new channel is non-radar-exempt, then normal operation commences on a temporary radar-exempt channel and an aggregate background scan can be performed on the new channel. If no radars are detected using the aggregate background scan, then operation is switched from the temporary radar-exempt channel to the new channel. This channel switching technique minimizes disruption to users during a radar event.

Abstract: A method and apparatus to wirelessly control network devices is described. In one embodiment, a wireless device is used to control at least one host device using a network. In one aspect, a wireless device receives and determines a response to network control signals received thereto. In another aspect, a wireless device controls a host sleep sequence to allow a network to remotely power a host device between an active and passive state. In one aspect, a wireless device provides one or more network identification responses to signals received from the network. In another aspect, a network provides an alert to a third party such as a network administrator if the network determines a wireless device is absent from the network due to a loss of signal therefrom.

Abstract: An antenna is provided with an electronic component or circuit that has a value corresponding to properties of the antenna. A read mechanism reads the value and sets an operational status of a transceiver based on the value. In one embodiment, electronic component is a resistor having a value that identifies the antenna properties. A table may be used to correlate resistor values to different types of antennas or sets of antenna properties. Alternatively, the circuit can be embodied in a microchip that provides a response to a challenge sent by the read mechanism. The response encodes the properties of the antenna. The encoding scheme includes values from the challenge. Alternatively, the response is a code that is indexed into a table of antenna properties. In one embodiment, the antenna is connectorized.

Abstract: The present invention provides a breakdown resistant transistor structure for amplifying communication signals. This structure includes a first NMOS transistor having a source connected to ground and a first gate for receiving the input radio frequency signal. The first gate is disposed above a first insulator and the first NMOS transistor having a first transconductance and a first breakdown voltage associated therewith. Also included is a second NMOS transistor having a source connected to the drain of the first NMOS transistor, a gate connected to the reference DC voltage, and a drain that provides the output for the amplified radio signal, the load being disposed between the reference DC voltage and the drain of the second NMOS transistor. The second gate is disposed above a second insulator, the second NMOS transistor has a second transconductance and a second breakdown voltage associated therewith, and the second insulator may be thicker than the first insulator.