Abstract: A system and method are disclosed for recovering a current data symbol that is part of a sequence of data symbols from a received signal. Recovering the current data symbol includes determining a set of candidate current data symbols from a set of possible current data symbols wherein the set of candidate current data symbols is a subset of the possible current data symbols that does not include all of the possible current data symbols; determining a set of candidate data symbol sequences wherein each candidate data symbol sequence includes one of the candidate current data symbols; and selecting a recovered data symbol sequence that matches the received signal from the set of candidate data symbol sequences.

Abstract: A communication system such as an OFDM or DMT system has nodes which are allowed to transmit continuously on one or just a few of the system's frequency sub-channels, while the other nodes avoid putting any signal into those sub-channels. Simple low data rate nodes are allowed to use a small number of sub-channels while more complicated nodes use the remainder. A control protocol allows the sharing in time of communications using overlaid and non-overlaid multi-carrier communication techniques. The sharing in time can be done using TDMA, CSMA or polling techniques. In each case, mechanisms are provided for bringing new nodes into the network and for insuring the time alignment of overlaid transmissions. Reliable transmissions are insured through acknowledgement and retransmission facilities.

Abstract: A wireless communication system implements a calibration mode by which individual nodes in the system can determine which other nodes in the system are physically close to them and therefore can be reached with less than full transmitting power. Nodes which can communicate with one another via low power can form a low power constellation (a subset of the complete network) whose nodes can communicate directly with one another using this low power arrangement. The direct communication mode may additionally be used by itself. In another mode, the nodes in the system can communicate amongst themselves via bridges—other, non-access point nodes—to lessen the load on the access point or to accommodate environmental or other conditions. Various ones of these modes may be combined into a predetermined cycle of communication modes to help the physical layer accommodate various types of data handled by the network using beacons or another coordinating technique.

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 disclosed for providing amplification to an input signal. The amplifier comprises an amplification stage configured to provide a gain to an input signal and to produce an amplified output, wherein the amplification stage includes an interface configured to receive a biasing voltage. The amplifier also comprises a peak detection feedback network coupled to the amplification stage configured to adjust the biasing voltage, whereby the peak detection feedback network controls the gain of the amplifier.

Abstract: An embodiment of the present invention provides an automatic gain control system for a wireless receiver that quickly differentiates desired in-band signals from high power out-of-band signals that overlap into the target band. The system measures power before and after passing a received signal through a pair of finite impulse response filters that largely restrict the signal's power to that which is in-band. By comparing the in-band energy of the received signal after filtering to the total signal energy prior to filtering, it is possible to determine whether a new in-band signal has arrived. The presence of this new in-band signal is then verified by a multi-threshold comparison of the normalized self-correlation to verify the presence of a new, desired in-band signal.

Abstract: A method for producing an on-chip signal transforming device. The method includes providing a substrate, and laying a first conductive layer above the substrate, wherein the first conductive layer has a plurality of interleaved inductors. The method then includes laying a second conductive layer above the substrate, wherein the second conductive layer has at least one inductor.

Abstract: A current-steering charge pump circuit and method for switch timing that reduces the amount of switching transients on an output current pulse produced by the charge pump. The current-steering type charge pump circuit includes four control signals, UP, UPB, DN and DNB. In order to produce an UP current pulse output signal, the UPB control signal is first asserted, followed by the UP control signal. After a period of time, which is proportional to the error signal that needs to be applied to a VCO, the UPB signal is first unasserted, followed by the UP signal. Similarly, to produce a DOWN current pulse output signal, a DN control is first asserted, followed by a DNB control signal. After a period of time, which is proportional to the error signal that needs to be applied to a VCO, the DN signal is first unasserted, followed by the DNB signal.

Abstract: In a wireless local area network (WLAN), receiving or transmitting signals having multiple modulation schemes can require the use of multiple clock rates. Providing these multiple clock rates significantly increases silicon area and power consumption, both of which are highly undesirably in a wireless device. A sequencing interpolator can advantageously reduce the number of clock rates by receiving signals at a first rate and outputting signals at a second rate. The sequencing interpolator can include a multiplexer network that selectively determines which coefficients are applied to certain signals. Coefficients are chosen to ensure that an error in a frequency domain is within a given tolerance. The multiplexer network can be controlled by a counter value. At a predetermined count, the interpolated output signal is discarded and the counter is reset.

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: 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: 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. Techniques are provided for performing startup scans for radar, identifying backup channels for a possible channel switch, and efficiently changing channels in the event of radar detection in the operating channel. These techniques advantageously meet current regulatory standards governing DFS while minimizing network startup delays and disruption to users during a radar event.

Abstract: A differential amplifier and a method for amplifying an input signal are disclosed. The differential amplifier comprises an amplification stage configured to amplify an input signal to produce an amplified output, a current source configured to provide a bias current for the amplification stage, and an impedance network connected to the amplification stage and the current source. The impedance network is configured to provide a high common mode impedance within the range of operating frequencies.

Abstract: A system and method are disclosed for providing noise reduction in a sigma delta modulator. Reducing the noise comprises inputting a signal to a plurality of modulator stages; feeding back the signal within at least one of the modulator stages through a feedback loop having a gain wherein the feedback loop provides noise shaping.

Abstract: The present invention provides a planar antenna having a scalable multi-dipole structure for receiving, and transmitting high-frequency signals, including a plurality of opposing layers of conducting strips disposed upon either side of an insulating (dielectric) substrate. The dipoles are bifurcated between sides of a substrate on which the dipoles are disposed. A feed line is balanced to a co-axial cable and feeds one half of the bifurcated dipoles, and an independent feed line is connected to the other half of the bifurcated dipoles. Sets of the dipoles are arranged symmetrically around a center axis of the feed lines. The sets of dipoles are in series with other sets of dipoles. The antenna is ideally suited for operation in the 5.15-5.35 GHz RF band.

Abstract: The present invention provides a planar antenna having a scalable multi-dipole structure for receiving, and transmitting high-frequency signals, including a plurality of opposing layers of conducting strips disposed upon either side of an insulating (dielectric) substrate.

Abstract: The present invention provides a variable gain amplifier with a plurality of gain stages in which each of the gain stages is implemented using a circuit that implements a neutralization approach. This variable gain amplifier provides stable operation characteristics as different gain stages within the variable gain amplifier are turned on and off. This variable gain amplifier also increases linearity across the entire operating range. Additionally, the variable gain amplifier of the present invention provides a constant input impedance through different gain settings. Further, the present invention provides a variable gain amplifier in which each of the various gain stages therein maximize the available voltage swing. Finally, this variable gain amplifier improves common-mode rejection performance and attenuates unwanted harmonics.

Abstract: A dual mode, substantially planar antenna utilizes a dipole or monopole structure for receiving and transmitting high-frequency signals. Layers of conductive strips are disposed on opposite sides of an insulating (dielectric) substrate, such as printed circuit board material. First and second antenna elements are connected via an LC trap, the first antenna element corresponding to a first mode and the combined elements corresponding to a second mode. The LC trap is a single component inductor with parasitic capacitance sufficient to implement the LC trap or a set of patterns printed on the substrate. In one embodiment, the LC trap is constructed with only a single via through the substrate. The antenna is ideally suited for combined 5.5 GHz and 2.4 GHz RF operations.

Abstract: The present invention provides a synthesizer having an efficient lock detect signal generator, an extended range VCO that can operate within any one of a plurality of adjacent characteristic curves defined by a plurality of adjacent regions, and a divide circuit implemented using only a single counter along with a decoder. This allows for a method of operating the synthesizer, methods of establishing or reestablishing a lock condition using the extended range VCO, and a method of designing a plurality of divide circuits which each use the same single counter and each use a different decoder.

Abstract: An embodiment of the present invention provides an automatic gain control system for a wireless receiver that quickly differentiates desired in-band signals from high power out-of-band signals that overlap into the target band. The system measures power before and after passing a received signal through a pair of finite impulse response filters that largely restrict the signal's power to that which is in-band. By comparing the in-band energy of the received signal after filtering to the total signal energy prior to filtering, it is possible to determine whether a new in-band signal has arrived. The presence of this new in-band signal is then verified by a multi-threshold comparison of the normalized self-correlation to verify the presence of a new, desired in-band signal.