Abstract: Techniques to avoid interference with a frequency hopping signal that are of a periodic or quasi-periodic nature that may operate in the same frequency band and proximity with other devices. For example, the frequency hopping signals may be transmitted by Bluetooth devices operating in the same frequency band as IEEE 802.11 WLAN devices. When a frequency hopping interfering signal is detected, sufficient knowledge of the frequency hopping sequence is derived without obtaining state of a frequency hop sequence from information carried in the frequency hopping signal. This knowledge is used to predict or determine when future transmissions of the frequency hopping signal will be present in a particular frequency channel of concern.

Abstract: Techniques for location tracking of devices having both wireless WAN and wireless LAN capability. A device with this dual communication capability may be triggered to initiate a wireless LAN location procedure in response to receiving a wireless WAN signal. The request for initiating the location process may be a user of the device itself, or any third party desiring knowledge about the location of the device. This process exploits the advantages of the wireless LAN location capabilities to use the wireless LAN link for accurate in-building location. Any location technique useful in a wireless LAN environment may be employed. The system and method are useful to locate any individual or object that is carrying or is tagged with device having wireless WAN and wireless LAN connectivity.

Abstract: Systems and methods to enable different types of radio communication devices to communicate using a common language in order to enable the devices to regulate their use of the spectrum. Each device participating in the ad hoc control channel (ACC) protocol transmits information using a common signal format that each of the other participant devices is capable of recognizing, in order to share information about how it uses the radio frequency band. Each device receives the information transmitted by other participant devices and based on that information, controls one or more of its operational parameters that impact usage of the radio frequency band. The ACC protocol enables devices of the same or different type to harmonize (instead of alienate) themselves with each other by allowing them to communicate about their usage of the radio frequency band using a common signaling framework.

Abstract: A spatial signal processing system and method are provided to optimize the received signal-to-noise ratio (SNR) at a first radio communication device based on the transmit filter at another radio communication device. Using an estimate of the channel derived from a signal received at one device from another device, an iterative process is provided to determine complex weights for one or more tapped delay-line transmit filters at each of two communication devices that optimize the received SNR.

Abstract: A technique to share a local oscillator signal between two radio frequency integrated circuits (RFICs). The local oscillator signal generated internally by one RFIC is ported to the other RFIC for use in transmit and/or receive operation. The local oscillator signal that is ported may be an RF local oscillator signal. Each RFIC may include a bi-directional port circuit that can be operated to make the RFIC a master, slave or may be totally disabled to disable the porting feature. This is particularly useful in RFICs that are used to communicate using MIMO radio algorithms which rely for optimum performance on phase and frequency coherency among a plurality of transmitters and a plurality of receivers.

Abstract: Systems and methods for optimizing the efficiency of each of a plurality of power amplifiers that amplify a corresponding one of a plurality of radio frequency signals for transmission by a corresponding one of a plurality of antennas. Using transmit beamforming, the power of each amplified signal output by the power amplifiers may not be the same for all the power amplifiers, and may vary with changes in the communication channel between the transmitting device and receiving device. Each of the plurality of power amplifiers is controlled to operate with one or more operating parameters that optimize the efficiency for an output power level of corresponding ones of the radio frequency signals. By adjusting one or more operating parameters of each power amplifier according to changing requirements (e.g., the destination device and channel conditions), the efficiency of each power amplifier can be optimized.

Abstract: Methods to optimize range of multicast signal communication in wireless communication applications that use range-enhanced techniques for directed signal communication. A multicast signal may be sent multiple times through each of a plurality of independent omnidirectional transmit antennas of a communication device to a plurality of other communication devices to improve packet error rate (PER) at a given range (i.e., SNR). More generally, the multicast message can be transmitted up to N times using up to N times using any set of N complex linearly independent N-dimensional transmit weight vectors v1, . . . , vN associated with N plurality of transmit antennas that meets the power constraint ?vi?2=1, i=0, . . . ,N?1, where the vector vi is used for the ith transmission of the multicast signal.

Abstract: A system and method for classifying signals occurring in a frequency band. One or more characteristics of one or more signals in the frequency band are detected using any suitable technology, such as a device that can generate characteristics of signal pulses detected in the frequency band. Data pertaining to the signal pulses is accumulated over time. The accumulated signal data is compared against reference data associated with known signals to classify the one or more signals in the frequency band based on the comparison. The accumulated data may include one or more characteristics selected from the group consisting of: pulse center frequency, pulse bandwidth, pulse duration, time between pulses and number of different active pulses, and wherein the reference data associated with each of a plurality of known signals comprises one or more characteristics selected from the group consisting of: pulse center frequency, pulse bandwidth, pulse duration and time between pulses.

Abstract: A signal interfacing technique for connecting signals between a signal processing device and a radio integrated circuit (IC) involving multiplexing two or more signals on a connection pin between the radio IC and a signal processing device. According to one technique, transmit and receive signals are multiplexed such that during a transmit mode a transmit signal is coupled on the connection pin from the signal processing device to the radio IC, and during a receive mode a receive signal is coupled from the radio IC on the connection pin to the signal processing device. According to another technique, in-phase (I) and quadrature (Q) signals are multiplexed on a connection pin during both transmit and receive modes.

Abstract: Several techniques are provided for use by wireless devices to avoid interference with signals that are of a periodic or quasi-periodic nature that may operate in the same frequency band and proximity. In some cases, the periodic signals are detected and their timing is determined so as to predict when a next interfering event will occur. Devices that are affected by the periodic signal (such as an affected device with information to be transmitted or devices that have information to be transmitted to the affected device) are controlled to prevent transmissions during the interfering intervals. In addition, a process is provided to dynamically fragment a transmit frame of information to transmit part of the information before the interfering interval and the remainder of the information after the interfering interval, rather than waiting to transmit the entire frame until after the interfering interval.

Abstract: An equal gain composite beamforming technique which constrains that the power of the signal output by each antenna is the same, and is equal to the total power of the transmit signal divided by the number N of transmit antennas from which the signal is to be transmitted. By reducing output power requirements for each power amplifier, the silicon area of the power amplifiers are reduced by as much as N times (where N is equal to the number of transmit antennas) relative to a non-equal gain CBF.

Abstract: Techniques to avoid interference with a frequency hopping signal that are of a periodic or quasi-periodic nature that may operate in the same frequency band and proximity with other devices. For example, the frequency hopping signals may be transmitted by Bluetooth devices operating in the same frequency band as IEEE 802.11 WLAN devices. When a frequency hopping interfering signal is detected, sufficient knowledge of the frequency hopping sequence is derived without obtaining state of a frequency hop sequence from information carried in the frequency hopping signal. This knowledge is used to predict or determine when future transmissions of the frequency hopping signal will be present in a particular frequency channel of concern.

Abstract: A spatial signal processing system and method are provided to optimize the received signal-to-noise ratio (SNR) at a first radio communication device based on the transmit filter at another radio communication device. Using an estimate of the channel derived from a signal received at one device from another device, an iterative process is provided to determine complex weights for one or more tapped delay-line transmit filters at each of two communication devices that optimize the received SNR.

Abstract: A MIMO radio transceiver to support processing of multiple signals for simultaneous transmission via corresponding ones of a plurality of antennas and to support receive processing of multiple signals detected by corresponding ones of the plurality of antennas. The radio transceiver provides, on a single semiconductor integrated circuit, a receiver circuit or path for each of a plurality of antennas and a transmit circuit or path for each of the plurality of antennas. Each receiver circuit downconverts the RF signal detected by its associated antenna to a baseband signal. Similarly, each transmit path upconverts a baseband signal to be transmitted by an assigned antenna.

Abstract: A MIMO radio transceiver to support processing of multiple signals for simultaneous transmission via corresponding ones of a plurality of antennas and to support receive processing of multiple signals detected by corresponding ones of the plurality of antennas. The radio transceiver provides, on a single semiconductor integrated circuit, a receiver circuit or path for each of a plurality of antennas and a transmit circuit or path for each of the plurality of antennas. Each receiver circuit downconverts the RF signal detected by its associated antenna to a baseband signal. Similarly, each transmit path upconverts a baseband signal to be transmitted by an assigned antenna.

Abstract: An equal gain composite beamforming technique which constrains that the power of the signal output by each antenna is the same, and is equal to the total power of the transmit signal divided by the number N of transmit antennas from which the signal is to be transmitted. By reducing output power requirements for each power amplifier, the silicon area of the power amplifiers are reduced by as much as N times (where N is equal to the number of transmit antennas) relative to a non-equal gain CBF.

Abstract: A spectrum analysis engine (SAGE) that comprises a spectrum analyzer component, a signal detector component, a universal signal synchronizer component and a snapshot buffer component. The spectrum analyzer component generates data representing a real-time spectrogram of a bandwidth of radio frequency (RF) spectrum. The signal detector detects signal pulses in the frequency band and outputs pulse event information entries output, which include the start time, duration, power, center frequency and bandwidth of each detected pulse. The signal detector also provides pulse trigger outputs which may be used to enable/disable the collection of information by the spectrum analyzer and the snapshot buffer components. The snapshot buffer collects a set of raw digital signal samples useful for signal classification and other purposes. The universal signal synchronizer synchronizes to periodic signal sources, useful for instituting schemes to avoid interference with those signals.

Abstract: A VCO having an automatic amplitude control circuit In the form of a sensing amplifier provided in the feedback loop to sense the oscillator amplitude and draw current away only when the positive peak voltage Is above a certain value. In general, any amplifier may be used in the feedback loop that outputs current proportional to a peak positive input (in a non-linear and asymmetric fashion with respect to the changing voltage). In one example, the amplifier in the feedback loop comprises first and second transistors that are set nominally in cut off and behave as class C amplifiers. The advantage of this amplifier transistor configuration is that the amplifier they form has a low load on the LC tank circuit and a high input impedance.

Abstract: A composite beamforming technique is provided wherein a first communication device has a plurality of antennas and the second communication has a plurality of antennas. When the first communication device transmits to the second communication device, the transmit signal is multiplied by a transmit weight vector for transmission by each the plurality of antennas and the transmit signals are received by the plurality of antennas at the second communication device. The second communication device determines the best receive weight vector for the its antennas, and from that vector, derives a suitable transmit weight vector for transmission on the plurality of antennas back to the first communication device. Several techniques are provided to determine the optimum transmit weight vector and receive weight vector for communication between the first and second communication devices so that there is effectively joint or composite beamforming between the communication devices.

Abstract: A VCO having an automatic amplitude control circuit in the form of a sensing amplifier provided in the feedback loop to sense the oscillator amplitude and draw current away only when the positive peak voltage is above a certain value. In general, any amplifier may be used in the feedback loop that outputs current proportional to a peak positive input (in a non-linear and asymmetric fashion with respect to the changing voltage). In one example, the amplifier in the feedback loop comprises first and second transistors that are set nominally in cut off and behave as class C amplifiers. The advantage of this amplifier transistor configuration is that the amplifier they form has a low load on the LC tank circuit and a high input impedance.