[MILLER, Karl, A., MASON, David, F.] 20400 Observation Drive Suite 206 Germantown, MD 20876;210 Magnolia Avenue Frederick, MD 21701;P.O. Box 1109 Germantown, MD 20875 Signal classification techniques for classifying signals occurring in a frequency band using a plurality of classifier procedures each dedicated to identify a particular signal or signal type. The classification procedures operate on spectrum activity data that may include pulse event data describing particular types of signal pulses occurring in the frequency band, power versus frequency data for sampling intervals of activity in a frequency band and/or raw analog-to-digital converter samples take of a received signal. The signal classification techniques are useful to identify wireless radio signals or other radio emissions occurring in an unlicensed radio frequency band. On type of classification procedure is a pulse timing template that is compared against accumulated signal pulse data to determine occurrence of a particular signal type. To enhance the pulse timing template signal classifier, techniques are provided to examine the center frequency distribution of signal pulses that match the timing template in order to confirm that certain signal pulses are associated with a particular frequency hopping signal type. This is particularly useful when the accumulated signal pulse data is obtained from a scanning radio receiver that is tuned to different portions/channels of the frequency band in which the frequency hopping signal is expected to hop.

[DIENER, Neil, R., KLOPER, David, S., COLLINS, Anthony, T.] 20400 Observation Drive Suite 206 Germantown, MD 20876;10 Watchwater Way Rockville, MD 20850;1012 Leafy Hollow Circle Mt. Airy, MD 21771;48 Silver Moon Drive Silver Spring, MD 20904 An intelligent spectrum management (ISM) system and method are provided that includes sophisticated features to detect, classify, and locate sources of RF activity. The system comprises one or more sensor[2000] positioned at various locations in a region where activity in a shared radio frequency band is occurring and a server [3000] coupled to the sensors [2000]. Each sensor [2000] monitors communication traffic, such as IEEE WLAN traffic, as well as classifies non-WLAN signals occurring in the frequency band. The server [3000] receives data from each of the plurality of sensors [2000] and that executes functions to process the data supplied by the plurality of sensors [2000]. In particular, the server [3000] aggregates the data generated by the sensors [2000] and generates event reports and other configurable information derived from the sensors [2000] that is interfaced to a client application [4005], e.g., network management station.

[SUGAR, Gary, L., MASUCCI, Robert, M., TONER, Michael, F., RAHN, David, G.] 20400 Observation Drive Suite 206 Germantown, MD 20876;15307C Diamond Cove Terrace Rockville, MD 20850;1404 Kersey Lane Potomac, MD 20854;P.O. Box 11023 Station H Ottawa, Ontario K2H 7T8;31 Beaufort Drive Kanata, Ontario K2L 1Z5 A signal interfacing technique for connecting signals between a signal processing device (200) and a radio integrated circuit (IC) (150) involving multiplexing two or more signals on a connection pin (1-4) between the radio IC (150) and a signal processing device (200). 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 (1-4) from the signal processing device (200) to the radio IC (150), and during a receive mode a receive signal is coupled from the radio IC (150) on the connection pin (1-4) to the signal processing device (200). According to another technique, in-phase (I) and quadrature (Q) signals are multiplexed on a connection pin (1-4) during both transmit and receive modes.

[DIENER, Neil, R., FLOAM, Andrew, D., SUGAR, Gary, L., KLOPER, David, S.] Suite 206 20400 Observation Drive Germantown, MD 20876;10 Watchwater Way Rockville, MD 20850;1826 Briar Ridge Court Mclean, VG 22101;15307C Diamond Cove Terrace Rockville, MD 20850;1012 Leafy Hollow Circle Mt. Airy, MD 21771 A system and method for determining the location of a source (target device) of a wireless radio signal of an unknown or arbitrary type for which a signal correlator is not known or available. The target device’s signal is received at a plurality of known locations to generate receive sample data representative thereof at each known location. Receive signal data samples associated with the target device’s signal at one of the plurality of known locations is selected to be used as a reference waveform. For example, information concerning the target device’s signal received at each known location is compared to determine the known location that best receives it. The receive signal sample data obtained by the known location that best receives the target device’s signal is used as the reference signal. The reference signal and the target device’s signal are received at the plurality of known locations. The reference waveform is used to correlate against the received signal data obtained at each known location to determine the time of arrival of the target device’s signal. The time difference between arrival of the target device’s signal and arrival of the reference signal at each of the known locations is computed. A location of the source of the wireless radio signal is computed based on the time difference of arrival measurements at the plurality of known locations.

[VAIDYANATHAN, Chandra, SUGAR, Gary, L.] 20400 Observation Drive Suite 206 Germantown, MD 20876;10411 Montrose Avenue, #202 Bethesda, MD 20814;15307C Diamond Cove Terrace Rockville, MD 20850 Techniques are provided to correct for phase and amplitude mismatches in a radio device in order to maintain channel symmetry when communicating with another device using a multiple-input multiple output radio communication. Correction for the amplitude and phase mismatches among the plurality of transmitters and plurality of receivers of a device may be made at baseband using digital logic in the receiver path, the transmitter path or both paths of that device. Amplitude and phase offsets are determined among the plurality of radio transmitter and radio receiver paths by measuring phase and amplitude responses when supplying a signal to a transmitter in a first antenna path of the device and coupling the radio signal from a first antenna to a second antenna path of that device where the signal is down-converted by a receiver associated with the second antenna path.

[KLOPER, David, S., DIENER, Neil, R.] 20400 Observation Drive, Suite 206 Germantown, MD 20876;1012 Leafy Hollow Circle Mt. Airy, MD 21771;10 Watchwater Way Rockville, MD 20850 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 (210), sufficient knowledge of the frequency hopping sequence is derived (230) 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 (240). Using knowledge of future hop frequencies, operating parameters of a communication device or network can be adjusted (250) to mitigate interference with the frequency hopping signal.

[MACEDO, Jose, A., FONG, Neric, H., W., RAHN, David, G.] 20400 Observation Drive Suite 206 Germantown, MD 20876;150 Blackdome Crescent Kanata, Ontario, K2T 1A7;627-740 Springland Drive Ottawa, Ontario K1V 6L8;31 Beaufort Drive Kanata, Ontario K2L 1Z5 Tunable upconversion mixers (200) that have a controllable pass-band response and provide substantial image rejection, making costly post-mixing filtering at least optional, if not unnecessary for many applications. A single mixer is able to support several frequency bands (and/or be accurately tuned within one frequency band) by means of varying the capacitance in a tunable load circuit (130) for the mixer circuit. The tunable mixer (200) comprises a mixer circuit (110) having inputs for receiving a signal to be up-converted and an oscillator signal to be mixed with the signal to be up-converted. The mixer generates a mixer output signal at a desired sideband frequency and an image signal at an image frequency. A tunable load circuit (130) is coupled to the mixer circuit (110) and responsive to a control signal (134) to resonate and pass signals in a desired pass-band corresponding to the mixer output signal at the desired sideband frequency, and which attenuates signals in an attenuation band that includes the image signal at the undesired image frequency.

[SUGAR, Gary, L.] 20400 Observation Drive, Suite 206 Germantown, MD 20876;4835 Cordell Avenue, Apt 1415 Bethesda, MD 20814 Methods are provided for identifying devices that are sources of wireless signals from received radio frequency (RF) energy (710). RF energy is received at a device called a sensor device herein. Pulse metric data is generated from the received RF energy. The pulse metric data represents characteristics associated with pulses of received RF energy. The pulses are partitioned into groups based on their pulse metric data such that a group comprises pulses having similarities for at least one item of pulse metric data (720). Sources of the wireless signals are identified based on the partitioning process (760). The partitioning process involves iteratively subdividing each group into subgroups until all resulting subgroups contain pulses determined to be from a single source (750). At each iteration, subdividing is performed based on different pulse metric data than at a prior iteration. Ultimately, output data is generated (e.g., a device name for display) that identifies a source of wireless signals for any subgroup that is determined to contain pulses from a single source (790).

[DIENER, Neil, R.] 20400 Observation Drive Suite 206 Germantown, MD 20876;10 Watchwater Way Rockville, MD 20850 An intelligent spectrum management (ISM) system and method that includes sophisticated features to detect, classify, and locate sources of RF activity The system comprises one or more radio sensor devices (2000) positioned at various locations in a region where activity in a shared radio frequency band is occurring A server (3000) is coupled to the radio sensor devices (2000) and aggregates the data generated by the sensor devices (2000) Data collected and processed by the server (3000) from the sensors (2000) may be coupled to a console application (4005) that displays the data in desirable user interface format According to one aspect, the server (3000) continuously stores spectrum analysis data pertaining to activity in a frequency band over time and/or protocol analysis data pertaining to analysis of packets transmitted in the frequency band according to a communication protocol A console application (4005) includes a time-shift display mode that permits a user to specify an instant of time prior to the current time from which to playback spectrum analysis data and/or protocol analysis data generated by one or more radio sensor devices (2000).

[SUGAR, Gary L., VAIDYANATHAN, Chandra] 20400 Observation Drive Suite 206 Germantown, MD 20876;15307C Diamond Cove Terrace Rockville, Maryland;10411 Montrose Avenue, #202 Bethesda, MD 20814 A system, method and device for MIMO radio communication of multiple signals between a first device (100) having N plurality of antennas (110) and a second device (200) having M plurality of antennas (210). At the first device, a vector s representing L signals to be transmitted is processed with a transmit matrix A to maximize capacity of the channel between the first device and the second device subject to a power constraint that the power emitted by each of the N antennas is less than or equal to a maximum power. The power constraint for each antenna may be the same for all antennas or specific or different for each antenna. For example, the power constraint for each antenna may be equal to a total maximum power emitted by all of the N antennas combined divided by N. The transmit matrix A distributes the L signals among the N plurality of antennas for simultaneous transmission to the second device. At the second device, the signals received by the M plurality of antennas are processed with receive weights and the resulting signals are combined to recover the L signals.