Abstract: In general, techniques are described for sensing wireless communications in television frequency bands, which may be implemented by a sensing device comprising a sensing unit, a power spectral density (PSD) estimation unit, a filter unit, a candidate selection unit, an analysis unit and a decision unit. The sensing unit senses a signal in the television frequencies bands. The PSD estimation unit calculates an estimate of a PSD for the sensed signal. The filter unit filters the estimated PSD. The candidate selection unit analyzes the filtered PSD to identify a candidate frequency representative of a potentially in use frequency. The analysis unit computes a test statistic for the candidate frequency. The decision unit compares the test statistic to a threshold to identify whether the candidate frequencies is actively in use by wireless communication devices.

Abstract: Methods and apparatus for sensing features of a signal in a wireless communication system are disclosed. The disclosed methods and apparatus sense signal features by determining a number of spectral density estimates, where each estimate is derived based on reception of the signal by a respective antenna in a system with multiple sensing antennas. The spectral density estimates are then combined, and the signal features are sensed based on the combination of the spectral density estimates.

Abstract: Transmitting devices facilitate privacy protection of content broadcasted from the transmitting device to a receiving device without the need to modify the receiving device. A transmitting device may be adapted to acquire content, such as audio and/or video data, to be broadcasted by the transmitter for reception and use by a receiving device. A transmission range is selected to define a distance for broadcasting the content from the transmission device for reception and use by a receiving device. A frequency is also selected to be used for broadcasting the content. With the transmission range and frequency selected, the transmitting device may broadcast the content according to the selected transmission range and frequency.

Abstract: The use of white space devices in unused portions of the television channel spectrum is facilitated by spectrum sensing techniques that combine interference rejection techniques with feature extraction techniques to detect presence or absence of incumbent users in the spectrum.

Abstract: An apparatus, a cognitive radio, a processor, a method, and a machine-readable medium for detecting a presence of a signal in a communication channel are disclosed. An apparatus includes a processor configured to select one or more peak samples of two or more fields of a sampled signal and configured to determine one or more absolute values of the one or more peak samples of the two or more fields. In addition, the processor is configured to superimpose the one or more absolute values of the one or more peak samples of the two or more fields. The processor is further configured to combine the one or more absolute values that fall within a predetermined window to produce a peak value and configured to compare the peak value with a threshold to determine a presence of a signal in the communication channel.

Abstract: Multichannel dynamic frequency selection in wireless networks begins with an access point for a wireless network broadcasting a list of unused channels that are available for communication within the area served by the access point. The various access terminals within this service area receive the broadcast and measure various interference characteristics of each of the channels in the list. The access terminals then send this interference information to the access point, which compiles a matrix of interference information that is associated with the quality of each signal as related to each access terminal. Using this information, the access point selects the appropriate channels to serve the most number of access terminals at the highest possible channel qualities.

Abstract: Techniques for use in contending for a portion of a television channel spectrum are disclosed. In some instances, a back-off value is used to decide whether a contender's contention number will be transmitted when the contention channel is free, and the back-off value is determined based on the contention number. In some instances, a contender monitors the contention channel and withdraws from contention if it detects from the contention channel that a higher priority contender is in contention.

Abstract: Methods and apparatus for providing a wireless expansion network. In an aspect, an apparatus includes an expansion circuit configured to identify at least one of a selected uplink (UL) channel and a selected downlink (DL) channel that are provided by one of a primary network and an expansion network, and a processing circuit configured to switch to the at least one of the selected UL and DL channels. An apparatus includes means for obtaining link parameters associated with a primary network and an expansion network, means for identifying clients that are assigned transmission channels on both the primary network and the expansion network based on the link parameters, and means for transmitting messages to the clients to indicate the assigned transmission channels.

Abstract: Certain aspects of the present disclosure provide techniques for detecting presence of a Bluetooth device in the vicinity of a WiFi device by sensing the spectrum of the Bluetooth device using a sequence of energy detection measurements, generating a test statistic based on the measurements and comparing the test statistic to a threshold.

Abstract: A spatio-temporal random voting scheme is provided that incorporates location distribution, spatial randomness, and temporal randomness in the collection of information from a plurality of sensing devices within the cognitive network. The region is divided into a plurality of sectors, where each sector is a portion of the region. A subset of sectors is selected from the plurality of sectors in the region to provide spatial randomness. A device is randomly selected from each sector in the subset of sectors to provide additional spatial randomness to the information collection process. Temporal randomness may be introduced by randomly selecting a timeslot within a sensing window period in which devices are to scan a frequency spectrum band to determine if a signal energy above a threshold is detected. Sensing reports are then collected from the selected sensing devices and used to determine whether the frequency spectrum band is available or in use.

Abstract: Methods and apparatus for sensing the presence of a transmission signal type within a wireless channel in a wireless communication system, such as those including the use of wireless microphones, are described. Sensing the transmission signal type includes calculating a spectral density estimate of a signal on the wireless channel. A first test value, derived from the calculated spectral density estimate, is compared to a first threshold. A preliminary determination of the presence of the transmission signal type is made if the first test value exceeds the first threshold. Sensing the presence of the signal type after preliminary determination of the presence of the signal type is made by determining that an observed spectral density of a prescribed signal added to the signal on the wireless channel matches a model estimate of the spectral density of the prescribed signal to a sufficient degree.

Abstract: Methods and apparatus for determining if a signal of interest, for example, a licensed signal having or exceeding a predetermined field strength, is present in a wireless spectrum and/or which facilitates such a determination are described. The signal of interest maybe, e.g., a television signal or a wireless microphone signal using licensed television spectrum. The predetermined field strength may be specified or by a government regulation or rule.

Abstract: A method for detecting the presence of a transmission signal in a wireless spectrum channel. The frequency of a signal is converted from a first frequency to a second frequency. The signal with the second frequency is filtered to remove signals that are not within the band of the second frequency. An averaged periodogram of the signal is calculated. A value of the averaged periodogram is compared to a threshold. The presence of the transmission signal is detected, if the value of the averaged periodogram exceeds the threshold.

Abstract: Techniques are provided for frequency coordination among two different wireless network protocols, such as the IEEE 802.11 and Bluetooth protocols, operating in proximity with one another. Coordination is accomplished by the use of a first radio transceiver operating in accordance with a first communication protocol (which may be the 802.11 protocol) and using a frequency band (which may be the 2.4 GHz band), a base station connected to a wired network and operating in accordance with the first communication protocol, a second radio transceiver operating in accordance with a second communication protocol (which may be the Bluetooth protocol) and using the frequency band, and a coordinator associated with the base station for, in turn, activating the first radio transceiver, deactivating the first radio transceiver, activating the second radio transceiver, and deactivating the second radio transceiver.

Abstract: A method and apparatus for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords. The two dimensional bar code is scanned with a scanning pattern oriented such that a plurality of lines thereof cross the bar code rows. A determination if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line is made and the orientation of the scanning pattern is adjusted to reduce the absolute value of the angle.

Abstract: A system and method described for tracking portable devices. The system may include a transmitter which transmits wireless inquiries to a plurality of portable devices and a receiver receiving replies to the inquiries from the portable devices. In addition, the system may include a memory storing identifier data corresponding to the portable devices and a processor coupled to the memory and to the receiver, the processor retrieving from each reply, identifier data uniquely identifying a particular one of the portable devices which generated the reply and comparing the identifier data to the stored identifier data. Furthermore, the system may include an alarm system coupled to the processor and controlled based on the comparison of stored identifier data to the identifier data retrieved from the replies.

Abstract: A portable data input or computer system includes an input/output device such as a keyboard and a display, another data input device such as an optical bar code scanner, and a data processor module. To scan bar code type indicia, the operator points the scanner at the bar code and triggers the scanner to read the indicia. All the system components are distributed on an operator's body and together form a personal area system (PAS). Components may include a scanner or imager, a wrist unit, a headpiece including an eyepiece display, speaker and a microphone. Components within a particular PAS communicate with each other over a personal area network (PAN). Individual PASs may be combined into a network of PASs called a PAS cluster. PASs in a particular PAS cluster can communicate with each other over another wireless communication channel. Individual PAS can gain access to a Local Area Network (LAN) and/or a Wide Area Network (WAN) via an access point.

Abstract: Wireless data communications using a master/slave protocol are easily established between a master radio module which is part of a POS terminal and a slave radio module which is part of a portable bar code scanning device. A bar code identifying the portable bar code scanning device is provided on the outside of the housing of the portable device. By scanning this bar code with a scanner associated with the POS terminal, such as a fixed scanner built onto a counter, the master/slave radio communications link can be automatically implemented.

Abstract: A signaling arrangement and method for use in a wireless local area network managed by a system manager include a reader for electro-optically reading bar code symbols. The system manager verifies that a symbol has been successfully read and sends an acknowledgment signal by wireless, radio frequency transmission to a remote indicator operative for generating an alert signal noticeable to a user.

Abstract: A method and apparatus for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords. The two dimensional bar code is scanned with a scanning pattern oriented such that a plurality of lines thereof cross the bar code rows. A determination if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line is made and the orientation of the scanning pattern is adjusted to reduce the absolute value of the angle.