Abstract: Embodiments of the invention provide a method of decoding of hexagonal constellations. The decoding methods exploit the inherent structure of the hexagonal grid to eliminate/minimize the requirements for distance computations. A constellation which has unused constellation points is received. A plurality of lookup tables is used for indicating whether a particular constellation point is used. The lookup tables are indexed using the two integers u and v. An initial estimate ? and v is found. The euclidean distance to the immediate neighbors resulting in the immediate upper and lower integers for ? and v is computed. From the distance to the nearest neighbor, the log-likelihood ratio value is computed.

Abstract: A wireless device that includes an access point (AP) scanner, a transceiver, and a controller coupled to the AP scanner and transceiver. The AP scanner is configured to scan wireless network channels utilized by one or more APs to transmit data packets, probe responses, and beacons. The transceiver is configured to transmit one or more probe requests to the one or more APs and receive one or more probe responses and beacons from the one or more APs. The controller is configured to determine a proximate geographic position of the wireless device based on signal strength of the one or more probe responses and beacons received from the one or more APs. The controller also dynamically adapts a parameter utilized in determining the proximate geographic position of the wireless device.

Abstract: Embodiments of the invention provide a method of decoding of hexagonal constellations. The decoding methods exploit the inherent structure of the hexagonal grid to eliminate/minimize the requirements for distance computations. A constellation which has unused constellation points is received. A plurality of lookup tables is used for indicating whether a particular constellation point is used. The lookup tables are indexed using the two integers u and v. An initial estimate of u and v is found. The euclidean distance to an immediate four neighbors resulting in the immediate upper and lower integers for ? and v. The upper or lower integer that corresponds to the smalling distance is selected and all other immediate neighbors are computed. Assignment of constellation points on the hexagonal grid for a given constellation size is provided which exploits the inherent redundancy provided by the hexagonal grid.

Abstract: Apparatus and method for dynamically updating a channel model used for wireless local area network based positioning. In one embodiment, a wireless device includes a positioning system. The positioning system is configured to determine a position of the device based on signals received from wireless local area network access points. The positioning system is also configured to determine a likelihood that the wireless device is positioned at each of a plurality of points of a positioning grid based on a received signal strength value for each of a plurality of access points. The positioning system is further configured to update a reference power estimate for each access point based on the likelihoods. The positioning system is also configured to update the path loss exponent of the channel model.

Abstract: Apparatus and method for positioning using map-assisted Kalman filtering. In one embodiment, a wireless device includes a positioning system configured to determine a position of the device based on wirelessly received positioning signals. The positioning system is configured to compute, via a Kalman filter, an initial location of the wireless device. The positioning system is also configured to determine whether the initial location is within a polygon defining a prohibited geographic area. The positioning system is further configured to identify an edge of the polygon nearest the initial location, based on the initial location being determined to be within the polygon. The positioning system is yet further configured to provide information defining the edge of the polygon to the Kalman filter as a measurement for use in computing a final position of the wireless device.

Abstract: Apparatus and method for positioning a device based on wireless local area network signals. In one embodiment, a wireless local network positioning system includes access point selection logic. The access point selection logic includes likelihood computation logic, minimum mean squared error (MMSE) estimation logic, variance computation logic, and access point exclusion logic. The likelihood computation logic is configured to compute a likelihood value for each access point and point of a positioning grid. The MMSE estimation logic is configured to compute an MMSE estimate based on the likelihood values. The variance computation logic is configured to compute an MMSE variance for the MMSE estimate. The access point exclusion logic is configured to determine whether excluding a selected one of the access points reduces the MMSE variance, and to exclude the selected access point from the access points used for positioning, based on the exclusion reducing the MMSE variance.

Abstract: An imaging device, is provided, comprising: a plurality of compression circuits configured to receive K initial imaging signals and to generate second through Kth modified imaging signals, and a plurality of delay values; and a bit multiplexer configured to generate a compressed bit stream based on a first imaging signal, second through Kth modified imaging signals, and the delay values, each compression circuit including: a delay computer configured to determine a delay value by comparing two adjacent initial imaging signals, a delay circuit configured to delay a first of the two adjacent imaging signals by the delay value to generate a delayed imaging signal; a subtractor configured to subtract the delayed signal from a second of the two adjacent imaging signals to generate a reduced imaging signal; and a quantizer configured to generate a quantized imaging signal corresponding to the second of the two adjacent imaging signals.

Abstract: Embodiments of the invention compress ultrasound RF data after the receiver beamformer. An efficient compression algorithm is disclosed that incorporates the use of the Discrete Cosine Transform (DCT) and the Discrete Wavelet Packet (DWP) transform, followed by quantization of the wavelet coefficients. The algorithm first processes ultrasound scanlines from the receiver beamformer using a DCT transform. In a low-power configuration, a Hadamard transform may be used instead of the DCT. The output of the DCT processing is DCT coefficients at different frequencies. An optimized wavelet packet transform is then used for each coefficient line. The wavelet filter kernels and the wavelet packet trees can be jointly optimization using a two-step optimization algorithm.

Abstract: An imaging device is provided, comprising: a decorrelation circuit configured to receive K initial imaging signals and to perform a decorrelation operation on K initial imaging signals, respectively, to generate K decorrelated imaging signals; Kh wavelet decomposition circuits configured to perform K wavelet decomposition operations on the K decorrelated imaging signals, respectively, to generate K decomposed imaging signals; K quantization circuits configured to perform K quantization operations on the K decomposed imaging signals, respectively, to generate K quantized imaging signals; and a bit multiplexer configured to generate a compressed bit stream based on the K quantized imaging signals; a data line configured to pass the compressed bit stream; and a decompressor module configured to convert the compressed bit stream into K recovered imaging signals corresponding to the K initial imaging signals, wherein K is an integer greater than 1.

Abstract: Embodiments of the invention compress ultrasound RF data after the receiver beamformer. An efficient compression algorithm is disclosed that incorporates the use of the Discrete Cosine Transform (DCT) and the Discrete Wavelet Packet (DWP) transform, followed by quantization of the wavelet coefficients. The algorithm first processes ultrasound scanlines from the receiver beamformer using a DCT transform. In a low-power configuration, a Hadamard transform may be used instead of the DCT. The output of the DCT processing is DCT coefficients at different frequencies. An optimized wavelet packet transform is then used for each coefficient line. The wavelet filter kernels and the wavelet packet trees can be jointly optimization using a two-step optimization algorithm.

Abstract: An imaging device, is provided, comprising: a plurality of compression circuits configured to receive K initial imaging signals and to generate second through Kth modified imaging signals, and a plurality of delay values; and a bit multiplexer configured to generate a compressed bit stream based on a first imaging signal, second through Kth modified imaging signals, and the delay values, each compression circuit including: a delay computer configured to determine a delay value by comparing two adjacent initial imaging signals, a delay circuit configured to delay a first of the two adjacent imaging signals by the delay value to generate a delayed imaging signal; a subtractor configured to subtract the delayed signal from a second of the two adjacent imaging signals to generate a reduced imaging signal; and a quantizer configured to generate a quantized imaging signal corresponding to the second of the two adjacent imaging signals.

Abstract: An imaging device is provided, comprising: a decorrelation circuit configured to receive K initial imaging signals and to perform a decorrelation operation on K initial imaging signals, respectively, to generate K decorrelated imaging signals; Kh wavelet decomposition circuits configured to perform K wavelet decomposition operations on the K decorrelated imaging signals, respectively, to generate K decomposed imaging signals; K quantization circuits configured to perform K quantization operations on the K decomposed imaging signals, respectively, to generate K quantized imaging signals; and a bit multiplexer configured to generate a compressed bit stream based on the K quantized imaging signals; a data line configured to pass the compressed bit stream; and a decompressor module configured to convert the compressed bit stream into K recovered imaging signals corresponding to the K initial imaging signals, wherein K is an integer greater than 1.

Abstract: A method and apparatus for low delay recursive filter design. The method includes determining a predefined filter template with higher magnitude specification than a target filter design, determining at least one relaxation bound on the filter specification utilizing the predefined filter template, specifying at least one constraint for the target filter design utilizing the at least one relaxation bound, and determining a low delay recursive filter design for minimizing the average group delay of the filter utilizing the at least one constraint.

Abstract: A method and apparatus for transcoding audio data. The method includes determining if AAC joint stereo exists, running a reference AC-3 rematrixing when the AAC joint stereo does not exist, when AAC joint stereo does exist, enabling rematrixing when the number of corresponding AAC bands is greater than half the size of the band, otherwise, running reference AC-3 rematrixing.