Abstract: A given computer graphics scene may be rendered as a set of triangles. A set of photons may be distributed over the scene, and a number of steps may be performed for each triangle. For each triangle, a list of photons may be constructed. For that triangle, a set of control points may be identified for purposes of determining global illumination. For each control point, a specific illumination estimate may be computed. A kd-tree of the control points of the triangle may be built. An illumination estimate may then be drive for the triangle.

Abstract: Embodiments of the invention provide for accelerated polygon intersection testing of rays against a set of polygons. The amount of computation required in the rendering process is reduced by preprocessing the scene into a data structure that can be more efficiently traversed. During the preprocessing stage, triangles such as triangle may be converted into vertex and edge representation.

Abstract: Embodiments provide for ray tracing traversal that relies on selected geometrical properties of the application to reduce the number of operations required during each traversal step. The traversal algorithm does not depend on the number of rays in the group. As a result, multi-level traversal schemes may be implemented, starting with a large number of rays in a group and then reducing it as needed to maintain group coherency. Multi-level traversal schemes may be created by splitting large groups of rays while traversing acceleration structures.

Abstract: A method, apparatus, and system related to thermal management. The method includes generating a beam including a group of rays; evaluating the beam against a spatially ordered geometrical database until the beam can no longer be evaluated as a whole in order to discard a portion of the spatially ordered geometrical database from further consideration; noting the location where the beam can no longer be evaluated as a whole; and traversing, starting at the noted location, the spatially ordered geometrical database for each of the rays by executing a query against the spatially ordered geometrical database not discarded by the evaluating.

Abstract: An apparatus and method for soft shadow calculations, the method including dividing an area light source into a patch of points, obtaining a packet of points on a surface that is subject to illumination by the patch of points, determining a form-factor value for each of the points in the packet of points; and simultaneously performing adaptive soft shadow calculations for each of the points in the packet based on the point in the packet having the greatest form-factor.

Abstract: An OFDM receiver applies phase compensation to subcarriers of data symbols of an OFDM packet. A phase compensation estimate is generated from pilot subcarriers within the data symbol and applied to the subcarriers of the data symbol prior to demapping. The pilot subcarriers of the data symbol are combined and weighted to generate an observation vector. Recursive filtering is performed on the observation vector to generate the phase compensation estimate. The recursive filtering may include performing an extended Kalman-type filtering (EKF) operation on the observation vector using a channel estimate, an additive noise power estimate, a signal to noise ratio (SNR) estimate and a priori information about a dynamic model of the phase noise spectrum of transceiver oscillators. The channel estimate may be generated from a long training symbol of the OFDM packet, and the additive noise power estimate and the SNR estimate may be generated from short training symbols of the OFDM packet.

Abstract: A method, apparatus, and system related to thermal management. The method includes generating a beam including a group of rays; evaluating the beam against a spatially ordered geometrical database until the beam can no longer be evaluated as a whole in order to discard a portion of the spatially ordered geometrical database from further consideration; noting the location where the beam can no longer be evaluated as a whole; and traversing, starting at the noted location, the spatially ordered geometrical database for each of the rays by executing a query against the spatially ordered geometrical database not discarded by the evaluating.

Abstract: Embodiments provide for ray tracing traversal that relies on selected geometrical properties of the application to reduce the number of operations required during each traversal step. The traversal algorithm does not depend on the number of rays in the group. As a result, multi-level traversal schemes may be implemented, starting with a large number of rays in a group and then reducing it as needed to maintain group coherency. Multi-level traversal schemes may be created by splitting large groups of rays while traversing acceleration structures.

Abstract: Embodiments provide for ray tracing traversal that relies on selected geometrical properties of the application to reduce the number of operations required during each traversal step. The traversal algorithm does not depend on the number of rays in the group. As a result, multi-level traversal schemes may be implemented, starting with a large number of rays in a group and then reducing it as needed to maintain group coherency. Multi-level traversal schemes may be created by splitting large groups of rays while traversing acceleration structures.

Abstract: An orthogonal frequency division multiplexed (OFDM) receiver achieves improved frequency synchronization by generating a fine frequency offset of an OFDM packet with a two-channel frequency offset estimation scheme. Concurrent autocorrelations are performed with training symbols delayed by one and two durations of the training symbols. The respective correlation outputs are integrated over one and a half durations and one half duration to generate phase shift estimates. The phase shift estimates are weighted and combined to generate the fine frequency offset estimate which is used to rotate the phase of OFDM data symbols prior to performing a Fast Fourier Transform (FFT) on the data symbols.

Abstract: An OFDM packet is initially detected by auto-correlating short training symbols to generate an initial packet detection signal. The initial packet detection signal may be used to initiate a coarse timing synchronization process, which may use a short symbol matched filter. A coarse timing signal may be generated from at least some of the short training symbols by correlating sampled short training symbols with short filter matched coefficients. The coarse-timing signal may be used to initiate the operation of a fine timing synchronization process, which may use a long symbol matched filter. A fine timing signal may be generated from at least some of the long training symbols by correlating sampled long training symbols with long filter-matched coefficients. The fine timing signal may be used to initiate channel estimation by performing a Fast Fourier Transform (FFT) operation on the long training symbols.

Abstract: An OFDM receiver applies phase compensation to subcarriers of data symbols of an OFDM packet. A phase compensation estimate is generated from pilot subcarriers within the data symbol and applied to the subcarriers of the data symbol prior to demapping. The pilot subcarriers of the data symbol are combined and weighted to generate an observation vector. Recursive filtering is performed on the observation vector to generate the phase compensation estimate. The recursive filtering may include performing an extended Kalman-type filtering (EKF) operation on the observation vector using a channel estimate, an additive noise power estimate, a signal to noise ratio (SNR) estimate and a priori information about a dynamic model of the phase noise spectrum of transceiver oscillators. The channel estimate may be generated from a long training symbol of the OFDM packet, and the additive noise power estimate and the SNR estimate may be generated from short training symbols of the OFDM packet.

Abstract: An orthogonal frequency division multiplexed (OFDM) receiver achieves improved frequency synchronization by generating a fine frequency offset of an OFDM packet with a two-channel frequency offset estimation scheme. Concurrent autocorrelations are performed with training symbols delayed by one and two durations of the training symbols. The respective correlation outputs are integrated over one and a half durations and one half duration to generate phase shift estimates. The phase shift estimates are weighted and combined to generate the fine frequency offset estimate which is used to rotate the phase of OFDM data symbols prior to performing a Fast Fourier Transform (FFT) on the data symbols.

Abstract: An OFDM packet is initially detected by auto-correlating short training symbols to generate an initial packet detection signal. The initial packet detection signal may be used to initiate a coarse timing synchronization process, which may use a short symbol matched filter. A coarse timing signal may be generated from at least some of the short training symbols by correlating sampled short training symbols with short filter matched coefficients. The coarse-timing signal may be used to initiate the operation of a fine timing synchronization process, which may use a long symbol matched filter. A fine timing signal may be generated from at least some of the long training symbols by correlating sampled long training symbols with long filter-matched coefficients. The fine timing signal may be used to initiate channel estimation by performing a Fast Fourier Transform (FFT) operation on the long training symbols.