Abstract: In one embodiment, the present invention is a technique for processing fragments received at a node (e.g., a router) in a datagram-based communication system in order to provide a wide range of protection against potential fragment-based attacks. Received fragments are examined as they are received to verify that they do not overlap one another and that the fragment sequence does not exploit common weaknesses in IP packet-reassembly algorithms. Valid fragment sequences that represent potential threats to the receiver can be reordered and/or fully or partially re-assembled and re-fragmented into a fragment sequence that eliminates or reduces the threat to the receiver. Fragmented sequences that represent a likely attack are blocked, as are subsequent fragments of the associated packet.

Abstract: An optical communication system having an optical transmitter and an optical receiver optically coupled via a multi-path fiber. The optical transmitter launches, into the multi-path fiber, an optical transverse-mode-multiplexed (TMM) signal having a plurality of independently modulated components by coupling each independently modulated component into a respective transverse mode of the multi-path fiber. The TMM signal undergoes inter-mode mixing in the multi-path fiber before being received by the optical receiver. The optical receiver processes the received TMM signal to reverse the effects of inter-mode mixing and recover the data carried by each of the independently modulated components.

Abstract: An electronic audio device with a digital audio output channel in which an amplifier output voltage is gradually ramped up and down to avoid causing a popping sound when the device is turned on and off. This is accomplished without employing any additional hardware, by incrementally changing a digital input word applied to a digital audio source, such as a DSP, so as to gradually change the amplifier output voltage between a minimum, such as zero volts, and a DC working voltage. On powering up, the amplifier is only turned on after the digital word is applied, but while it still results in a minimum amplifier output, and on powering down the amplifier is turned off after it's output has been ramped down, but before removing the digital input word. Sources and output channels can also be switched over by powering down, and then powering up, following the same method.

Abstract: In one embodiment, an LDPC decoder has a controller and one or more check-node units (CNUs). The CNUs generate check-node messages using a scaled min-sum algorithm, an offset min-sum algorithm, or a scaled and offset min-sum algorithm. Initially, the controller selects a scaling factor and an offset value. The scaling factor may be set to one for no scaling, and the offset value may be set to zero for no offsetting. If the decoder is unable to correctly decode a codeword, then (i) the controller selects a new scaling and/or offset value and (ii) the decoder attempts to correctly decode the codeword using the new scaling and/or offset value. By changing the scaling factor and/or offset value, LDPC decoders of the present invention may be capable of improving error-floor characteristics over LDPC decoders that use only fixed or no scaling factors or fixed or no offsetting factors.

Abstract: An optical-disc player having a reader and a controller. The reader derives out-of-band information from surface marks of an optical disc, where the controller controls operations of the reader based on the derived information. The controlled operations may involve the reading and rendering of embedded data of the optical disc. For example, a person writes the words “Spanish” and “widescreen” on the surface of a DVD with a marker and inserts the DVD in a DVD player. The DVD player scans the surface of the DVD and sends the resulting image data to an optical character recognition (OCR) module. The OCR module outputs a text file containing the words “Spanish” and “widescreen” to a controller (e.g., Microsoft HDi runtime). In response, the controller sets the playback language to Spanish and the screen format to widescreen.

Abstract: A system and method for conducting a game with two or more participants that provides selections of the final two contestants for a particular contest. In the game, at least one winning participant is determined by comparing each participant's selections of the final two contestants to the actual final two contestants in the contest. Participants may also provide an indication of the first place contestant from among the selected final two contestants. Ties may be broken by comparing each participant's selection of a first place contestant to the actual first place contestant in the contest. Also described is a system for implementation of the method including means for carrying out the steps of the method. The method and system provide a fun, straightforward game that can be adapted to a wide variety of contests, be played by a large number of participants and be implemented over the World Wide Web.

Abstract: A technique for estimating the Doppler frequency of an input signal comprising a pilot signal. In one embodiment, the technique comprises: (a) accumulating a plurality of samples from the input signal over a specified time duration to derive a channel tap estimate; (b) obtaining a sequence of channel tap estimates by repeating step (a) until a specified number of channel tap estimates have been accumulated; (c) performing a Fourier transform of the sequence of channel tap estimates to obtain a complex sequence of values; (d) finding the smallest index value for which a power spectral distribution function of the complex sequence of values exceeds a specified threshold; and (e) obtaining an estimate of the Doppler frequency by dividing the smallest index value found in step (d) by the product of the specified number of channel tap estimates and the specified time duration.

Abstract: In one embodiment, a reconfigurable minimum operator has two five-bit non-reconfigurable minimum operators and is selectively configurable to operate in a five- or ten-bit mode. In five-bit mode, the first non-reconfigurable minimum operator determines whether a first five-bit message is less than a second five-bit message, and the second non-reconfigurable minimum operator determines whether a third five-bit message is less than a fourth five-bit message. In ten-bit mode, the first non-reconfigurable minimum operator determines whether a first half of a first ten-bit message is less than a first half of a second ten-bit message, and the second non-reconfigurable minimum operator determines whether a second half of the first ten-bit message is less than a second half of the second ten-bit message. The reconfigurable minimum operator determines whether the first ten-bit message is less than the second ten-bit message based on the comparisons of the first and second non-reconfigurable minimum operators.

Abstract: In one embodiment, a signal processing receiver has a branch-metric calibration (BMC) unit that receives (i) sets of four hard-decision bits from a channel detector and (ii) a noise estimate. The BMC unit has two or more update blocks (e.g., tap-weight update and/or bias-compensation blocks) that generate updated parameters used by a branch-metric unit of the channel detector to improve channel detection. The two or more update blocks generate the updated parameters based on (i) the sets of four hard-decision bits, (ii) the noise estimate, and (iii) bandwidth values. The bandwidth values for at least two of the two or more update blocks are selected such that they are different from one another. Selecting different bandwidth values may reduce the bit-error rate for the receiver over the bit-error rate that may be achieved by selecting the bandwidth values to be the same as one another.

Abstract: In one embodiment of the invention, decompressed video signals are upscaled and then filtered using a combined mosquito noise reduction (MNR) and aliasing coring filter that reduces both mosquito noise in the decompressed video signals as well as aliasing noise resulting from the upscaling process. In one implementation, the combined coring filter includes a dual-band filter having two passbands interleaved with two stopbands. The strength of the coring filter may be dynamically controlled based on compression information (e.g., quantizer scales indicative of video quality) associated with the compressed video bitstream from which the decompressed video is recovered.

Abstract: In one embodiment, a reconfigurable two's-complement-to-sign-magnitude (2TSM) converter has two five-bit non-reconfigurable 2TSM converters and is selectively configurable to operate in a five-bit mode or a ten-bit mode. In five-bit mode, the first and second non-reconfigurable 2TSM converters concurrently convert first and second five-bit messages, respectively, from two's-complement-to-sign-magnitude format. In the ten-bit mode, the first and second non-reconfigurable 2TSM converters concurrently convert first and second halves of a ten-bit message, respectively, from two's-complement-to-sign-magnitude format. The reconfigurable 2TSM converter then generates a ten-bit sign-magnitude message based on the conversions of the two non-reconfigurable 2TSM and a carry-over bit. In another embodiment, a reconfigurable sign-magnitude-to-two's-complement (SMT2) converter comprises the reconfigurable 2TSM described above.

Abstract: In one embodiment, a coherent optical receiver has an optical detector coupled to a digital processor. The optical detector mixes a received modulated optical signal with a local-oscillator signal to produce a digital measure of the modulated optical signal. The digital processor processes the digital measure using a primary carrier- and data-recovery (CDR) stage and one or more secondary CDR stages serially connected to one another. The processing performed in each secondary CDR stage is decision-directed and uses the symbol estimate generated by the preceding CDR stage to obtain a respective estimate of the carrier-phase offset and a respective symbol estimate. Since each subsequent CDR stage typically improves the accuracies of its estimates compared to those of the preceding CDR stage(s), the receiver has a lower bit-error rate than a receiver employing a single CDR stage.

Abstract: In one embodiment, a method for estimating the number of tags in a set of tags in a system of tags and readers. The method includes, during each of a plurality of time intervals: (i) transmitting a command requesting that each tag that receives the command determine whether to transmit a reply; and (ii) receiving, in one or more timeslots of a frame corresponding to the time interval, replies from one or more tags. The method further includes providing an estimate of the number of tags in the set of one or more tags based on (i) timeslots in each of the plurality of time intervals that are zero timeslots, i.e., timeslots having no received reply, and (ii) the total number of timeslots in each frame.

Abstract: A method for representing, in a network data structure, a minimum amount of protection bandwidth required to be reserved on each link in a mesh network, to restore service upon failure of another node or link in the network. The method includes (1) receiving a request for a new service in the network, wherein the new service is represented by a service data structure having an identification of each link and transit node in a primary path for the new service, (2) determining, using the network and service data structures, whether the new service requires additional protection bandwidth to be reserved on any link in the network, and (3) updating the network data structure if any additional protection bandwidth is determined to be needed. In one implementation the network and service data structures are vectors and the steps of determining and updating involve vector operations between these structures.

Abstract: In a microwave heating apparatus, the fundamental TE10 mode of the standard waveguide (5) having a standard rectangular cross-section is fed into an elongated heating cavity (2) having an enlarged rectangular cross-section in which the shorter side of the standard waveguide is enlarged to a length which can accommodate the desired width of a board (8) to be heated. A pair of lateral slots (25) is provided parallel in the opposite enlarged walls (11) of the heating cavity (2) to form a track for the board (8) to travel across the cavity. As the initially longer sidewall (11) of the standard waveguide is unchanged, the fundamental mode is not affected but the electric field is uniformly distributed along the width of the board (8) traversing the electric field and the cavity. As a result, wider products can be heated and a more uniform heating pattern can be achieved.

Abstract: In one embodiment, a method for writing data to a storage-device array (i) including three or more storage devices and (ii) having a plurality of stripes, each stripe having two or more sector levels, each sector level containing one sector on each storage device in the array at corresponding addresses across the storage devices. The method includes: (a) calculating a parity index based on (i) an index value for a current stripe and (ii) the number of storage devices in the array, the parity index identifying a first storage device for parity data for the current stripe; and (b) at each sector level of the current stripe: (b1) writing parity data to the first storage device identified by the parity index; and (b2) writing information to the remaining storage devices.

Abstract: Certain embodiments of the present invention are improved turbo-equalization methods for decoding encoded codewords. In one embodiment, in global decoding iteration i, the magnitude values of all decoder-input LLR values (Lch) are adjusted based on the number b of unsatisfied check nodes in the decoded codeword produced by global iteration i?1. The improved turbo-equalization methods can be used as the sole turbo-equalization method for a given global decoding session, or interleaved with other turbo-equalization methods.

Abstract: A lightweight probabilistic mechanism used to estimate the number of active flows, which estimate is used to determine the probability of admitting a new flow into the network. In one embodiment, a method for controlling admission of new flows at a node in a network of nodes interconnected by links includes: (a) for each of a plurality of incoming packets arriving at the node, each incoming packet corresponding to an active flow traversing the node: (a1) randomly selecting a packet from an output buffer of the node; (a2) determining whether the incoming packet is from the same active flow as the randomly-selected packet; and (a3) updating an estimate of the number of active flows traversing the node based on the determination of step (a2); and (b) determining whether to admit or drop part or all of a new flow at the node based on the estimated number of active flows traversing the node.

Abstract: In one embodiment, a receiver is provided for use in a multiple-input system that includes a receiving antenna receiving a time-domain signal corresponding to a plurality of signals transmitted from a plurality of transmitting antennas. The receiver includes: (a) a transform unit adapted to transform the time-domain signal into a frequency-domain signal; (b) a channel estimation unit adapted to estimate, based on the frequency-domain signal and a frequency-domain pilot signal, a combined transfer function corresponding to a plurality of transfer functions of respective channels between the plurality of transmitting antennas and the receiving antenna; and (c) a channel separation unit including a plurality of frequency-domain convolution units that separate the combined transfer function into a plurality of estimated channel transfer functions.

Abstract: In one embodiment, a telecommunication device for Internet-based conference calling with one or more similar telecommunication devices. The telecommunication device is used by a plurality of co-located participants, each participant having an individually identifiable microphone. The telecommunication device accesses a database correlating each individually identifiable microphone to participant ID and information. During the conference-call setup, the similar telecommunication devices exchange participant IDs and corresponding information. The conference-call audio content is then exchanged using RTP packets, where the telecommunication devices generate RTP packets containing the participant IDs of participants contributing to the content of each RTP packet. Receiving telecommunication devices then display corresponding participant information when playing the audio content of received RTP packets to identify current speakers.