Abstract: With the current initialization procedures defined in the VDSL and ADSL standards, even though the xDSL system could operate in Showtime in an impulse noise environment where symbols are being corrupted, the transceivers would not be able to reach Showtime because initialization would fail due to initialization message failure. Through the use of an improved initialization procedure for communication systems, operation in environments with higher levels of impulse noise is possible.

Abstract: Included are embodiments for reducing interference in a communications network. At least one embodiment of a method includes receiving data related to an updated Power Spectral Density (PSD) mask and processing a first Seamless Rate Adaptation (SRA) request. Some embodiments include processing a second Seamless Rate Adaptation request and implementing the updated Power Spectral Density mask.

Abstract: Security of photographic identification documents is enhanced by embedding within the photographic image encoded information that may be correlated to other information pertaining to the individual represented by the image, such other information being, for example, printed on the document adjacent to the photograph.

Abstract: There is disclosed technical means for effectively judging a communication quality in a communication system. A communication device generates a four-value FSK symbol by adding a redundant bit to a bit of the most important part of encoded audio data. The symbol containing the redundant bit is set so that the symbol value is the maximum value of the minimum value of the four values which may be obtained. A reception device R receives the FSK modulation wave, restores the symbol, counts the number of redundant bits contained in the restored symbol and having incorrect values, decides whether to perform a bad frame masking process and what kind of bad frame masking process is to be performed, and executes the decided process. Thus, it is possible to accurately or rapidly judge the communication quality with a simple configuration.

Abstract: Apparatus and method for measuring an SINR in a mobile communication system using preambles. Calculated are an average noise power using a CP of an RX signal, a signal power of a serving segment, an average power of the serving segment, and an interference power of the serving segment, an average power of each interference segment, and an interference power of each interference segment using the difference between the calculated average noise power and the calculated average power. An SINR of the RX signal is calculated by dividing the calculated signal power of the serving segment by the sum of the calculated average noise power and the total interference power of all the segments.

Abstract: This invention provides colored noise detection algorithm(s). This colored noise detection algorithm(s) may be implemented with a multi-branch equalizer processing module that enables interference cancellation when colored noise is associated with received radio frequency (RF) bursts. The noise discriminator identifies when the radio frequency (RF) bursts have white noise or colored noise associated with them. Alternatively the noise discriminator may be able to determine and enable interference cancellation in response to an interference-limited received RF burst as opposed to a noise-limited received RF burst. The multi-branch equalizer improves the signal-to-noise ratio by improving the equalization with a second branch operable to be trained based upon known training sequences and at least partially re-encoded data bits.

Abstract: A necessary number of initial stage element circuits, intermediate stage element circuits, and final stage element circuits are connected in cascade and combined in parallel arrangement simultaneously. The partial sum output data on the element circuits is synchronized with the inner partial sum data. In this way, it is possible to configure a high-speed high-order and high-precision FIR filter, i.e., a large-scale digital filter. Thus, it is possible to manufacture a high-order and high-precision FIR filter capable of high-speed operation of 2 GHz or above at a low cost.

Abstract: The invention relates to a transmission circuit for a transponder system used for transmitting a digital signal via a transmit antenna for radio waves having a predefined carrier frequency, e.g. to be utilized for keyless access control systems in motor vehicles. In order to be able to operate said transmission circuit across a wide range of operating voltages while keeping losses small, a PWM signal generator is provided for generating a pulse width-modulated signal having a given clock frequency which is greater, preferably by a multiple, than the frequency of the digital signal while the digital signal is superimposed on the PWM signal so as to transmit said digital signal. The PWM signal controls switched-mode semiconductor switches, a bandpass prefilter being mounted upstream of the transmit antenna. Preferably, a control circuit is provided for adjusting the pulse/pause ratio of the PWM signal and adjusting the current flowing through the transmit antenna to a setpoint value.

Abstract: Electromagnetic signals for transmitting television and other information more robustly have amplitudes modulated in accordance with a digital signal generated by convolutional interleaving and trellis coding of segments of successive data fields, each of which segments contains a prescribed number of bytes. In improvements of these signals, respective fractional portions of a Reed-Solomon forward-error-correction codeword are transmitted in respective ones of a plurality of the segments of the successive data fields. The respective ones of the plurality of segments are separated from each other within the successive data fields, such that their individual bytes do not interleave with each other after the convolutional interleaving and trellis coding are completed.

Abstract: The present invention provides an encoding method for skipped macroblocks in a video image comprising the steps of: adding one indication bit into a picture header for indicating a coding mode for skipped macroblocks in a current image; selecting the coding mode for a macroblock type in the current image according to the number of skipped macroblocks, if it is a run_length coding, then setting the indication bit of the picture header as a status indicating a run_length coding, and encoding the macroblock type in the image by the run_length coding mode; if it is a joint coding of the number of skipped macroblocks and the macroblock type, then setting the indication bit of the picture header as status indicating a joint coding and encoding the macroblock type in the image by the joint coding mode of the number of skipped macroblocks and the macroblock type; finally, encoding other data in the current macroblock and writing data into a code stream.

Abstract: A video surveillance system in which the compressed video is written to a digital tape cassette. The tape cassette includes an EEPROM, which holds directory information relating to the location of particular video on the tape, the identity of the tape, the identity of the video, and other key information relating to the video. The directory on the EEPROM permits rapid access to the video and redundancy of key data. In case of tape error, the tape automatically restores itself when inserted into the tape deck.

Abstract: An improved switched filter up-sampling mechanism for scalable video coding. A filter switching mechanism of the present invention takes advantage of the best performance of each of the filters in a collaborative manner. The switching process of the present invention can be generalized to more filter choices and potentially relieve the computational complexity due to the added freedom and flexibility of filter choices.

Abstract: Scalable video coding and multiplexing compatible with non-scalable decoders is disclosed. In some embodiments, video data is received and encoded in a manner that renders at least a base layer to be compatible with a non-scalable video encoding standard, including by assigning for at least the base layer default values to one or more scalability parameters. In some embodiments, video data is received and encoded to produce an encoded video data that includes a base layer that conforms to a non-scalable video encoding standard and one or more subordinate non-scalable layers, which subordinate non-scalable layers do not by themselves conform to the non-scalable video encoding standard but which can be combined with the base layer to produce a result that does conform to the non-scalable video encoding standard, such that the result can be decoded by a non-scalable decoder.

Abstract: When image data to be encoded is divided into image data items in a plurality of hierarchies and an image data item in a given hierarchy among the divided image data items in the plurality of hierarchies is to be encoded as an intra picture, an image encoding apparatus and an image decoding apparatus provided by the invention allow improvement in efficiency of encoding the image data item in the given hierarchy. When input image data is divided into image data items in a plurality of hierarchies for encoding and a higher hierarchy image data item is to be encoded as an intra picture, a control circuit switches a switch so that reference data is supplied to a subtracting circuit. The subtracting circuit subtracts the reference data from the higher hierarchy image data item outputted from a preprocessing circuit. Encoding is performed on the subtraction result of the subtracting circuit, i.e. differential image data.

Abstract: The invention relates to the field of data processing, for processing a stream of data comprising video data, the video data comprised in a sequence of frames. Typically, the data also comprises audio data, and optionally further multimedia data such as data relating to interactive functionality. The invention provides a method and system for playing a multimedia digital data stream comprising video data to be decoded and displayed to a user in a sequence of frames, including the steps of: receiving and decoding the video data; monitoring a decoding parameter; applying a post-processing algorithm to decoded video frames; aid displaying the resulting frames on a display device; wherein the post-processing algorithm applied is continuously adapted in accordance with said decoding parameter.

Abstract: A method of encoding video data using soft decision quantization makes use of iterative encoding to provide the ability to optimize encoding across different functional elements in a hybrid video encoder. Iterative encoding is used to allow quantization step size, motion prediction and quantization levels to be optimized despite their interrelated nature.

Abstract: A video coding apparatus carries out a compression coding of a video based on a result of predicting a motion vector predicted between frames of the video. A quantization parameter control unit comprised of the apparatus calculates a ratio of an accumulation value, in the small block, of a prediction error of a brightness component to an accumulation value, in the small block, of a prediction error of a color difference component at the time that a motion vector detection/compensation unit which carries out a motion compensation based on a prediction result of the motion vector for the small block designated in a frame of the above video as a prediction accuracy indicator of the foregoing motion vector, and carries out a control of a quantization unit executing a quantization of image information of the small block based on the prediction accuracy indicator.

Abstract: The apparatus includes: orthogonal transforming means for orthogonally transforming an input video signal for each element block, quantizing means for quantizing each obtained transformation coefficient using a quantization parameter; coding means for coding the quantization parameter; decoded picture generating means for generating a reference picture signal for a motion compensation prediction from the quantized results of the quantizing means; filtering means for filtering the obtained reference picture signal at a strength corresponding to the quantization parameter when a non-zero effective transformation coefficient is present with respect to the element block; and controlling means for controlling at least anyone of transformation coefficients to be not zero, when all of the transformation coefficients are zero.

Abstract: A method and apparatus for blending a video signal responsive to a chroma motion result is disclosed. The method and apparatus are configured to determine whether any chroma motion exists within the video signal and providing the chroma motion result, to provide a first blending signal based on the chroma motion result; to provide a second blending signal based on the chroma motion result; to modulate temporal filtered luma and chroma components of the video signal with the first blending signal, to modulate spatial filtered luma and chroma components of the video signal with the second blending signal, and to add the modulated temporal luma and chroma signals to the modulated spatial luma and chroma signals to provide a blended video signal.

Abstract: The present invention provides a video coding method which includes, as one of a plurality of coding modes, a direct mode generating a piece of motion information of each of Macro Blocks, which are obtained by dividing a first picture, by predicting from motion information of a coded Macro Block of other plurality of second pictures, including: a first step for selecting the direct mode as the coding mode by using a variable selection criterion; and a second step for coding the Macro Blocks based on the selected coding mode.

Abstract: A method and system for performing motion estimation for a frame associated with a video signal. The method includes receiving at least a reference frame, a first frame, and a second frame, and providing a first plurality of vectors. The first plurality of vectors intersects the first frame within a first block and intersects the reference frame within a first plurality of blocks respectively. Additionally, the method includes determining a second plurality of vectors based on at least information associated with the first plurality of vectors. The second plurality of vectors intersects the second frame within a second block and intersecting the reference frame at a plurality of locations. Moreover, the method includes processing information associated with the plurality of locations, and determining a plurality of search areas corresponding to the plurality of locations in the second frame.

Abstract: For encoding of a picture whose macroblock is divided into parts of various sizes, a picture encoding method is provided to appropriately reduce a coding amount of a motion vector, without lowering coding efficiency. In order to reduce a processing amount and an increase of a coding amount, which result from generation of a large number of motion vectors due to bi-directional prediction selected for a small-sized part, a motion estimation unit (112) selects the optimal prediction method from prediction method candidates decided by a prediction-method-candidate determination unit (13). Thereby, when motion compensation is performed for a large-sized part, forward-directional, backward-directional, and bi-directional prediction can be permitted. On the other hand when motion compensation is performed for a small-sized part, the bi-directional prediction is prohibited but the forward-directional or backward-directional prediction is permitted.

Abstract: The method implements an update step which is a selection among at least the following coding modes: a default coding mode which doesn't use the motion compensation for the calculation of the pixel if the pixel is not connected or which performs a low pass motion compensated temporal filtering of picture H of same level if the pixel is connected, an update_MV coding mode which performs a low pass motion compensated temporal filtering of picture H of same level according to a default motion vector calculated by taking into account motion vectors belonging to regions or pixels in the vicinity of the pixel to be calculated. Applications relate to video compression for transmission or storage of data.

Abstract: Some embodiments of the invention provide a method of performing motion estimation for an array of image values obtained from a current image. The method starts with an initial estimate of the motion of the current image. The method then determines whether the initial estimate of the motion of the current image array between the current image and a reference image is acceptable. If not, the method specifies a first value for a parameter for performing the motion estimation. Otherwise, the method specifies a second value for the parameter. The method then performs a motion estimation operation based on the specified value of the parameter. One example of a specified parameter is the size of the window that the motion estimation operation uses. Another example is the starting level for a hierarchical motion estimation operation that it performs. A hierarchical motion estimation operation searches the reference frame at several different levels of granularity.

Abstract: A method for determining a search pattern for use in fractional motion estimation for video compression includes selecting a search center within a current macroblock; selecting a plurality of search points forming a half-pel search pattern surrounding the search center, and further selecting another search point at the search center; calculating a cost value for each search point according to a first cost function; and selecting a quarter-pel search pattern according to the cost values of at least two search points, the half-pel search pattern and the quarter-pel search pattern forming the search pattern. The search pattern is used in a matching process to determine a similarity of the current macroblock to a reference macroblock in a video undergoing compression.

Abstract: A method of half-pixel interpolation and quarter-pixel interpolation are adapted for reducing the impact of aliasing within motion estimation. To estimate a motion vector with quarter-pixel accuracy more efficiently, the improved method is able to skip checking certain points using the uni-modal assumption. In an embodiment, a diamond based refinement is implemented. Within the diamond based refinement are half-pel refinement and quarter-pel refinements. Furthermore, within the half-pel refinement are methods for on-the-fly interpolation and pre-computed interpolation. Within quarter-pel refinement, the method depends on whether four neighbor half-pel points are checked or just one or two half-pel points. Moreover, within each of the different embodiments is the ability to focus on quality or speed wherein different methods are implemented to maximize the desired function. In another embodiment, a square based refinement is implemented.

Abstract: An apparatus (40) for determining motion between a first and second video image comprising means for receiving a first video image comprising a plurality of pixels, means for selecting a block of pixels within the first video image (48), means for receiving a second video image comprising a plurality of pixels, means for selecting at least part of the second video image to produce a search area (47), means for sampling the pixels of the search area in a predetermined pattern and means for comparing the selected block of pixels within the first video image with at least one block of the sampled pixels of the search area to determine the motion of the block of pixels between the images (44) wherein the pattern of sampled pixels varies throughout the search area.

Abstract: A video and graphics system processes video data including both analog video, e.g., NTSC/PAL/SECAM/S-video, and digital video, e.g., MPEG-2 video in SDTV or HDTV format. The video and graphics system includes a video decoder, which is capable of concurrently decoding multiple SLICEs of MPEG-2 video data. The video decoder includes multiple row decoding engines for decoding the MPEG-2 video data. Each row decoding engine concurrently decodes two or more rows of the MPEG-2 video data. The row decoding engines have a pipelined architecture for concurrently decoding multiple rows of MPEG-2 video data. The video decoder may be integrated on an integrated circuit chip with other video and graphics system components such as transport processors for receiving one or more compressed data streams and for extracting video data, and a video compositor for blending processed video data with graphics.

Abstract: A data storage unit (103) stores an image frame in which an image frame which consists of coded data having a data loss or error received by a receiving unit (100) and complementary coded data which is received by receiving unit at a later time are rearranged into normal sequence. A redecoding unit (105) decodes the image frame stored in the data storage unit (103) with reference to one or more already-decoded image frames required for the decoding, and stores the decoded image frame in a frame additionally-storage unit (104). A decoding unit (101) decodes an image frame with reference to an image frame stored in either a frame storage unit (102) or the frame additionally-storage unit 104 according to a command from a control unit (106).

Abstract: An apparatus for post-processing a video image may include a filter configured to remove artifacts from pictures decoded by a video decoder; a differential picture encoder configured to produce compressed differential pictures based on the decoded pictures and the pictures filtered by the filter; and a differential picture decoder configured to reconstruct the filtered pictures based on the decoded pictures and the compressed differential pictures. A method for post-processing a video image may include filtering pictures decoded by a video decoder to remove artifacts from the decoded pictures; producing compressed differential pictures based on the decoded pictures and the filtered pictures; and reconstructing the filtered pictures based on the decoded pictures and the compressed differential pictures. A video image system may include a video decoder; a filter; a differential picture encoder; a memory; a differential picture decoder; and a display unit.

Abstract: A relay unit capable of avoiding the occurrence of simultaneous switching whatever data is received and thereby preventing malfunction of the device due to impulse noise, and a memory product having stored therein a computer program are provided. The relay unit includes a latch unit that temporarily stores converted parallel data; a determining unit that compares received data with subsequent data to be received subsequently and thereby determines whether to invert bits of data; and an inverting unit that invert bits of converted serial data. When the determining unit determines that bit-inverted parallel data is received as subsequent data, the determining unit transmits to the latch unit a signal instructing to prohibit from storing temporarily the received subsequent data and transmits to the inverting unit a signal instructing to invert bits of data.

Abstract: Code designs for channel coding with side information (CCSI) based on combined source-channel coding are disclosed. These code designs combine trellis-coded quantization (TCQ) with irregular repeat accumulate (IRA) codes. The EXIT chart technique is used for IRA channel code design (and especially for capacity-approaching IRA channel code design). We emphasize the role of strong source coding and endeavor to achieve as much granular gain as possible by using TCQ. These code designs synergistically combine TCQ with IRA codes. By bringing together TCQ and EXIT chart-based IRA code designs, we are able to approach the theoretical limit of dirty-paper coding.

Abstract: Multiscale communication, wherein time-frequency conditioning off the transmitted signal is used, is examined with respect to typical wireless communications systems, in which the modulating wavelet is matched to a specific channel condition. Compactly supported wavelet bases are employed, and based on their parameterization a wavelet is selected that best characterizes the wireless channel conditions.

Abstract: A frame timing synchronization technique for orthogonal frequency division multiplexing (OFDM) systems is presented. First, a coarse synchronization technique generates a coarse frame timing estimate. The coarse synchronization technique applies a sliding window differentiator to the output of a conventional auto-correlator to mitigate the plateau effect associated with conventional auto-correlation techniques. Second, a fine synchronization technique generates a fine frame timing estimate. The fine synchronization technique uses the coarse frame timing estimate to reduce the number of cross-correlation calculations. Additionally, the fine synchronization technique acquires a fine frame timing estimate based on a signal-to-interference ratio (SIR) metric, which is more robust to multi-paths and pseudo multi-paths caused by cyclic delay diversity (CDD) schemes than conventional cross-correlation synchronization techniques.

Abstract: A frequency tracking method and apparatus is provided. A receiver receives OFDM symbols and determines associated frequency offset. A frequency error estimator selects a cross correlation window for determining frequency offset based on timing offset. A symbol timing estimator is used to determine the timing offset.

Abstract: An apparatus and a method can improve the performance of a smart antenna system for signal processing in the frequency domain. The method includes: performing Fast Fourier Transform (FFT) on a plurality of incoming signals received through antennas according to a predetermined FFT window; detecting a boundary of an OFDM symbol and setting the FFT window with a margin as large as a predetermined FFT window offset with reference to the detected symbol boundary; receiving the FFT window offset and generating an FFT window calibration signal; and multiplying the FFT-processed incoming signals by the FFT window calibration signal. The method can improve the reception performance of a base station by compensating for the multi-path channel by using an RX FEQ coefficient obtained by a receiver of a terminal as an FEQ weight of a transmitter of the terminal. Further, the method can generate a uniform non-directional beam by generating a variable omni-directional beam pattern in a smart antenna system.

Abstract: A method and system for determining channel response is provided. The method for determining a channel frequency response (CFR) in a block transmission system comprises performing an N? point Fast Fourier Transformation (FFT), where N? is a function of N and K, and N is approximately equal to the number of sub-carriers in a block, and K depends on the coherence bandwidth of the channel corresponding to the block.

Abstract: A radio transmission device capable of improving the reception error rate characteristics of a receiver. In this device, an FFT (Fast Fourier Transform) unit (102) subjects a transmission signal to an FFT operation, in which a signal in a time domain is converted into a signal in a frequency domain. A control unit (103) controls the transmission power of the FFT-operated transmission signal in the frequency domain. An IFFT (Inverse Fast Fourier Transform) unit (104) subjects the transmission signal having its transmission power controlled, to an IFFT operation, in which an inverse conversion is made into a signal in the time domain. A transmission RF unit (106) transmits the IFFT-operated transmission signal on a single carrier.

Abstract: An uplink signal receiving method and apparatus using successive interference cancellation (SIC) in a wireless transmission system based on Orthogonal Frequency Division Multiple Access (OFDMA) are provided.

Abstract: A method and apparatus for performing channel estimation using time-frequency localized pilots and de-noising techniques are disclosed. A transmitter sends pilot symbols which are localized in a joint time-frequency domain to a receiver for channel estimation. The receiver receives the pilot symbols and performs a time-frequency analysis, such as a discrete Gabor transform (DGT), to transform the received pilot symbols to a joint time-frequency domain. The receiver applies a de-noising technique, such as masking, to separate the pilot symbols from the embedded noise in the joint time-frequency domain. The receiver performs a time-frequency synthesis, such as an inverse discrete Gabor transform (IDGT), to generate a noise-removed pilot symbols in a time domain. The noise left after de-noising is only that part that overlaps with the pilot symbols in the joint time-frequency domain. The receiver then performs channel estimation with the noise-removed pilot symbols.

Abstract: A method for transmitting control signals in a multi-carrier system. A method for arranging pilots in a transmitting side which transmits and receives data using a plurality of sub-carriers includes acquiring transmission data to be transmitted to a receiving side, processing data of a specific region among the transmission data in accordance with hidden pilots for channel estimation of the receiving side, allocating specific radio resources exclusively for the transmission data and dedicated pilots for channel estimation of the receiving side.

Abstract: Provided are an apparatus and a method for acquiring frame synchronization in a broadband wireless communication system using a plurality of preamble sub-carrier patterns. The apparatus includes a plurality of preamble detectors that perform phase compensation on input sample data in accordance with a corresponding pattern and computes correlation values for respective time indices by using the phase-compensated sample data; an adder that sums the correlation values received from the preamble detectors; and a synchronization determination unit that compares sums obtained from the adder so as to select a maximum value and determines a time index corresponding to the maximum value as the frame synchronization.

Abstract: An apparatus and method for channel estimation in a wireless communication system are provided, in which a first channel estimate is calculated using a pilot signal included in a received signal, a data signal included in the received signal is demodulated using the first channel estimate, a second channel estimate is calculated using the demodulated data signal, the first channel estimate is corrected using the second channel estimate and the data signal is demodulated using the corrected first channel estimate.

Abstract: A system comprises a correlation module that correlates modulated signals with a plurality of preamble sequences and that generates correlation values. A control module selects a largest correlation value from said correlation values and detects one of said preamble sequences in said modulated signals upon determining that a magnitude of said largest correlation value is greater than or equal to a first predetermined threshold.

Abstract: In an OFDM receiver, one of a plurality of antennas is selected based on a ratio X of two moving average integration values (first moving average integration value and second moving average integration value) that are calculated from a non-delay symbol and a delay symbol. It could be said that the second moving average integration value represents excessive false information (that is, whether the state of the transmission line is good). Accordingly, determination of the ratio X between the second moving average integration value and the first moving average integration value and selection of one of the plurality of antennas based on the ratio X enables judgment on whether the state of the transmission line is good even during a period other than a guard interval period Tg, that is, during an effective symbol period Tu.

Abstract: A likelihood metric calculation method including: estimating a channel of a received signal and generating a channel estimate; compensating a channel of the received signal according to the channel estimate; calculating a region variable according to the channel estimate; and comparing the region variable and a magnitude of the compensated received signal and calculating a likelihood metric of the received signal according to a result of the comparison.

Abstract: A lattice space time coding arrangement for transmission systems is disclosed which enables construction of lattice space time codes with improved error rate performance for arbitrary receiver structures.

Abstract: Embodiments include systems and methods for improving performance of multiple spatial communications channels. Embodiments comprise power loading a steering matrix to achieve improved performance.

Abstract: A method of feeding back channel information in an OFDM or OFDMA radio communications system is disclosed, in which a transmitting side instructs a region for measuring a downlink channel status and in which a receiving side feeds back the channel information to the transmitting side. The present invention includes the steps of transmitting instruction information instructing at least one region of at least two regions within a data frame as a signal measurement region to a receiving side and receiving the channel information estimated by a signal included in the signal measurement region instructed by the instruction information from the receiving side.

Abstract: The present invention provides a receiver. In one embodiment, the receiver includes a receive portion employing transmission signals from a transmitter having multiple antennas and capable of providing channel estimates. The receiver also includes a feedback generator portion configured to provide to the transmitter a pre-coder selection for data transmission that is based on the channel estimates, wherein the pre-coder selection corresponds to a grouping of frequency-domain resource blocks. The present invention also provides a transmitter having multiple antennas. In one embodiment, the transmitter includes a transmit portion coupled to the multiple antennas and capable of applying pre-coding to a data transmission for a receiver. The transmitter also includes a feedback decoding portion configured to decode a pre-coder selection for the data transmission that is fed back from the receiver, wherein the pre-coder selection corresponds to a grouping of frequency-domain resource blocks.