Abstract: Provided is an apparatus and method for detecting a time-frequency code in an MB-OFDM UWB system. The apparatus includes a controller for providing a band selection signal to the RF receiver and outputting a preamble selection signal at regular symbol periods to calculate a cross correlation value for a predetermined time period more than a beacon frame interval when a time-frequency code search start signal is received; and a cross correlator for storing information on preamble patterns, selecting a preamble stored depending on the preamble selection signal, and calculating a cross correlation value for a digital signal transferred through the RF receiver, wherein the controller determines a time-frequency code using a preamble where a peak occurs as a time-frequency code that is currently in use when a peak signal is inputted based on the calculated cross correlation value, and transmits the determined time-frequency code to the MAC receiver.

Abstract: ej(2n?/N) calculating section 101 generates a bth chip C(a,b) of an ath spreading code based on C(a,b)=ej(2n?/N) where e is a base of natural logarithm and N is a length of the spreading code (i.e. spreading code length). It is assumed in the above equation that n=a×b, a=0˜N?1, and b=0˜N?1. It is thereby possible to generate orthogonal spreading codes with arbitrary lengths.

Abstract: A direct-sequence spread-spectrum communications method of de-spreading and decoding received data transmitted through an acoustic channel. A first code match filter is applied to receive data to output a first code impulse response comprising a channel impulse response modulated by a pseudo-random number bit. A second code match filter is applied to the received data to output a second code impulse response comprising the channel impulse response modulated by a message symbol bit. The first code impulse response is correlated with the second code impulse response to output the message symbol bit modulated by the pseudo-random number bit. The pseudo-random number bit is eliminated to identify the message symbol bit, thereby decoding the message symbol bit from the received data.

Abstract: One embodiment of the present invention relates to a method of transferring data in a communication system. In the method, an initial impulse noise protection value is determined. A number of redundancy bits is added to blocks of data to form codewords as a function of the initial impulse noise protection value, where the impulse noise protection value corresponds to a number of consecutive symbols that can be corrected. The number of symbols that can be correctly transmitted is changed by changing only the number of redundancy bits added to each block of data.

Abstract: Nonlinearity characterization that transmits bursts of information where symbols vary by a value Delta. The bursts can be bursts of a constant power, followed by another burst of a different constant power. An alternative burst system uses interleaved power symbols, where some symbols in a single burst are at the first power and others are at the second power. The signal-to-noise ratio of the two groups of symbols is estimated, and the difference is used to determine whether or not to reduce the amount of saturation in the transmitter.

Abstract: A method of analyzing a digital video clip to determine candidate frames for subsequent key frame selection, includes: performing a global motion estimate on the video clip that indicates translation of a scene or camera, or scaling of the scene; and forming a plurality of video segments based on the global motion estimate and labeling each segment in accordance with a predetermined series of camera motion classes. The method further includes extracting key frame candidates from the labeled segments and computing a confidence score for each candidate by using rules corresponding to each camera motion class and a rule corresponding to object motion.

Abstract: A digital broadcast system is disclosed. The digital broadcast system including a transmitter, a receiver, and a method for transmitting and receiving a DTV signal comprising main service data and mobile service data multiplexed with the main service data. The DTV signal results from generating a second data by de-interleaving a first data group by a DTV transmitter.

Abstract: Techniques for detecting and mitigating intermodulation distortion (IMD) are described. A device (e.g., a cellular phone) obtains digital intermodulation distortion and digitally determines intermodulation distortion in an input signal based on the digital intermodulation distortion. The device may correlate the digital intermodulation distortion with the input signal and determine intermodulation distortion in the input signal based on correlation results. The device may adjust the operation of one or more circuit blocks (e.g., a mixer, an LNA, etc.) in a receiver based on the detected intermodulation distortion in the input signal. Alternatively or additionally, the device may condition the digital intermodulation distortion to obtain conditioned intermodulation distortion matching intermodulation distortion in the input signal and may then subtract the conditioned intermodulation distortion from the input signal.

Abstract: A data receiving apparatus which makes it possible to obtain reliable received data during EOP period and a preceding period, and which makes it possible to receive serial data in a reliable manner. Data receiving apparatus 100 is provided with receiving comparator 102 which has first signal line 101a and second signal line 101b for differential input; NOR circuit 105 that outputs a logical output, as a trigger signal, at the time the first signal and the second signal have changed from out-of-phase to in-phase; and D-FF circuit 107 that retrieves, by means of a trigger signal from NOR circuit 105, and holds an output RCV of receiving comparator 102; wherein selection circuit 108 selects the output of receiving comparator 102, when the first signal of first signal line 101a and the second signal of second signal line 101b are out-of-phase with each other, and outputs, as received data, a value held in D-FF circuit, when the first signal and the second signal have changed from out-of-phase to in-phase.

Abstract: In a multivalue modulation type with one pilot symbol inserted for every 3 or more symbols, signal points of each one symbol immediately before and after a pilot symbol are modulated using a modulation type different from that for pilot symbols. In this way, it is possible to suppress deterioration of the accuracy in estimating the reference phase and amount of frequency offset by pilot symbols and improve the bit error rate characteristic in the signal to noise ratio in quasi-coherent detection with symbols whose symbol synchronization is not completely established.

Abstract: A preamble acquisition apparatus includes a first PN code generation unit for generating a first PN code having a bit string, a first correlation calculation unit for correlating a received frequency domain preamble signal with the first PN code within a first correlation range to generate a first correlation value, a first correlation value comparison unit for comparing the first correlation value with a first threshold value, a second PN code generation unit for generating a second PN code, a second correlation calculation unit for correlating the received frequency domain preamble signal with the second PN code within a second correlation range to generate a second correlation value, and a preamble acquisition determination unit for comparing the second correlation value with a second threshold value to determine whether to acquire the preamble. The bit values of the first PN code are located in the second PN code.

Abstract: A transmission mode/guard length detection circuit that uses the Orthogonal Frequency Division Multiplexing method, in which: a difference between a reference wave having a constant period generated on the basis of a transmission mode length that is a time period length of the predetermined symbol and a guard length that is a time period length of the guard interval and the peak value interval is calculated as a shift amount, and the shift amount is integrated for a symbol and is output, and the result of the integration for a predetermined symbol is changed on the basis of the shift amount.

Abstract: The present invention provides a video encoding device in which a capacity of a binary data storing unit is small, a size of the video encoding device is small, a video signal can be processed in real time, and reduction in quality of images generated from the eventually obtained data can be prevented. The video encoding device according to the present invention includes: a video encoding unit which encodes a video signal; a binarization unit which binarizes an encoded value obtained from the video encoding unit; and an entropy encoding unit which subjects entropy encoding to binary data obtained from the binarization unit.

Abstract: The method and circuit provide an effective implementation to handle the data transferring problem between multiple clock domains. A shift circuit shifts the incoming data stream, which comprises N parallel signals divided into a first group of parallel signals and a second group of parallel signals, to be in accordance with a first sequence of N sampling pulses, and a sampling module sequentially samples each signal in the first group signals and the second group signals with the N sampling pulses in a second sequence and outputs a serial signal.

Abstract: Communication device for processing outgoing and incoming packets. The device includes a plurality of signal processing units connected in sequence, each signal processing unit being clocked by a common clock signal. The device further includes a mode line connected to each signal processing unit for switching each signal processing unit between a transmit mode and a receive mode. The device further includes a control line to which each signal processing unit is connected. The control line communicating flow control information either in the transmit mode to at least one of the preceding signal processing units or in the receive mode to at least one of the following signal processing units.

Abstract: Spectrum-sensing algorithms and methods may be provided for use in cognitive radios and other applications. The spectrum-sensing algorithms and methods may include receiving an input spectrum having a plurality of channels, performing a coarse scan of the plurality of channels of the input spectrum to determine one or more occupied candidate channels and vacant candidate channels, where the coarse scan is associated with a first resolution bandwidth and a first frequency sweep increment, performing a fine scan of the occupied candidate channels and the vacant candidate channels to determine actually occupied channels and actually vacant channels, where the fine scan is associated with a second resolution bandwidth and a second frequency sweep increment, and storing an indication of the actually occupied channels and the actually vacant channels.

Abstract: Joint decoding of ISI (Inter-Symbol Interference) channel and modulation codes. A single, combined ISI and modulation decoding module is operable to process a signal received from an ISI communication channel and directly to generate a soft estimate of information encoded therein. A single module employs a decoding transfer function that is substantially matched to the communication channel that introduces the ISI and the modulation encoding performed on the information before being launched into the ISI communication channel. Such operations and functionality are adaptable to a variety of modulation coding systems that are tailored to deal with communication systems that introduce ISI. Moreover, such operations and functionality are extendable to communication systems employing an error correction code (ECC) such as Reed-Solomon (RS) coding as well as ECCs of an iterative nature such as LDPC (Low Density Parity Check) coding, turbo coding, and/or turbo trellis code modulation (TTCM) coding.

Abstract: A method includes receiving at least two space-time coded signals from an antenna system associated with a first station, determining complex channel state information based on the received space-time coded signals, and sending the complex channel state information to the first station. In an alternative embodiment, a method includes transmitting at least two space-time coded signals in respective beams of a multi-beam antenna array, measuring a channel impulse response for each space-time coded signal at a second station, and sending an indicia of a selected set of least attenuated signals from the second station to the first station. The multi-beam antenna array is associated with a first station. The beams transmit a signature code embedded in each respective space-time coded signal, and the signature codes are orthogonal so that the second station can separate and measure the channel impulse response corresponding to each space-time coded signal.

Abstract: A receiver of a CDMA system, receiving a signal transmitted through a multi-path channel, with a path alignment circuit is disclosed. The path alignment circuit has a pack-based memory device serially inputting samples of low over-sampling rate than that required by the CDMA system and outputting data packs pack by pack to reduce access rate of the memory device. In addition, the path alignment circuit has an interpolation device which reads the data packs from the memory device and performs interpolation to raise the resolution of the low over-sampling samples and generate interpolated samples of high resolution for de-spreading requirement of the CDMA system.

Abstract: Spread spectrum transmission of information is performed using chaotic signals. Direct chaotic communication systems in which information is input to chaotic signal generated directly in information transmission frequency band, are achieved by forming broadband information carrier necessary for transmission and using a chaotic dynamic system whose structure is synthesized in advance in accordance with predetermined characteristics of broadband information carrier to cause chaotic dynamic system to provide operation of forming the broadband information carrier in form of a chaotic information carrier having prescribed spectral characteristics.