Patent application number | Description | Published |
20080273585 | Apparatus for Estimating Phase Error and Phase Error Correction System Using the Same - Provided are an apparatus for estimating a phase error and a phase error correcting system using the phase error estimating apparatus. The apparatus includes: a probability value estimating unit for estimating a negative log probability value for each transmission symbol by transforming a soft output information transferred from the outside to a log A posterior probability ratio (LAPPR) value; an APP value calculating unit for calculating a posterior probability (APP) value by applying a negative exponential function to the transmission symbol; an average value deciding unit for deciding an average value for each transmission symbol using the probability information entirely, partially, or selectively according to a probability information type; and a symbol phase estimating unit for estimating a phase of a symbol based on the decided average value. | 11-06-2008 |
20080285591 | Apparatus and Method for Deciding Transmission Format Using Variable Frame Length and Decoding Method Using the Same - Provided are an apparatus and method for deciding a transmission format using a variable frame length and a decoding method using the same. The apparatus for deciding the transmission format using the variable frame length includes: a frame synchronization acquiring unit for acquiring a frame synchronization of a received transmission frame; a correlation analyzing unit for performing a correlation analysis with respect to the transmission frame whose synchronization is acquired, considering frame lengths of respective frame structures; and a transmission frame structure deciding unit for deciding the structure of the received transmission frame using the analyzed correlation. Accordingly, a physical layer signaling code (PLSC) demodulation and decoding performance can be enhanced by determining the structure of the transmitted frame without carrying out a PLSC decoding in such a state that a frequency synchronization is not acquired. | 11-20-2008 |
20080310560 | Apparatus for Estimating Phase Offset of Multiple Survival Paths and Digital Wired/Wireless Communication System Using the Same - Provided is an apparatus for estimating phase offsets of multiple survival paths and a satellite communication system using the same. The apparatus includes: upper/lower decoding units for obtaining a phase offset estimation value and estimating phase offsets of each survival path based on a stored parameter estimation value of a previous state inputted from an external device; an interleaving/de-interleaving unit for minimizing correlation between data used to estimate a parameter according to the estimated phase offset value from the upper/lower decoding means; and a phase offset outputting unit for outputting the phase offset value estimated through the upper decoding unit and the de-interleaving unit. | 12-18-2008 |
20100007743 | FRAME SYNCHRONIZATION AND STRUCTURE DETECTION METHOD IN DVB-S2 SYSTEM - Provided is a method for detecting frame sync and frame structure in a satellite broadcasting system. The method for detecting frame sync and frame structure includes the steps of: calculating differential correlation values of reception symbols; generating index sequences of reception symbols whose differential correlation values calculated above exceed a threshold value; calculating positions estimated as frame start points which correspond to a total frame number based on the number of symbols per frame for each frame structure; and detecting frame sync and frame structure based on the umber of positions where the above-calculated frame start point estimated positions and the above-generated index sequences are matched. | 01-14-2010 |
20100322366 | METHOD FOR DETECTING FRAME SYNCHRONIZATION AND STRUCTURE IN DVB-S2 SYSTEM - Provided is a method for detecting frame sync and frame structure in a satellite broadcasting system, which acquires an estimated value for detecting frame structure and frame sync and overcomes distortion of correlation analysis values by summing differential correlation values for SOF positions in consideration of the variable frame length, and selecting a maximum value in a channel environment with low signal-to-noise ratio and high frequency error. SOF is a sync word indicating the start point of a frame. The method includes the steps of: acquiring SOF differential correlation value sequences; acquiring sums (d | 12-23-2010 |
Patent application number | Description | Published |
20100046415 | METHOD AND SYSTEM FOR EFFECTIVE ADAPTIVE CODING AND MODULATION IN SATELLITE COMMUNICATION SYSTEM - A Second Generation Digital Video Broadcasting via Satellite (DVB-S2) system is provided. More particularly, a method and apparatus for maintaining synchronization of a signal by changing an Adaptive Coding and Modulation (ACM) method that is used for a conventional DVB-S2 system are provided. In the apparatus and method, an FEC frame of a variable length is formed by turbo encoding rather than Bose-Chaudhuri-Hocquenghem (BCH) and Low Density Parity Check (LDPC) encoding, and a Physical Layer (PL) frame of a specific length is formed regardless of a modulation method, so that a satellite terminal receives a signal transmitted at a specific length regardless of a modulation method or a coding rate to easily maintain synchronization without interruption and efficiently transmit the signal. | 02-25-2010 |
20100158091 | FREQUENCY ERROR ESTIMATOR AND FREQUENCY ERROR ESTIMATING METHOD THEREOF - Provided is a frequency error estimating method of a communication system. The method includes receiving a frame, and calculating a frequency error from a SOF field of the received frame. | 06-24-2010 |
20100316161 | METHOD AND APPARATUS FOR TRANSMITTING/RECEIVING DATA USING SATELLITE CHANNEL - A method for transmitting data using a satellite channel includes: channel-encoding bit data using an e-BCH code; interleaving the encoded data; modulating the interleaved data according to a CPM scheme using four symbols; and transmitting the modulated data to a hub station. | 12-16-2010 |
20110113302 | TERMINAL TRANSMISSION APPARATUS FOR PROVIDING MULTIMEDIA SERVICE VIA SATELLITE COMMUNICATION LINK AND METHOD FOR PROVIDING MULTIMEDIA SERVICE USING THE SAME - The present invention separates inputted triple play IP data into Internet and TV data and voice (VoIP) data, encodes the Internet and TV data permitting a long delay time according to the existing DVB-S2 standard, and encodes the voice data permitting only a short delay time according to a DVB-RCS+M standard based 4K mode. Each encoded data is subjected to the orthogonal modulation and the orthogonally modulated voice data is subjected to a direct sequence spectrum spread according to a spreading factor. The spread spectrum signal is multiplexed in a SCPC frequency division multiple access (FDMA) scheme so as to overlap with frequencies allocated to each user. | 05-12-2011 |
20110150123 | TRANSMITTER, RECEIVER, TRANSMITTING METHOD, AND RECEIVING METHOD FOR COMMUNICATION SYSTEM - The present invention relates to a transmitting method, a receiving method, a transmitter, and a receiver of a communication system. A transmitting method according to an aspect of the present invention includes generating a burst by scattering a plurality of pilot symbols, and transmitting the burst. | 06-23-2011 |
20110150143 | SOFT-DECISION DEMAPPING METHOD FOR DIGITAL SIGNAL - Disclosed is a demapping method of a soft-decision of an efficient soft determining scheme which is applicable to a DVB-2 satellite communication system. The soft-decision demapping method for a digital signal received through a transmission channel in a communication system using a phase shift keying (PSK) scheme includes: selecting reference symbols in an area having a higher probability than a predetermined probability that the received signal will be positioned among all reference symbols on a constellation diagram using a most significant bit (MSB) value of the received signal; and acquiring a maximum value of a log likelihood ratio (LLR) for the selected reference symbols. | 06-23-2011 |
20110151777 | DUAL MODE SATELLITE VERY SMALL APERTURE TERMINAL APPARATUS AND CONTROLLING METHOD THEREOF - Provided are a satellite VSAT apparatus and a control method thereof. The satellite VSAT apparatus according to an exemplary embodiment of the present invention can switch a modulation type of a signal to be transmitted from an indoor unit (IDU) to the outdoor unit to a linear or non-linear type in a case in which outputting of a transmitted signal is not controlled to an outdoor unit due to limitations, that is, there is no function such as an automatic signal level control in a block up-converter (BUC), a case in which transmission output limitation is large due to a lot of interference requirements for an adjacent channel, a case in which the number of adjacent channels (carriers) is large, or a case in which adjacent channel interference is large due to a frequency in a satellite multi-beam environment and polarization reuse, in a satellite VSAT apparatus system which aims at a low-priced user terminal. | 06-23-2011 |
20130156136 | APPARATUS AND METHOD FOR ITERATIVE DETECTION AND DECODING IN WIRELESS COMMUNICATION SYSTEM - Provided is an apparatus and method for iteratively detecting and decoding a received signal in a wireless communication system. An apparatus for iterative detection and decoding (IDD) in a wireless communication system may determine a predetermined group to be updated in a first soft decision sequence, may transmit detection control information of the determined group, and may generate a second soft decision sequence based on a detection operation result of a predetermined received signal portion that is extracted based on the detection control information. | 06-20-2013 |
20130195148 | MODULATION AND DEMODULATION METHOD FOR SATELLITE COMMUNICATION USING WIDESPREAD SIGNAL-TO-NOISE RATIO (SNR) - Provided are a modulation method and a demodulation method for satellite communication using a widespread signal-to-noise ratio (SNR), the method including: adding a dummy frame to a broadcasting/communication signal frame for signal transmission of a digital video broadcasting-satellite second generation (DVB-S2) modulator; verifying a spreading factor; adding the same physical layer header to the broadcasting/communication signal frame to which the dummy frame is added, repeatedly the number of times corresponding to the verified spreading factor; and repeating the same data, for example, PL frame data as the physical layer header. | 08-01-2013 |
20140082675 | DIGITAL VIDEO BROADCASTING - SATELLITE - SECOND GENERATION (DVB-S2) BASED TRANSMISSION AND RECEPTION APPARATUS AND METHOD OPERABLE IN CIRCUMSTANCES OF LOW SIGNAL TO NOISE RATIO (SNR) - Provided is a digital video broadcasting-satellite-second generation (DVB-S2) based transmission and reception apparatus and method operable in circumstances of a low signal to noise ratio (SNR), the DVB-S2 based transmission and reception apparatus including a DVB-S2 based transmitter, a mapping unit to determine bit mapping based on at least one of a state of a transmission channel and an area to be applied, and a physical layer frame (PLframe) replica processing unit to repeat a PLframe in which a physical layer header (PLheader) corresponding to a spreading factor (SF) is inserted. | 03-20-2014 |
20150061909 | SYSTEM AND METHOD FOR SYNCHRONIZATION BETWEEN DIGITAL-TO-ANALOG CONVERTERS (DACs) FOR HIGH SPEED SIGNAL PROCESSING - Provided is a system and method for synchronization between digital-to-analog converters (DAC) for high speed signal processing. A synchronization method of a multi-DAC apparatus may include: inputting a clock to a multiplexer (MUX) DAC; dividing the clock into a first clock and a second clock; transferring a phase difference between the first clock and the second clock to a D flip-flop; and synchronizing the first clock and the second clock by processing the phase difference. | 03-05-2015 |
Patent application number | Description | Published |
20100118920 | SATELLITE COMMUNICATION TRANSMITTER AND RECEIVER FOR REDUCING CHANNEL INTERFERENCE - Satellite communication transmitter and receiver in a DVB-S2 system are provided. The satellite communication transmitter includes a modulator to modulate a satellite communication signal to be transmitted, and a spread spectrum unit to spread the modulated signal and transmit the spread signal. Accordingly, it is possible to reduce interference with a neighboring channel. | 05-13-2010 |
20100128821 | SIGNAL DEMODULATION METHOD BASED ON DVB-S2 - A satellite broadcasting frame signal demodulation method is disclosed. A demodulation method of a demodulator that demodulates a Digital Video Broadcasting-Satellite—Second Generation (DVB-S2) standard satellite broadcasting frame signal includes: performing symbol synchronization; performing frame synchronization after symbol synchronization; recovering a carrier wave after frame synchronization; and decoding mode code (MODCOD) information to obtain frame configuration information after recovering the carrier wave. This method ensures rapid demodulation and reliable demodulated data. | 05-27-2010 |
20120087403 | COMMUNICATION APPARATUS FOR CONTINUOUS PHASE MODULATION SIGNAL - A communication apparatus for a continuous phase modulation signal. The communication apparatus includes a first processing unit configured to generate first information of the continuous phase modulation signal using first symbol data; a symbol converting unit configured to convert the first symbol data into second symbol data or convert the second symbol data into the first symbol data; a symbol storage unit configured to store the second symbol data; a second processing unit configured to second information of the continuous phase modulation signal using the second symbol data stored in the symbol storage unit; a third processing unit configured to generate third information of the continuous phase modulation signal using a modulo operation of an integer related to a modulation index; and an output unit configured to add an output from the third processing unit and an output from the first processing unit and generate the continuous phase modulation signal. | 04-12-2012 |
20120147939 | SIGNAL DEMODULATION METHOD AND APPARATUS AND SIGNAL MODULATION METHOD AND APPARATUS IN RETURN LINK OF SATELLITE SYSTEM - A technology for modulating and demodulating a burst signal in a return link of a satellite system, in which the burst signal is modulated and transmitted from a transmission end of the return link and a symbol of the burst signal is identified and demodulated at a receiving end. The method includes estimating symbol timing of a burst received through the return link and synchronizing the estimated symbol timing of the burst to reference symbol timing; synchronizing a location of the timing-synchronized burst having the symbol timing synchronized to a location of a reference burst using a preamble symbol and a post-amble symbol of the timing-synchronized burst; and recovering a carrier of the location-synchronized burst whose location has been synchronized to the location of the reference burst using a pilot symbol of the location-synchronized burst. | 06-14-2012 |
20120163423 | APPARATUS AND METHOD FOR FRAME SYNCHRONIZATION IN SATELLITE COMMUNICATION SYSTEM - Provided is a frame synchronization apparatus capable of reducing the amount of total computation and computation delays when a receiver of a satellite communication system calculates correlation between an input signal for frame synchronization and a signal sequence of the receiver, since the receiver uses no multiplier. The frame synchronization apparatus includes a correlator to obtain a correlation vale of a unique word of a receiver with respect to a symbol data stream of a frame received from a transmitter of the satellite communication system, a comparator to compare the correlation value to a predetermined threshold value, and a determiner to determine whether the frame has been synchronized, based on the result of the comparison by the comparator. | 06-28-2012 |