Abstract: An apparatus for receiving and processing a broadcast signal in a mobile broadcasting terminal is provided. A preprocessor receives a broadcast signal, converts the broadcast signal into a baseband signal, and then performs OFDM demodulation, Viterbi decoding, and convolutional deinterleaving thereon. A first Reed-Solomon (RS) decoder RS-decodes the signal output from the preprocessor, and outputs a Transport Stream (TS) packet. A checker checks Cyclic Redundancy Check (CRC) of the TS packet. A datagram extractor extracts a datagram having a good CRC result. A datagram controller receives the datagram having a good CRC result and outputs the received datagram to an application controller. The application controller decodes the broadcast data using the datagram received from the datagram controller and provides the decoded broadcast data to a user.

Abstract: An apparatus and method for estimating and combining frequency errors in a mobile communication system. A controller divides data received from a main base station (BS) and control information received from a neighbor BS and controls allocation to fingers. A main automatic frequency control (AFC) loop is formed by estimating and combining frequency errors of the data received from the main BS. A sub AFC loop is formed by subtracting a corrected value of the main AFC loop after estimating and combining frequency errors of the control information received from the neighbor BS.

Abstract: An apparatus and method for carrier frequency synchronization in an Orthogonal Frequency Division Multiplexing (OFDM) system are provided for correcting an initial carrier frequency offset in the OFDM system. A metric generator for frequency estimation performs a first accumulation process for a value computed by multiplying a Phase Reference Symbol (PRS) generated from a reception stage by a Fast Fourier Transform (FFT) output signal for an OFDM symbol in a PRS position within a frame, acquires a differential symbol from a product of adjacent FFT output symbols, performs a second accumulation process for a real part extracted from the differential symbol, and outputs a metric value for the frequency estimation. A maximal value-related index generator compares metric values for initial frequency estimation within a predetermined frequency offset estimation range, and selects and outputs a maximal metric value as a frequency offset estimate.

Abstract: An apparatus and method for recovering a carrier frequency of a received signal using a predefined symbol in an OFDM system is provided. A maximum value detector detects at least three values and their corresponding offsets in descending order among auto-correlation values calculated within a specific frequency offset range between a received signal and a predefined symbol.

Abstract: An apparatus and method for calculating a square root are provided. The square root calculation apparatus calculates an approximated square root for an input value. An integer detector detects a position of a non-zero most significant bit (MSB) from the input value, and outputs an arbitrary integer value. A first approximated linear square root calculator outputs an approximated square root by applying the input value and an even integer value output from the integer detector to a first linear approximation equation. A second approximated linear square root calculator outputs an approximated square root by applying the input value and an odd integer value output from the integer detector to a second linear approximation equation. A controller controls a multiplexer such that the approximated square roots calculated by the first and second approximated linear square root calculators are output according to whether the integer value output from the integer detector is an even number or an odd number.

Abstract: A broadcasting receiving apparatus and method in a broadcasting system are provided. In a broadcasting receiver, a demodulator demodulates a received broadcasting signal, clips a soft metric value for the demodulated signal to a number of bits, and outputs the clipped soft metric value. A mapper maps the clipped soft metric value to an index value with a resolution inversely proportional to the quantization level of the soft metric value. A deinterleaver deinterleaves the index value and a demapper demaps the deinterleaved index value to a representative value being a soft metric value from a range of soft metric values mapped to the index value. A channel decoder decodes the representative value.

Abstract: A method and apparatus for performing channel compensation and symbol demodulation using an estimated channel impulse response during coherent demodulation of a received Orthogonal Frequency Division Multiplexing (OFDM) signal are provided. In the apparatus, an FFT processor IFFT-processes a received signal. A channel compensator generates a channel-compensated signal by multiplying the FFT received signal by an estimated channel impulse response and calculates the power of the estimated channel impulse response. A symbol demodulator sets the power of the estimated channel impulse response as a reference point defining a minimum distance between signal points in a signal constellation, and decides soft metric values for channel decoding using the reference point and I-channel and Q-channel signal components of the channel-compensated signal. A decoder recovers information bits by decoding the soft metric values.

Abstract: A Phase Locked Loop (PLL) is provided for improving acquisition performance in an acquisition state, while preventing performance degradation in a steady state under a low SNR environment, during phase detection, a phase detecting method for the PLL, and a receiver using the same. The PLL determines a period to which an input signal belongs according to the input signal and a feedback signal, outputs an error signal corresponding to the input signal by using a formula (or algorithm) set for the determined period, oscillates a predetermined frequency signal according to the error signal, and feeds back the oscillated signal.

Abstract: A method, apparatus, and system for transmitting and receiving data in a digital broadcasting system based on Orthogonal Frequency Division Multiplexing (OFDM) are provided. A transmitter frames input bit information in a predetermined bit unit, maps the framed input bit information to a transmitter identification indicator (TII) using a predefined number of orthogonal sets, and modulates the TII to an OFDM symbol to transmit the OFDM symbol. A receiver demodulates an OFDM symbol, detects a TII symbol from a predefined orthogonal signal set, demaps predetermined bits from the TII, and concatenates the demapped bits in a predetermined period unit to output bit information. Therefore, the TII can be stably received as a conditional access signal for distinguishing a broadcasting network and a relay network in the digital broadcasting system.

Abstract: An apparatus, method, and system for providing a broadcasting service in a Digital Multimedia Broadcasting (DMB) system with a Single Frequency Network (SFN). Networks of shadow and non-shadow regions can be distinguished in the digital broadcasting system. A conditional access system can be used in the shadow region. A terminal can select a service network. A broadcasting providing server encrypts broadcasting service data, generates private and public keys into which predetermined encryption keys are divided to decrypt the encrypted broadcasting service data, sets at least one broadcasting transmitter for transmitting the private key and/or at least one broadcasting transmitter for transmitting the public key, and provides the encryption keys along with the encrypted broadcasting service data. Broadcasting transmitters transmit the encrypted broadcasting service data received from the broadcasting providing server and the private key using the SFN.

Abstract: An orthogonal frequency division multiplexing (OFDM) system with a multicell or multisector structure includes a plurality of base stations and mobile stations. Each of the base stations interleaves data for transmission to the mobile station, performs space-time coding (STC) on the interleaved data into a plurality of space-time code streams, selects one of the space-time code streams every predetermined code stream selection period such that different space-time code streams are transmitted to at least one cell or sector from among cells or sectors formed by the base station and other base stations, and outputs the selected space-time code stream as an OFDM symbol. Each of the mobile stations STC-decodes a space-time code stream obtained by performing Fourier transform on the OFDM symbol, deinterleaves the STC-decoded data, and channel-decodes the deinterleaved data into its original data.

Abstract: An apparatus and a method are provided for improving reception reliability for control channels by detecting time division multiple (TDM) frames transmitted through the control channels in a TDM mobile communication system. The apparatus and method include receiving the frame through the forward control channel and performing a cyclic redundancy checking (CRC) with respect to the frame, thereby outputting a first error detection bit, measuring reception power for the frame, calculating a first path metric when decoding a channel of the frame, estimating a second path metric by using the first path metric and the reception power, and outputting a second error detection bit by comparing the second path metric with a predetermined threshold value, and creating and outputting a frame quality bit for detecting validity of the frame based on the first and second error detection bits.

Abstract: Disclosed are an apparatus and a method for efficiently transmitting a broadcasting channel by means of cyclic delay diversity in an OFDM mobile communication system. The method comprises the steps of setting each transmitter to have different delay values, the transmitter providing a service to adjacent service areas, generating OFDM signals including the broadcasting data by said each transmitter, delaying the OFDM signals by means of the different delay values, and transmitting the delayed OFDM signals by means of each transmitting apparatus.

Abstract: A method and apparatus for transmitting an orthogonal frequency division multiplexing (OFDM) symbol from a base station to a mobile station in a wireless mobile communication system with a multicell/multisector structure formed by a plurality of base stations. The base station receives a plurality of complex symbols to be transmitted to the mobile station. The base station performs space-time coding (STC) on the plurality of complex symbols and selects the STC-coded symbols such that different space-time code streams are transmitted to adjacent sectors among sectors formed by the base station and other base stations. In addition, a selection pattern of the space-time code streams is updated such that it is circulated every predetermined time period, thereby providing uniform sector diversity for all mobile stations located in a sector/cell boundary.