Abstract: Provided are a preamble structure and a channel estimation algorithm thereof. A communication method for a transmitter for channel estimation in a Multiple Input Multiple Output (MIMO) wireless communication system having N receiving antennas, includes generating a preamble interval having a short training field that includes a predetermined pattern iterated N times on a time domain and is used for compensating for a carrier frequency offset, and transmitting a packet having the preamble interval.

Abstract: A transmission method performed by a mobile station for random access channel (RACH) burst transmission diversity gain is provided. According to the method, a variety of combinations of a time switching transmit diversity (TSTD) technique, a frequency hopping technique, and a power ramping technique that are robust against fading channel environments are applied to transmission of an RACH burst, thereby increasing the probability of detecting an RACH signature of a base station. Also, by using the transmission parameters (subband frequencies, transmission antennas, power, etc.) which are used for successful transmission of an RACH burst, for transmission of a successive user packet data, reliable transmission of the successive user packet data can be performed.

Abstract: A transmission method performed by a mobile station for random access channel (RACH) burst transmission diversity gain is provided. According to the method, by combining and using switching diversity by beam forming, frequency hopping, and power ramping, the probability that when the speed of a mobile station is low, the mobile station falls into a deep fading environment is lowered, thereby increasing the probability of detecting an RACH signature of the base station. Also, by using the transmission parameters (subbands, precoding matrixes, power, etc.) which are used for successful transmission of an RACH burst, for transmission of a successive user packet data, reliable transmission of the successive user packet data can be performed.

Abstract: Provided is an apparatus and method for detecting timing errors based on characteristics of cyclic correlation. The apparatus and method can detect the timing errors of many users by using the cyclic characteristics of a midamble code at a time and detects the timing errors based on the characteristics of cyclic correlation to reduce the time required for detecting the users and lower the complexity in terms of Hardware. The apparatus includes a detection section controller, a register, a midamble generator, a midamble shifter, an accumulator, an adder, a shift register and a timing error detector.

Abstract: The invention provides a method of generating a downlink signal and searching a cell on the basis of the downlink signal in an OFDM-based cellular system. The downlink signal includes a plurality of synchronization blocks each having a plurality of sub-frames, and a synchronization pattern composed of a combination of a cell group identification code for identifying a cell group and a frame synchronization identification code for indicating a frame start point is generated in each of the synchronization blocks. Different frame synchronization identification codes are allocated to the synchronization blocks.

Abstract: A method for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses at least one channel, includes the steps of: a) encoding the source data to generate at least one data part and a control part; b) generating at least one spreading code to be allocated to the channel, wherein each spreading code is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on same point or symmetrical with respect to a zero point on a phase domain; and c) spreading the control part and the data part by using the spreading code, to thereby generate the channel-modulated signal. The method is capable of improving a power efficiency of a mobile station by reducing a peak-to-average power ratio in a mobile communication system.

Abstract: Provided are a cell search method, a forward link frame transmission method, an apparatus using the methods, and a forward link frame structure in an Orthogonal Frequency Division Multiplexing cellular system, wherein the time it takes to perform a cell search and the complexity of the cell search can be reduced. The cell search apparatus includes a sync acquirer which receives a signal according to a forward link frame comprising a plurality of sync channel symbols each having different intervals between the adjacent sync channel symbols and achieves synchronization of the sync channel symbols using a sync channel of the received signal, and a boundary detector which detects a frame boundary using an interval pattern between the sync channel symbols, based on the achieved synchronization.

Abstract: Provided are a cell search method, a frame transmission method thereof, and a forward link frame structure thereof.

Abstract: The present invention relates to a terminal board applied to a multi-band and multi-carrier wireless system and an apparatus thereof. The terminal platform apparatus according to an exemplary embodiment of the present invention includes a multi-band multi-carrier terminal platform board, a monitoring device, an RF unit for a multi-band multi-carrier system, and a GPS/power source supply. The multi-band multi-carrier terminal platform board achieves high speed data processing and high quality data transmission by using a plurality of high performance FPGAs, an ARM processor, a DPRAM, and a CardBus interface. The monitoring device performs real-time debugging operations, and the GPS/power source supply supplies a power source to the multi-band multi-carrier terminal platform board.

Abstract: The present invention provides a coding device of a low-density parity-check (LDPC) code for simply coding information data without generating a code generator matrix. The coding device forms a parity-check matrix having two sub-matrixes. At this time, the first sub-matrix is a random matrix or a structural matrix. The second sub-matrix is a structural matrix having two 1s in each column. Parity data is calculated by using the structural second matrix without calculating an inverse matrix of the second matrix when temporary data is generated by using the first sub-matrix with reference to the information data. Code data is generated from the parity data and the information data and is transmitted.

Abstract: The present invention provides an OFDM symbol generating apparatus. The OFDM symbol generating apparatus generates a plurality of weight-applied symbol groups by applying a plurality of weights to a digital modulation symbol group, and generates a plurality of IFFT symbol groups by performing an IFFT operation on the plurality of weight-applied symbol groups. Subsequently, an IFFT symbol group having the minimum PAPR is selected from among the plurality of IFFT symbol groups such that a characteristic of a PAPR can be improved without reducing data transmission speed.

Abstract: The present invention relates to a packet data transmission method in an OFDMA system and an apparatus thereof. The present invention provides a user packet data transmission method including generating a RACH burst for channel information estimation, selecting a first antenna among a plurality of antennas, transmitting the RACH burst through the first antenna to a base station, receiving a data transmission acceptance signal from the base station, in response to the RACH burst, transmitting user packet data through the first antenna when receiving a signal indicating that the data transmission is allowed, and selecting a second antenna that is difference from the first antenna and transmitting a RACH burst through the second antenna when receiving a signal indicating that the data transmission is not allowed, and a transmitting apparatus of a mobile station having the plurality of antennas.

Abstract: Provided is a method and apparatus for discontinuously transmitting/receiving packets for low-power consumption of a terminal in a cellular system for packet transmission. The present research provides a method and apparatus that can perform a low-power consuming operation when a terminal is in active state in a cellular system. The method for discontinuously transmitting/receiving packet data to reduce power consumption of a terminal in a cellular system, including the steps of: a) establishing discontinuous reception/transmission (DRX/DTX) parameters including discontinuous DRX/DTX cycle information for terminals operating in a transmission suspension mode, which is a sub-state of an active state; and b) performing DRX/DTX based on the DRX/DTX parameters in the terminals operating in the transmission suspension mode.

Abstract: A method for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses at least one channel, includes the steps of: a) encoding the source data to generate at least one data part and a control part; b) generating at least one spreading code to be allocated to the channel, wherein each spreading code is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on same point or symmetrical with respect to a zero point on a phase domain; and c) spreading the control part and the data part by using the spreading code, to thereby generate the channel-modulated signal. The method is capable of improving a power efficiency of a mobile station by reducing a peak-to-average power ratio in a mobile communication system.

Abstract: The present invention relates to an orthogonal frequency division multiplexing (OFDM) signal transmitting and receiving device, in which a peak to average power ratio characteristic is improved without reducing a data D transmission speed. The OFDM signal transmitting device separates a digital modulated symbol as a real part and an imaginary part, and performs discrete cosine transform (DCT) and discrete sine transform (DST) operations respectively for real and imaginary part symbols, performs an inverse fast Fourier transform operation, and generates an OFDM symbol. The OFDM signal receiving device performs a fast Fourier transform operation for the OFDM symbol, and performs an inverse DCT operation and an inverse DST operation, performs a digital demodulating operation, and generates a final binary data symbol.

Abstract: Provided is an error correcting method that can provide improved error correction efficiency in a multimedia broadcast/multicast service (MBMS) by marking the presence of an error in a Protocol Data Unit (PDU) with an error instead of discarding the erroneous PDU in an MBMS terminal of the MBMS system, which performs error correction in an application layer, and transmitting the erroneous PDU together with a PDU without an error to the application layer, and an error correction apparatus employing the method. The MBMS terminal includes: a radio link control (RLC) protocol processor configured to receive PDUs generated from the reception data, generate service data units (SDUs) by combining the PDUs, mark whether there is an SDU recovered from a PDU with an error, and output the SDUs; and a packet data convergence protocol (PDCP) processing means configured to receive and deliver the SDUs.

Abstract: The present invention relates to a transmit diversity method of a mobile communication system and a base station transmitting apparatus using the same. A first code and a second code that is diversity-encoded from the first code are generated, and transmit symbols are spread with the first code and the second code. A first transmit symbol spread with the first code and a second transmit symbol spread with the second code are mapped to symbols in frequency and time domains in a frame and transmitted through antennas. Therefore, various diversity techniques can be provided to the mobile communication system, and the diversity technique is not restricted to symbols transmitted to the same mobile station and can also be applied to a 1-bit channel.

Abstract: In a cellar system providing various packet services, sleep mode operation of a terminal in an idle state is controlled. The cellular system determines a discontinuous receiving (DRX) period according to a QoS of a packet service provided to the terminal, and runs the sleep mode according to the determined DRX period. The cellular system runs the sleep mode divided into shallow sleep duration and deep sleep duration. With this manner, a paging delay to the terminal and a power consumption of the terminal may be reduced.

Abstract: The present invention relates to a mobile terminal for efficiently measuring a carrier to noise and interference ratio (CNIR) in an orthogonal frequency division multiplexing (OFDM) mobile communication system and a CNIR method thereof. The mobile terminal includes a frequency offset and frame detector for detecting frame timing information and frequency offset from a received signal, a demodulator for demodulating the received signal by using the detected frame timing information and frequency offset, a subchannel separator for separating a data symbol from symbols outputted by the demodulator, a channel estimating and equalizing unit for estimating and equalizing a channel for the corresponding subchannel from the data symbol, and a CNIR measuring unit for transmitting a measured current CNIR to the base station.

Abstract: An orthogonal complex spreading method for a multichannel and an apparatus thereof are disclosed. The method includes the steps of complex-summing ?n1WM,n1Xn1 which is obtained by multiplying an orthogonal Hadamard sequence WM,n1 by a first data Xn1 of a n-th block and ?n2WM,n2Xn2 which is obtained by multiplying an orthogonal Hadamard sequence W1,n2 by a second data Xn2 of a n-th block; complex-multiplying ?n1WM,n1Xn1+j?n2WM,n2Xn2 which is summed in the complex type and WM,n3+jPWM,n4 of the complex type using a complex multiplier and outputting as an in-phase information and quadrature phase information; and summing only in-phase information outputted from a plurality of blocks and only quadrature phase information outputted therefrom and spreading the same using a spreading code.