Abstract: An apparatus is provided for transmitting a signal in a communication system using a Low Density Parity Check (LDPC) code. A controller determines a number of ‘0’s to be inserted in information data according to a first coding rate to be applied when generating the information data into an LDPC code, and determines the number of ‘0’s to be removed from the LDPC code. A ‘0’ inserter inserts ‘0s’ in the information data according to control of the controller. An LDPC encoder generates the LDPC code by encoding the ‘0’-inserted signal according to a first parity check matrix. A ‘0’ remover removes the inserted ‘0’s from the LDPC code.

Abstract: Disclosed is a method for transmitting a signal in a signal transmission system, which includes demultiplexing a bit stream to be transmitted into a first bit stream and a second bit stream; generating a first coded bit stream by coding the first bit stream according to a first coding rate and generating a second coded bit stream by coding the second bit stream according to a second coding rate; and generating a coded symbol by concatenating the first coded bit stream and the second coded bit stream.

Abstract: A sensor network communication system interworking with a BWA communication system and a communication method therefor are provided. In a method for measuring a predetermined target in the sensor network communication system interworking with the BWA communication system, a mobile station or a server sends a measurement request for the predetermined target to a local controller over the BWA communication system. The local controller sends the measurement request to a predetermined sensor and actuator over a wireless communication protocol. The sensor and actuator measures the predetermined target and sends the measurement value to the local controller. The local controller sends a measurement result message based on the measurement value to the mobile station or the server.

Abstract: Disclosed is a method and apparatus for completely recovering received data with high reliability using LDPC codes without short-sized cycles in a digital communication system using an error-correcting code. The method includes performing exponent conversion of a predetermined number of exponent matrixes stored in advance in a memory so as to generate new exponent matrixes based on the exponent conversion, and generating new LDPC codes using the new exponent matrixes.

Abstract: An apparatus and method for transmitting and receiving a signal according to a change of downlink channel information by a mobile station in a broadband wireless access communication system. The method includes: detecting the change of the downlink channel information; receiving a report from a base station that there is data for the mobile station; and reporting the change of the downlink channel information to the base station, so that the base station and the mobile station have same downlink channel information.

Abstract: An apparatus and method for canceling ISI in a broadband wireless communication system are provided. In a transmitter of the broadband wireless communication system, a controller acquires a CP length, a puncturing pattern, and a time sample interval according to a delay spread. A puncturer punctures coded data in the puncturing pattern. An IFFT processor IFFT-processes the punctured coded data and outputs sample data. A CP inserter generates an OFDM symbol by inserting a copy of a last part of the sample data before the sample data. Here, the length of the last part of the sample data is equal to the CP length. A D/A converter converts the OFDM symbol to an analog signal at a sampling rate determined by the time sample interval.

Abstract: Disclosed is a method for transmitting a pilot symbol from base stations (BSs) to a subscriber station (SS) in a communication system which includes the base stations located adjacent to each other, the method includes the steps of transmitting BS-identifying sub-carriers which represent sequences for identifying the base stations in a frequency domain of the pilot symbol; and transmitting PAPR (Peak to Average Power Ratio) sub-carriers which represent sequences for reducing a PAPR of the pilot symbol together with the transmission of the BS-identifying sub-carriers in the frequency domain.

Abstract: Disclosed is an apparatus and method for allocating downlink/uplink subchannels for a soft handover in a broadband wireless access communication system, wherein the method includes the steps of configuring FUSC subchannels based on a predetermined FUSC subchannel configuration scheme by using an equal seed value in all cells; allocating a predetermined number of FUSC subchannels of the configured FUSC subchannels as soft handover subchannels; and allocating remaining subchannels, except for the FUSC subchannels allocated as the first subchannels, as non-soft handover subchannels based on the FUSC subchannel configuration scheme by using a specific seed value.

Abstract: A method for setting a guard interval for distinguishing a transition from a downlink period to an uplink period in a mobile communication system employing a time division duplexing (TDD) scheme, the mobile communication system including a plurality of base stations. The method includes the steps of, simultaneously transmitting by each of the base stations downlink signals from transmission antennas at a first time point based on a processing delay time for a signal to be transmitted; simultaneously receiving by each of the base stations an uplink signal at reception antennas at a second time point; and setting a time interval from the first time point to the second time point as a guard interval for distinguishing a transition from an uplink period to a downlink period.

Abstract: Disclosed is a method for supporting a handover in a broadband wireless access communication system which includes a mobile subscriber station, a serving base station currently providing service to the mobile subscriber station, and a plurality of adjacent base stations different from the serving base station, in which each of the base stations includes cells using subchannel bands different from each other, the method including establishing a set of base stations which currently provide wireless channels for data transmission/reception to the mobile subscriber station; classifying, by each base station, entire subchannels into a plurality of sets of subchannels; and allocating each of the sets of subchannels obtained by the classification to a PUSC (Partial Usage of Subchannels) subchannel area of each sector, wherein, every base stations included in an active set select an equal number of PUSC subchannels from among a PUSC subchannel area allocated to each of the base stations and allocate the selected PUSC

Abstract: A method for supporting a handover in a broadband wireless access communication system including an MSS, a serving BS providing service to the MSS, and a plurality of neighbor base stations, in which each of the BSs includes cells using different sub-channel bands. The method includes: measuring, by the BSS, intensities of signals received from the BSs, transmitting to the serving BS a request for a handover based on the measured signal intensities, establishing a connection with a target BS, to which a handover of the MSS is requested, from among the neighbor BSs before terminating a connection with the serving BS, and performing a soft handover by establishing a simultaneous connection with the two BSs in a handover area. The serving BS and the target BS allocate the same sub-channel including the same sub-carriers to the MSS when the mobile subscriber station performs the soft handover.