Abstract: The present invention relates to a method and apparatus for transmitting digital broadcasting signals and a method and apparatus for receiving digital broadcasting signals that divide a stream into a plurality of layers according to characteristics of the stream, that independently process the layers, and that dynamically allocate frequencies on the basis of the processed signals. A method of transmitting digital broadcasting signals includes dividing a single stream into a plurality of layers according to characteristics of the stream; performing encoding and mapping on each of the layers; and dynamically allocating a frequency to each of the layers on the basis of the number of symbols for each layer.

Abstract: Provided is a channel estimation apparatus and method using a linear/nonlinear average in a wireless communication system. The present research provides a channel estimation apparatus and method for estimating a channel between a transmitter and a receiver from a pilot-inserted OFDM signal and linearly or nonlinearly averaging the estimating channel, thereby preventing the equalizer performance from being degraded by noise component of the estimated channel and noise amplification caused by deep fading. The channel estimation apparatus includes: a channel estimation unit configured to estimate a channel coefficient of a channel between a transmitter and a receiver from a pilot-inserted carrier signal according to pilot arrangement; and a linear/nonlinear averaging unit configured to linearly or nonlinearly averaging the estimated channel coefficient, thereby preventing an equalizer performance from being degraded by noise component existing in the channel and noise amplification caused by deep fading.

Abstract: In a method of registering with an access point in a terminal of a wireless communication system, a frame includes a downlink sub-frame including a broadcast interval and a first management connection interval, and an uplink sub-frame including an access interval and a second management connection interval, the broadcast interval being used for transmitting a map message, the method includes: sending a first ranging request message to the access point using the access interval; receiving allocation information of a ranging slot from the access point using the map message; performing ranging through the ranging slot; sending a registration request message to the access point using the second management connection interval; and receiving information on whether to permit the registering from the access point using the first management connection interval.

Abstract: The MAC frame in a wireless communication system includes a terminal ID allocated to each of multiple terminals. At least one connection ID is allocated to each terminal having the terminal ID, and sub-carrier allocation information is allocated to each connection having the connection ID. The sub-carrier allocation information includes a sub-carrier allocation status for each sub-carrier, and the number of allocated information bits for each sub-carrier. The sub-carrier allocation status and the number of allocated information bits for each sub-carrier can be allocated, by sub-carriers, to the sub-carrier allocation information using a same number of bits; or the information on the sub-carrier allocation status is first allocated to the sub-carrier allocation information and the number of allocated information bits for each sub-carrier is allocated.

Abstract: In a method for transmitting data from a first node to a second node through first and second relay units in a wireless communication system: a) a first symbol is transmitted from the first node to the second node and the first relay unit during a first time slot section; b) the first symbol, which is received from the first node, is transmitted from the first relay unit to the second node during a second time slot section; c) a second symbol is transmitted from the first node to the second node and the second relay unit during the second time slot section; and d) the second symbol, which is received from the first node, is transmitted from the second relay unit to the second node during a third time slot section.

Abstract: The MAC frame in a wireless communication system includes a terminal ID allocated to each of multiple terminals. At least one connection ID is allocated to each terminal having the terminal ID, and sub-carrier allocation information is allocated to each connection having the connection ID. The sub-carrier allocation information includes a sub-carrier allocation status for each sub-carrier, and the number of allocated information bits for each sub-carrier. The sub-carrier allocation status and the number of allocated information bits for each sub-carrier can be allocated, by sub-carriers, to the sub-carrier allocation information using a same number of bits; or the information on the sub-carrier allocation status is first allocated to the sub-carrier allocation information and the number of allocated information bits for each sub-carrier is allocated.

Abstract: The present invention relates to a multi-input multi-output (MIMO) system for enhancing transmission performance. The MIMO system uses space-time encoding and transmit antenna selection methods, and includes a transmitter (100) and a receiver (200). The transmitter (100) includes N transmit antennas (130-1, 130-4) that are more than M tansrni antennas (130-1, 130-3) used for transmitting a signal to space channel, selects the M transmit antennas (130-1, 130-3) among the N transmit antennas (130-3 130-4), and transmits symbol by space-time encoding the symbol. The receiver (200) includes M receive antenna (120-1, 210-2) for receiving a signal from the space channel, detects an information symbol by using the signal received through the receive antenna (210-1, 210-2), generates transmit antenna selection information for selecting M transmit antennas (130-1, 130-3) among transmit antennas (i30-1, . . . 7130-4) with reference to a channel estimate, and returns the information to the transmitter.

Abstract: A space-time code used for a transmitter to transmit a plurality of data symbols to a receiver in a MIMO system, the space-time code including a code word matrix for transmitting an amount of data symbols corresponding to a product of the number of transmit antennas and a spatial multiplexing rate during one block period, wherein a row index indicates combined signals transmitted through different transmit antennas and a column index indicates time slots that correspond to the number of transmit antennas, and wherein the number of data symbols allocated to each transmit antenna in a code block corresponds to the spatial multiplexing rate, and the data symbols are combined by different combining coefficients for each transmit antenna at every time slot, and simultaneously transmitted through different transmit antennas, and each transmit antenna transmits a different set of data symbols at every time slot.

Abstract: The MAC frame in a wireless communication system includes a terminal ID allocated to each of multiple terminals. At least one connection ID is allocated to each terminal having the terminal ID, and sub-carrier allocation information is allocated to each connection having the connection ID. The sub-carrier allocation information includes a sub-carrier allocation status for each sub-carrier, and the number of allocated information bits for each sub-carrier. The sub-carrier allocation status and the number of allocated information bits for each sub-carrier can be allocated, by sub-carriers, to the sub-carrier allocation information using a same number of bits; or the information on the sub-carrier allocation status is first allocated to the sub-carrier allocation information and the number of allocated information bits for each sub-carrier is allocated.

Abstract: Disclosed are a method for constructing a frame preamble in an OFDM wireless communication system, and a method for acquiring frame synchronization and searching cells using the preamble. The preamble is arranged at the beginning of a frame and constructed of a pattern repeated an integer number of times, and a CP. The pattern has a length shorter than a single OFDM symbol interval. The length of the repetitive pattern is not limited to an integer number of times a single OFDM symbol interval. Frame synchronization can be acquired by observing cross-correlation of a received signal and reference patterns and detecting the moment when the absolute value of the cross-correlation exceeds a predetermined threshold. Otherwise, frame synchronization can be acquired by observing auto-correlation of the received signal using repeated patterns included in the received signal and detecting the moment when the absolute value of the auto-correlation becomes the maximum value.

Abstract: Disclosed is a signal transmission method in a mobile communication system. Unequal error protection (UEP) ratios are determined so that the bits may have different received qualities according to the weights of the bits. The bits are repeated by a bit sequence repeater (210) according to the determined UEP ratios to generate a repeated bit sequence having a predetermined number of bits. The generated repeated bit, sequence is interleaved by an interleaver (220) and the interleaved bit sequence is symbol-mapped by a symbol-mapper (230) to generate a transmission symbol sequence, and the generated transmission symbol sequence is transmitted by the transmitter to a receiver. Furthermore, also a corresponding signal reception method, a corresponding signal transmitter and a corresponding signal receiver are disclosed.

Abstract: A method for tracking carrier frequency and sampling frequency offsets in an OFDM wireless communication system comprises: (a) detecting data received from the transmitter using a first signal, and tracking a phase offset caused by the carrier frequency offset using the detected received data; (b) detecting the data received from the transmitter using the first signal, and tracking the phase offset caused by the sampling frequency offset using the detected received data; (c) compensating for the phase offset caused by the carrier frequency offset between the transmitter and the receiver according to the phase offset tracked in (a); and (d) compensating for the phase offset caused by the sampling frequency offset between the transmitter and the receiver according to the phase offset tracked in (b).

Abstract: An apparatus for estimating a RSSI of a signal transmitted/received in a wireless network, the apparatus including an ADC quantizing one of I-branch and Q-branch signals, extracted from the signal, into a digital signal; an absolute value calculating unit calculating an absolute value of the digital signal quantized by the ADC and outputting a result; an accumulate unit accumulating an output of the absolute calculating unit for a given time period and outputting a result; a square unit squaring an output of the accumulate unit and outputting a result; and a multiply unit multiplying an output of the square unit by a given value and outputting a result, the given value being determined based on the number of input bits, an input clip level, and input resistance of the ADC when the probability density functions at input and output signals of the ADC are approximately Gaussian with zero mean.

Abstract: Disclosed is a method for allocating data and pilots, a transmitting method and device, a receiving method and device in an OFDMA system. A terminal partitions subcarrier groups and symbols from an uplink channel based on a basic pilot pattern generated by a specific reference, receives at least one subchannel based on the partitioned subcarrier groups and symbols, hops the subcarrier groups caused by the subchannel according to hopping patterns, allocates data, and differently positions the pilots per subcarrier group based on the basic pilot pattern. Accordingly, the probability of pilot collision between adjacent cells is reduced, and accuracy of channel estimation is increased through boosting the pilot subcarrier power.

Abstract: The present invention relates to a method for timing acquisition and carrier frequency offset estimation of an OFDM communication system and an apparatus using the same. For this purpose the present invention provides a method for calculating at least one auto-correlation and calculating an observation value by performing a sliding sum on the at least one auto-correlation, and calculating a peak point of an absolute value of the observation as frame timing. In addition, the present invention provides a method for generating a third OFDM symbol that is generated by delaying a second OFDM symbol, calculating an observation value through the second and third OFDM symbols, and calculating a phase difference from a result of multiplication of the observation value and a conjugate complex value of the observation value such that a carrier frequency offset can be estimated.

Abstract: A rain attenuation compensation method that includes estimating a signal-to-noise (S/N) ratio from PSK-modulated receiving signal at a receiving end; predicting a signal-to-noise (S/N) ratio of the next time point on the basis of the signal-to-noise (S/N) ratio values of the past and present time points; and determining which of transmission methods is adequate to the predicted signal-to-noise (S/N) ratio of the next time point. If the switching of the transmission method is determined, a control signal for inquiring the change of the transmission method is transmitted to a transmitting and a receiving end. Data is then transmitted by the switched transmission method.

Abstract: The MAC frame in a wireless communication system includes a terminal ID allocated to each of multiple terminals. At least one connection ID is allocated to each terminal having the terminal ID, and sub-carrier allocation information is allocated to each connection having the connection ID. The sub-carrier allocation information includes a sub-carrier allocation status for each sub-carrier, and the number of allocated information bits for each sub-carrier. The sub-carrier allocation status and the number of allocated information bits for each sub-carrier can be allocated, by sub-carriers, to the sub-carrier allocation information using a same number of bits; or the information on the sub-carrier allocation status is first allocated to the sub-carrier allocation information and the number of allocated information bits for each sub-carrier is allocated.

Abstract: A method for tracking carrier frequency and sampling frequency offsets in an OFDM wireless communication system comprises: (a) detecting data received from the transmitter using a first signal, and tracking a phase offset caused by the carrier frequency offset using the detected received data; (b) detecting the data received from the transmitter using the first signal, and tracking the phase offset caused by the sampling frequency offset using the detected received data; (c) compensating for the phase offset caused by the carrier frequency offset between the transmitter and the receiver according to the phase offset tracked in (a); and (d) compensating for the phase offset caused by the sampling frequency offset between the transmitter and the receiver according to the phase offset tracked in (b).

Abstract: A rain attenuation compensation method using adaptive transmission technique and system using the same compensate a signal attenuation caused by rain in a satellite communication system through an adaptive transmission technique. As an adaptive transmission technique, the method and apparatus employ an adaptive coding using a block turbo code and an adaptive modulation using M-ary PSK modulation. The inventive method estimates a signal-to-noise (S/N) ratio at a receiving end, predicts a signal-to-noise (S/N) ratio at the next time point, allocates the most appropriate transmission method to the predicted signal-to-noise (S/N) ratio, thereby adaptively compensating a rain attenuation.