Abstract:
본 발명은 보안 전송량 산출 방법 및 시스템에 관한 것으로, 보다 구체적으로는 보안 구역이 존재하는 무선 네트워크에서 상대적 거리 변수를 이용하여 보안 전송량을 산출하는 방법 및 시스템에 관한 것이다. 보안 전송량 산출 방법은 송신기와 수신기 간의 거리에 기초하여 도청 노드를 고려한 상대적 거리 변수를 결정하는 단계; 및 상기 상대적 거리 변수를 이용하여 무선 네트워크의 보안 전송량을 산출하는 단계를 포함할 수 있다.
Abstract:
본 발명에 따른 다중 사용자 다중 안테나 통신 시스템에서 백터 퍼터베이션에 기반한 저 복잡도 프리코딩 방법은 후보 심볼의 누적가지 메트릭의 기준값을 결정하는 단계; 결정된 후보 심볼의 누적가지 메트릭의 기준값을 초과하는 누적가지 메트릭 값을 갖는 후보를 제거함과 함께 후보 심볼의 누적가지 메트릭의 기준값을 초과하지 않는 후보 심볼의 누적가지 메트릭 값을 엔트리로 등록하는 단계; 및 엔트리로 등록된 후보 심볼의 누적가지 메트릭 값 중 가장 작은 후보 심볼의 누적가지 메트릭 값을 선택하는 단계를 포함하는 것으로 기존에 사용된 Sphere Encoding 기법과 비교 하여 낮은 복잡도를 가지면서 성능은 유사한 이점이 있다.
Abstract:
PURPOSE: A method for deciding a candidate symbol group in a multi-antenna system is provided to adjust the size of a candidate symbol group according to a channel condition, thereby reducing complexity of a tree search algorithm. CONSTITUTION: Candidate symbol group information is saved(1901). The candidate symbol group information corresponds to a condition number value of a channel. A condition number of the current channel is calculated(1902). The calculated condition number value and the saved condition number value are compared. According to the comparison result, a candidate symbol group of the current channel is determined(1903).
Abstract:
A channel estimation method based on impulse symbols and record media including a program for embodying the same are provided to obtain exact channel information by estimating channels based on impulse response, which is obtained from a time domain. A null postfix(104) is added to an output value of an IFFT(Inverse Fast Fourier Transform) unit that executes no IFFT. An in pulse symbol is added to the output value added the null postfix. By re-adding the null postfix to the impulse symbol, an orthogonal frequency division multiplexing symbol is formed. A channel impulse response is extracted from a time domain based on the formed orthogonal frequency division multiplexing symbol. Delay components more than a reference level are extracted from the extracted channel impulse response. A channel is estimated by forming a channel matrix using an interpolation with respect to a sampling frequency on the extracted delay components.
Abstract:
PURPOSE: Secure transmission amount calculation method and system using a relative distance variable in a wireless network in which a secure section exists are provided to calculate more realistic secure transmission amount by considering a relative distance between receiver and tapping node based on a transmitter. CONSTITUTION: A secure transmission amount calculation system determines a relative distance variable based on a radius of secure region and a distance between transmitter and receiver (401). The secure transmission amount calculation system determines optimal electric power distribution variable in a closed form (402). The secure transmission amount calculation system calculates a secure transmission amount by finding the optimal electric power distribution variable (403). [Reference numerals] (401) Determine a relative distance variable; (402) Determine an optimal electric power distribution variable; (403) Determine optimal secure transmission amount; (AA) Radius of a secure region(d_zone); (BB) Distance between a transmitter and a receiver(d_R); (CC) Secure transmission amount is closed; (DD) Disperse channel electric power; (EE) Secure transmission amount
Abstract:
PURPOSE: A transceiving method in a multiple antenna system for reducing necessary computational complexity in selection or the quantization of a coding word is provided to remove interference between multi users by quantizing error. CONSTITUTION: A transmitter receives a codebook index from a plurality of terminals(300). The transmitter selects the k terminal of a plurality of terminals(302). The transmitter generates the precoder matrices P put through to the codebook index of the selected terminal(304). The transmitter performs precoding(306). The transmitter transmits the transmission signal of which the precoding is performed for the first time slot(308).
Abstract:
A method for transmitting and receiving data including an impulse symbol for estimating a channel in a MIMO(Multiple Input Multiple Output) OFDM(Orthogonal Frequency Division Multiplexing) and an IP(Impulse Postfix) OFDM system of an MIMO method are provided to improve channel estimation performance by using an orthogonal impulse in each channel. An IP OFDM system of an MIMO method includes a transmitter. A serial to parallel transform unit(101) converts the serially inputted data symbol to the parallel data symbol. An STBC/SFBC encoder(102) encodes the parallel data symbol inputted from the serial to parallel converter through one of STBC(Space-Time Block Coded) or SFBC(Space-Frequency Block Coded) method and comprises the signal. An IFFT(Inverse Fast Fourier Transform) unit(103) performs IFFT of data encoded in the STBC/SFBC encoder and converts the data into the signal in a time axis. A parallel to serial transform unit(104) converts data transformed in the IFFT unit into the serial data. An IP insertion unit inserts the impulse symbol for estimating the channel into a guard interval in a time axis of the data converted to the time domain.
Abstract:
본 발명은 직교주파수 분할 다중화(Orthogonal Frequency Division Multiplexing, OFDM) 방식의 통신 시스템에서 채널 추정을 위한 최적 크기의 임펄스 심볼(impulse symbol)을 포함하는 데이터 송신 방법에 관한 것으로서, 더욱 상세하게는 OFDM 시스템에서 채널 추정을 위하여, 시간축상의 데이터 심볼(data symbol)들 사이의 보호구간(guard interval)에 임펄스 심볼(impulse symbol)을 삽입하는 방법(Impulse Postfix, IP)을 적용함에 있어, 최적의 채널 추정 및 비트 오율(Bit Error Rate, BER) 성능을 유지하는 임펄스 심볼(impulse symbol) 크기를 결정하여 데이터 심볼(symbol)들 사이에 삽입하여 데이터를 송신하는 방법에 관한 것이다. 본 발명에 의하면, OFDM 시스템의 데이터 송수신에 있어서 적정 수준의 PAPR(Peak to Average Power Ratio)를 만족하면서 기존 채널 추정 기법들에 비해 향상된 비트 오율(Bit Error Rate, BER) 성능을 유지할 수 있다. 임펄스 포스트픽스(Impulse Postfix, IP), 임펄스 크기, OFDM
Abstract:
PURPOSE: A channel feedback device in a mobile communications system and a method thereof are provided to improve feedback efficiency through feedback of elements of Grassmannian space which represents a row space. CONSTITUTION: Using a signal received from a transmission end, a channel is estimated(203). Using an orthogonalization technique, a normal form about the estimated channel is produced(205). A row operation of a matrix, which is produced according to the normal form, is performed. A first matrix which includes row space information of the estimated channel is produced(207). After the first matrix is quantized, the quantized matrix is fed back to the transmission end(209).