Abstract: Disclosed is a data transmitter, including: a demultiplexer configured to demultiplex a data subcarrier, and a training sequence or a pilot subcarrier included in a signal which needs to be frequency-shifted among a plurality of signals; a frequency shift unit configured to frequency-shift the demultiplexed data subcarrier based on a predetermined frequency; a superposition unit configured to generate a polarization signal by superimposing the demultiplexed training sequence or pilot subcarrier, and the frequency-shifted data subcarrier; and a polarization antenna configured to transmit a signal which need not be frequency-shifted and the generated polarization signal among the plurality of signals.

Abstract: Disclosed is a communication system including a first communication apparatus and a second communication apparatus that communicate with each other through a dual polarization antenna, the system including: a first communication apparatus which calculates a co-polar ratio defined by a ratio of a first channel gain for a first polarization and a second channel gain for a second polarization; and a second communication apparatus which calculates a first rotation angle for the first polarization and a second rotation angle for the second polarization, respectively, by using the co-polar ratio transferred from the first communication apparatus, and transmits to the first communication apparatus a first rotational polarization generated by rotating the first polarization at the first rotation angle and a second rotational polarization generated by rotating the second polarization at the second rotation angle.

Abstract: There are provided a method of generating a ranging signal of a wireless terminal and a device for generating a ranging signal of a wireless communication system that can generate the ranging signal using one IFFT engine independently from a mode of the ranging signal transmitted in uplink in a wireless communication system in which a frequency interval of subcarriers used to generate an initial ranging signal and a frequency interval of subcarriers using periodic ranging are different. In this way, it is possible to decrease complexity of hardware and design of the wireless terminal, and decrease power consumption of the wireless terminal through hardware simplification.

Abstract: Disclosed is an apparatus for transmitting multiple streams, including: a polarized wave control unit generating non-orthogonal polarization information for three or more input streams; a polarized wave generating unit polarizing three or more input streams in a baseband based on the non-orthogonal polarization information to generate vertical and horizontal polarization components; and a polarized wave transmitting unit transmitting the plurality of vertical and horizontal polarization components through dual polarization antennas.

Abstract: There are provided a method of generating a ranging signal of a wireless terminal and a device for generating a ranging signal of a wireless communication system that can generate the ranging signal using one IFFT engine independently from a mode of the ranging signal transmitted in uplink in a wireless communication system in which a frequency interval of subcarriers used to generate an initial ranging signal and a frequency interval of subcarriers using periodic ranging are different. In this way, it is possible to decrease complexity of hardware and design of the wireless terminal, and decrease power consumption of the wireless terminal through hardware simplification.

Abstract: Disclosed is a method and apparatus for composing a received symbol signal modulated with a bit reflected Gray code into bit information. According to an embodiment of the present invention, a positive integer of the received symbol signal having bits is assigned according to the Gray mapping rule, and a sign is determined. A value that is indicative of an arrangement of the bits constituting the received symbol signal is calculated. A boundary value in at least one bit group consisting of the bits constituting the received symbol signal is acquired, and a difference from an absolute value of the received symbol signal is calculated. The received symbol signal is converted into information per bit using a value of the received symbol signal based on the positive integer and the determined sign, the value that is indicative of the bit arrangement, and the difference from the absolute value.

Abstract: Disclosed are a row-vector norm comparison method and a row-vector norm comparison apparatus for an inverse matrix. A row-vector norm comparison apparatus includes: an input matrix processing module that receives and combines constituent elements of a matrix; a cofactor operation module that multiplexes the combination result of the constituent elements to calculate factors constituting an adjoint matrix; a square calculation module that squares the calculated factors; a summation module that selects a predetermined number of factors among the squared factors and sums the selected factors to calculate the norms of row vectors in an inverse matrix; and a norm comparison module that outputs a comparison result of the calculated norms of the row vectors.

Abstract: The present invention relates to a transmission symbol detection method in a multiple antenna system. In the present invention, when a channel matrix is estimated through channel estimation, a receiving side calculates a Q matrix and an R matrix through QR decomposition that is more simplified than a typical QR decomposition from an augmented channel matrix that includes the estimated channel matrix. In addition, the receiving side detects symbols having the minimum Euclidean metric by using the two matrixes, as transmission symbols.

Abstract: The present invention relates to a signal detection method and a receiving apparatus in a multiple input multiple output (MIMO) system. More particularly, the present invention relates to a signal detection device in a MIMO system using a spatial multiplexing (SM) method. In the signal detection method, a channel is estimated and layers are rearranged according to a predetermined layer arrangement rule. QR-decomposition is performed by using a rearranged system model, all constellation points in a symbol of a layer having the lowest reliability are considered, and symbols are detected by using a sequential interference elimination method.

Abstract: The present invention relates to a method of calculating a soft value and a method of detecting a transmission signal. The present invention estimates a channel on the basis of a received signal and rearranges a plurality of data streams. Further, a plurality of substitute vectors are selected from the rearranged data streams and a metric corresponding to each of the substitute vector is calculated. Further, a threshold value is calculated from a metric calculated for each of the substitute vectors and a soft value of each bit of a transmission signal is calculated from the metric and threshold value corresponding to each of the substitute vectors.

Abstract: The present invention relates to a method of detecting a candidate vector and a method of detecting a transmission symbol using the same. According to an embodiment of the present invention, in a multiple input multiple output (MIMO) system using spatial multiplexing (SM), a receiver selects candidate vectors corresponding to a layer located at a last row among a plurality of rearranged layers, and sequentially ranks constellation dots of a next layer for each of the selected candidate vectors. Then, a plurality of arbitrary constellation dots are selected from the ranked constellation dots, accumulated costs of the arbitrary constellation dots are calculated, and a candidate vector is selected in correspondence with a constellation dot having a minimal accumulated cost.

Abstract: The present invention relates to a log-likelihood ratio calculation method, a transmitting signal detection method, and a receiver. The present invention estimates a channel on the basis of the received signal and rearranges a plurality of layers. Further, at the time of rearrangement of the layers, a symbol of a layer having the lowest reliability is considered for every constellation dot, and the successive interference for the remaining layers is removed corresponding to the constellation dots of the layer having the lowest reliability to set the transmitting symbol candidate vector. Furthermore, a log-likelihood ratio for every bit of the plurality of layers is calculated using the transmitting symbol candidate vector to decode the channel.

Abstract: The present invention relates to a method of calculating a log-likelihood ratio and a method of detecting a transmission signal. According to the present invention, when a transmission symbol candidate vector is detected on the basis of a received signal, a threshold value and an ML metric of each transmission symbol candidate vector are calculated and the ML metric that is larger than the threshold value is updated by the threshold value. Further, a log-likelihood ratio of the transmission signal bit is calculated using the updated ML metric and the threshold value, and a transmission signal is detected using the log-likelihood ratio.

Abstract: Disclosed is a method and apparatus for composing a received symbol signal modulated with a bit reflected Gray code into bit information. According to an embodiment of the present invention, a positive integer of the received symbol signal having bits is assigned according to the Gray mapping rule, and a sign is determined. A value that is indicative of an arrangement of the bits constituting the received symbol signal is calculated. A boundary value in at least one bit group consisting of the bits constituting the received symbol signal is acquired, and a difference from an absolute value of the received symbol signal is calculated. The received symbol signal is converted into information per bit using a value of the received symbol signal based on the positive integer and the determined sign, the value that is indicative of the bit arrangement, and the difference from the absolute value.

Abstract: The present invention relates to a method of detecting a space-time code in a mobile communication system. When detecting a space-time code B for a plurality of transmitting antennas, an ML (maximum likelihood) metric, which is generally calculated by using a specific structure of a matrix B, is defined as a new ML metric by reducing a variable of the ML metric. Two dependent sphere decoding processes are performed and an intersection of the decoding results is calculated, and a signal is detected from the ML metric. Therefore, since detection of the space-time code B for the plurality of transmitting antennas is performed by using the newly defined ML metric, an amount of matrix calculated can be reduced, and a calculation amount can be reduced by performing the two dependent sphere decoding processes. Further, since a detection order of symbols is changed according to a channel situation, it is possible to improve the performance of the system.

Abstract: Disclosed is an apparatus for acquiring initial frame timing in a communication system having a normalizer that calculates a normalized window power from powers of samples of received signal during a monitoring period, a cross power calculator that calculates a window cross power from cross powers of the samples during the monitoring period, and each cross power corresponds to multiplication of two of the samples, a divider that divides the window cross power by the normalized window power and outputs a metric for a sample corresponding to the monitoring period, and a peak-value detector that searches a sample having the maximum value among metrics for the samples of the received signals during a predetermined period, and the metrics are calculated by shifting the monitoring period, with a sample next to the sample searched by the peak-value detector being determined as a starting point of a frame.

Abstract: Disclosed are a row-vector norm comparison method and a row-vector norm comparison apparatus for an inverse matrix. A row-vector norm comparison apparatus includes: an input matrix processing module that receives and combines constituent elements of a matrix; a cofactor operation module that multiplexes the combination result of the constituent elements to calculate factors constituting an adjoint matrix; a square calculation module that squares the calculated factors; a summation module that selects a predetermined number of factors among the squared factors and sums the selected factors to calculate the norms of row vectors in an inverse matrix; and a norm comparison module that outputs a comparison result of the calculated norms of the row vectors.

Abstract: The present invention relates to a transmission symbol detection method in a multiple antenna system. In the present invention, when a channel matrix is estimated through channel estimation, a receiving side calculates a Q matrix and an R matrix through QR decomposition that is more simplified than a typical QR decomposition from an augmented channel matrix that includes the estimated channel matrix. In addition, the receiving side detects symbols having the minimum Euclidean metric by using the two matrixes, as transmission symbols.

Abstract: The present invention relates to a method of calculating a soft value and a method of detecting a transmission signal. The present invention estimates a channel on the basis of a received signal and rearranges a plurality of data streams. Further, a plurality of substitute vectors are selected from the rearranged data streams and a metric corresponding to each of the substitute vector is calculated. Further, a threshold value is calculated from a metric calculated for each of the substitute vectors and a soft value of each bit of a transmission signal is calculated from the metric and threshold value corresponding to each of the substitute vectors.

Abstract: The present invention relates to a method of calculating a log-likelihood ratio and a method of detecting a transmission signal. According to the present invention, when a transmission symbol candidate vector is detected on the basis of a received signal, a threshold value and an ML metric of each transmission symbol candidate vector are calculated and the ML metric that is larger than the threshold value is updated by the threshold value. Further, a log-likelihood ratio of the transmission signal bit is calculated using the updated ML metric and the threshold value, and a transmission signal is detected using the log-likelihood ratio.