Abstract:
A soft-decision information generation method in MIMO(Multi-Input Multi-Output) system for reducing computational complexity and performance degradation is provided to reduce the computational complexity of a likelihood algorithm and to calculate LLR(Log-Likelihood Ratio) by inputting a channel decoder. A received vector y and a channel matrix H are inputted(102). The Hermitian of Q matrix is calculated reception vector z to a reception vector y(104). The l indicating the index about angular points on the M-ary constellation is initialized to 1. The candidate symbol vector of M is saved by using the transformed received vector z as described above about all points on the possible M-ary constellation(108,110).
Abstract:
본 발명은 부호화된 다중 입력 다중 출력(Multi-Input Multi-Output;MIMO) 시스템에서 로그 우도 비(Log-Likelihood Ratio;LLR) 계산시 필요한 후보 심벌 벡터의 개수를 줄일 수 있도록 한 연판정 정보 생성 시스템 및 방법에 관한 것으로, 주어진 채널 행렬에서 특정 순열에 따라서 열벡터들을 재배열하고 변형된 수신 벡터를 산출하고 병렬 판정 궤환 등화(HDFE) 방법으로 개의 후보 심벌 벡터를 구하는 단계; 구해진 후보 심벌 벡터들 중에서 한 개의 후보 심벌 벡터를 선택하여 해당하는 비트들 중 K개 비트를 산출하는 단계; 변형된 병렬 판정 궤환 등화(MHDFE) 방법으로 상기 산출된 개의 비트들에 대하여 반전된 비트들에 해당하는 개의 후보 심벌 벡터를 구하는 단계; 그리고 상기 구해진 심벌 벡터들( C + J) 에 대하여 각 원소들의 위치를 채널 행렬에 적용하였던 순열의 역으로 재배열하는 단계를 포함한다. 다중 안테나 기술, 연판정 (soft decision) 정보, 로그 우도 비 (LLR;log-likelihood ratio), V-BLAST (Vertical Bell labs LAyered Space-Time architecture)
Abstract:
A preamble symbol in an OFDM(Orthogonal Frequency Division Multiplexing) system, a method for designing the preamble symbol, and a method for acquiring timing/frequency synchronization are provided to generate various preamble patterns by differentiating short repetition patterns within long repetition patterns. A method of designing a preamble symbol includes the steps of: generating long repetition patterns of a length of P repeated K times in a temporal area by assigning preamble sequences to sub carriers in a frequency area and inverse-fast-Fourier-transforming of the preamble sequences(S21); generating short repetition patterns within the long repetition patterns by generating the short repetition patterns of a length L repeated M times in the temporal area and the short repetition patterns to a partial section within the long repetition pattern(S22); transforming a valid preamble symbol formed by the long repetition patterns and the short repetition patterns into a frequency area signal value by fast-Fourier transforming of the valid preamble symbol(S23); setting sub carriers in a protection area to 0 among the transformed frequency area signal values(S24); quantizing the frequency area signal(S25); and transforming the quantized signal into a temporal area signal by inverse-fast-Fourier transforming of the quantized signal(S26).
Abstract:
A vector norm approximation method, an apparatus thereof, and a receiver having the same are provided to shorten the time required to calculate a vector norm by approximating the vector norm through plural linear combinations, without a complicated operation. A vector norm approximation apparatus comprises absolute calculators, a maximum value searcher, and a linear combiner. The absolute calculators respectively obtain absolute values for the elements of a vector. The maximum value searcher selects the maximum value among the absolute values. The linear combiner, composed of two adders(102,104) and two multipliers(106,108), approximates a vector norm by linearly combining the maximum value with the sum of the absolute values.
Abstract:
송신안테나의 개수가 T이고 수신안테나의 개수가 N인 MIMO(Multi-Input Multi-Output) 시스템에서 수신 신호 벡터 y 에 대한 채널 복호기의 입력으로서 송신 비트들에 대한 연판정 정보를 생성하는 방법을 제공한다. 채널 행렬 H 에서 선택한 L(1≤L≤T) 개의 열벡터들 중에서 하나의 열벡터를 상기 행렬 H 의 왼쪽으로부터 T번째 열에 위치하는 열벡터와 자리를 서로 맞바꾸고, 상기 T번째 열에 위치할 열벡터가 선택된 상태에서 나머지 T-1개의 열벡터들에 대하여 순열을 결정하여 채널 행렬 H' 을 생성한다. 상기 채널 행렬 H' 에 대해 H' = Q'R' 와 같이 QR 분해(decomposition)를 수행한다. 상기 수신 신호 벡터 y 에 상기 행렬 Q 의 허미션(Hermitian) 행렬 Q H 를 곱하여 변형된 수신 벡터 z 를 구한다. 변조 지수가 log 2 M이고, 가능한 M-ary 성상 상에서의 모든 점들에 대해 상기 변형된 수신 벡터 z 를 이용하여 M개의 후보 심벌 벡터를 구한다.
Abstract:
무선 랜 시스템에서 심벌 타이밍 동기 방법을 개시한다. 상기 심벌 타이밍 동기 방법은 프리앰블에 해당하는 신호를 수신하는 단계, 및 상기 수신된 신호와 프리앰블 내 순환 프리픽스를 포함하는 기준 심벌과의 교차 상관값을 이용하여 심벌 타이밍을 추정하는 단계를 포함한다. 원래의 무선 랜 규격의 프리앰블 구조를 변경하지 않고 다중 경로 채널 환경 하에서 심벌 간 간섭을 최소화할 수 있다. 무선 랜, 심벌 타이밍 동기, 프리앰블, 교차 상관
Abstract:
PURPOSE: A calculation apparatus is provided to reduce complexity of a decoding process by efficiently approximating a Bessel function. CONSTITUTION: A channel log likelihood ratio calculation unit calculates a channel log likelihood ratio from a signal about a received encoded data. A decoder(230) estimates the data by operating an iterative decoding for the calculated channel log likelihood ratio. A function taking natural logarithm of a 0-th order modified Bessel function of the first kind is approximated to n-th order polynomial. A matching filter(210) outputs the signal which is filtered by receiving a signal transmitted from data transfer equipment.
Abstract:
A soft decision information generating system and a method thereof are provided to offer a method which calculates an LLR(Log-Likelihood Ratio) as a channel decoder input that is close to a maximum likelihood algorithm having high performance and low calculating complexity. A first transmission candidate symbol vector calculation unit performs HDFE(Hierarchical Decision Feedback Equalization) on the basis of channel signals and a reception signals in order to get first transmission candidate symbol vectors. A second transmission candidate symbol vector calculation unit performs the HDFE on the basis of the channel signal and the reception signal about the bits of the transmission candidate symbol obtained from the first transmission candidate symbol vectors in order to get second transmission candidate symbol vectors. An element order change unit(108) of the candidate symbol vector rearranges positions of each element about the symbol vectors as the reversed order applied to a channel matrix. An LLR(Log-Likelihood Ratio) calculation unit(109) calculates the LLR about the all bits by using the symbol vectors, and inputs the LLR into a channel decoder.
Abstract:
An iterative decoding device using SCR/SDR(Sign Change Ratio/Sign Difference Ratio) in a non-binary code and an operation method thereof are provided to regulate the number of iterative decoding times by utilizing SCR or SDR for extrinsic information for each symbol, extrinsic information of bits, and an approximate value of bit extrinsic information. In an iterative decoding device using SCR/SDR in a non-binary code, an iterative decoding execution unit(100) iteratively decodes the non-binary code received from a transmitter, by a unit of 2^n-ary n-tuple binary symbol by using extrinsic information generated from a first decoder(101), for a second decoder(102), and inputting soft output generated from the second decoder, to the first decoder again. An SCR/SDR calculating unit(110) calculates SCR/SDR indicating the change ratio of the code by using extrinsic information related to the 2^n-ary n-tuple binary symbol. An iterative decoding stop unit(120) stops an iterative decoding operation and finishes decoding if the computed SCR/SDR is over each critical value.