Abstract:
The present invention relates to a time synchronization apparatus of an OFDM based system and a method thereof improved an existing algorithm in order to have great time synchronization on many channels with multiple paths due to special environment such as an airport. The present invention can provide performance of a satisfactory level in all of AeroMACS seven channel models, in order to obtain the time synchronization as a metric result with having more sensitive characteristics than a previous method by using the result of calculation obtained using the multiple correlators for providing the performance of the great acquisition time synchronization in the channel models therewith. [Reference numerals] (110) Linear interpolation unit; (120) Control unit; (131) Correlator 1; (132) Correlator 2; (133) Correlator 3; (134) Moving average unit; (140) Estimating unit
Abstract:
The present invention relates to a fast fourier transform apparatus and method for multiple input output orthogonal frequency division multiplexing (MIMO-OFDM) system which can reduce the complexity of a hardware without the yield of the system to change as the minimum nontrivial multiplication uses the variable-length operation of 64~512 point while it supports the multiple channel input. The Institute of Electrical and Electronics Engineers (IEEE) 802 which can minimize the hardware complexity even when it's completely supporting 64/128/256/512 point variable-length operation through the mixed-radix (MR) algorithm, the twiddle factor (TF) nontrivial multiplication optimization, and a simplified data mapping, it can also support the variable band width of 20MHz, 40MHz, 80MHz, 160MHz while having data path of 8.@11ac. It has an effect that the performing apparatus of 11ac wireless LAN-system can be implemented in line with the optimum efficiency. [Reference numerals] (110) Data mapping module;(120) Butterfly module [R4BM];(130) Butterfly module [R2BM];(140) Butterfly module [R8BM1];(150) Butterfly module [R8BM2];(160) Data rearrangement module
Abstract:
PURPOSE: A time synchronizing apparatus and a method thereof for MIMO-OFDM based system are provided to increase resistance of multiple path transmission by executing time synchronization which searches for a starting point of a symbol. CONSTITUTION: A correlation unit operates a correlation value of a delayed reception signal and a test signal included in pre-emphasis. A power value is supplied to an operation unit(141) through a power operation unit(110). An operation unit(142) detects a boundary. The detected boundary information is supplied to an accumulation unit(150). The accumulation unit receives a correlation value through the correlation unit. [Reference numerals] (110) Power operation unit; (121,122) Self-correlation unit; (131,132) Mutual correlation unit; (141) F_mnc operation unit; (142) N_reg operation unit(f_mnc
Abstract:
PURPOSE: A fast Fourier transform device for a software definition wireless system based on MIMO(Multi Input Multi Output)-OFDM(Orthogonal Frequency Division Multiplexing) and a method are provided to support multiple channel input based on a MDC(Multi-path Delay Communicator) structure, thereby corresponding to a MIMO structure of various kinds. CONSTITUTION: A radix-3 butterfly module(560) selectively processes input data with a channel corresponding to received distance selection information. A first variable distance selection module is composed of multiplexers selecting one of the input data and output for the radix-3 butterfly module corresponding to the distance selection information. A data mapping module(510) reconstructs output data of the first variable distance selection module in parallel. Radix-2/2/4/2 butterfly modules(521-524) are successively arranged. [Reference numerals] (510) Data mapping module; (521) Butterfly module [R2BM1]; (522) Butterfly module [R2BM2]; (523) Butterfly module [R4BM1]; (524) Butterfly module [R2BM2]; (525) Butterfly module [R4BM1]; (526) Butterfly module [R2BM2]; (527) Butterfly module [R4BM2]; (528) Butterfly module [R2BM3]; (540) Clock distribution module; (550) Data rearrangement module; (560) Butterfly module [R3BM]; (AA) 1~4 channel data; (BB) Output
Abstract:
본 발명은 SDR(Software Defined Radio)을 위해 다채널 입력을 지원하면서 64~2048 포인트의 가변길이 연산을 최소의 복소승산기만 이용하도록 하여 구현 면적을 줄이며 저전력 동작이 가능하도록 한 다중입출력 직교주파수분할다중화 기반 소프트웨어 정의 무선 시스템을 위한 고속 푸리에 변환 장치 및 그 방법에 관한 것으로, 타겟 통신 방식에서 사용되는 가변 길이를 분석하여 얻어진 radix-2/2/4/2/4/2/4/2와 radix-3/4/2/4/2/4/2가 결합된 mixed-radix(MR) 알고리즘과 트위들 팩터(Twiddle Factor(TF)) 비단순 승산 최적화 및 단순화된 데이터 맵핑을 통해 64~2048 길이 중 현재 사용되는 모든 길이에 해당하는 64/128/256/512/1024/1536/2048-포인트 가변 길이 연산을 완벽하게 지원하면서도 하드웨어 복잡도를 최소화할 수 있어 저비용으로 무선랜, 모바일 와이맥스, LTE(Long Term Evolution), LTE-adva nced 통신 방식을 완벽하게 지원할 수 있는 효과가 있다.
Abstract:
본 발명은 시간 동기의 중요성이 큰 MIMO-OFDM 기반 시스템에서 짧은 훈련 신호만을 이용하여 오차 없이 시간 동기를 산출하도록 함으로써 동기 획득 정확도를 높이고 소요 시간을 줄일 수 있도록 한 다중입출력 직교주파수분할다중화 기반 시스템을 위한 시간 동기 장치 및 그 방법에 관한 것으로, 순환 지연 방식이 적용된 훈련 신호와 수신 신호간 상호 상관값의 결과에 다수개의 최대값이 발생 됨으로써 야기되는 시간 동기 오차를 산출된 상호 상관 값의 역순환 이동 후 합산하는 순환 지연 덧셈을 적용하여 보정하는 것으로 하나의 최대값을 얻을 수 있도록 함으로써 짧은 훈련 신호만을 이용하여 정확한 시간 동기를 얻을 수 있음을 물론이고 잡음이나 환경 변화에 강인하여 신뢰성을 높일 수 있는 뛰어난 효과가 있다.