• Title/Summary/Keyword: MMSE

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Application of selective MMSE scheme to the shifted TR for frequency selective channel (주파수 선택적 채널에서의 shifted TR 기반의 선택적 MMSE 기법 응용)

  • Cho, Jaewoong;Yoon, Misun;Lee, Bumsoo;Lee, Chungyong
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.560-562
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    • 2011
  • 본 논문에서는 송신단에서의 shifted TR 기법과, 이 것에 수신단에서의 선택적 MMSE 등화기를 추가한 통신시스템을 주파수 선택적 채널에서 실험해보고 이것이 shifted TR 기법만 사용했을 때와 비교하여 수신단의 선택적 MMSE 등화기가 성능에 어떤 영향을 끼치는지 관찰하였다. 이를 보호 구간 별로 실험 결과를 비교하였으며 수신단에 선택적 MMSE 등화기를 추가시켰을 경우, shifted TR 기법만을 사용했을 경우보다 비트 오차율 측면에서 성능의 이득이 있음을 확인하였다.

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Transmit Power and MMSE Receiver Filter Algorithm for Multi Access Points (다중 엑세스 포인트에서 전송전력과 MMSE 수신필터 알고리즘)

  • Oh, Changyoon
    • IEMEK Journal of Embedded Systems and Applications
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    • v.15 no.3
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    • pp.111-118
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    • 2020
  • We investigate the optimization problem of transmit power control and MMSE Receiver filter for multi access points environment. Previous work showed that increasing the number of access points decreases the transmit power consumption. Accordingly, transmit power control algorithm was developed in such a way that the transmit power is minimized, while each terminal meets Signal to Interference and Noise Ratio Requirement. In this work, we further reduce the transmit power consumption by optimizing the transmit power level and the MMSE receiver filter together. We showed that the proposed joint optimization algorithm satisfies the necessary and sufficient conditions to be standard interference function, which guarantees convergence and minimum transmit power consumption. We observed that the proposed algorithm outperforms the algorithm which only optimizes the transmit power.

Signal Detection Using Ordered Successive Interference Cancellation for Generalized Spatial Modulation Systems

  • Kim, Youngbeom;Kim, Sangchoon
    • International journal of advanced smart convergence
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    • v.6 no.3
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    • pp.1-8
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    • 2017
  • In this paper, an improved ordered block minimum mean squared error (OB-MMSE) detector for generalized spatial modulation (GSM) systems is presented. It is based on an ordered successive interference cancellation (OSIC) technique. Its bit error rate (BER) performance and computational complexity are compared with those of the corresponding original OB-MMSE detector. It is shown that the proposed OSIC-based OB-MMSE detector outperforms the OB-MMSE detector in terms of BER without noticeable complexity increase.

Improved SE SD Algorithm based on MMSE for MIMO Detection (MIMO 검파를 위한 MMSE 기반의 향상된 SE SD 알고리듬)

  • Cho, Hye-Min;Park, Soon-Chul;Han, Dong-Seog
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.3A
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    • pp.231-237
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    • 2010
  • Multi-input multi-output (MIMO) systems are used to improve the transmission rate in proportion to the number of antennas. However, their computational complexity is very high for the detection in the receiver. The sphere decoding (SD) is a detection algorithm with reduced complexity. In this paper, an improved Schnorr-Euchner SD (SE SD) is proposed based on the minimum mean square error (MMSE) and the Euclidean distance criteria without additional complexity.

A Correlation Between the Mini Mental State Examination-Korean Version and the Neuro-behavioral Cognitive Status Examination in Stroke Patients (뇌졸중 환자에서 한국판 간이 정신상태 판별검사(Mini Mental State Examination-Korean Version; MMSE-K)와 신경행동학적 인지상태검사(Neuro-behavioral Cognitive Status Examination; NCSE)의 상관관계)

  • Kim, Da-Hye;Kang, You-Il;Yun, Jin;Lee, Kyoung-Rok;Han, Ki-Chan;Chung, Hyun-Ae
    • PNF and Movement
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    • v.10 no.3
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    • pp.45-52
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    • 2012
  • Purpose : This study examines the relationship between the Mini Mental State Examination-Korean Version(MMSE-K) and the Neuro-behavioral Cognitive Status Examination(NCSE) in Stroke Patients. Methods : We studied sixteen people with stroke(7 males, 9 females) who were admitted to occupational therapy a participants were tested with the MMSE-K, the NCSE. Results : Correlation between the NCSE and the MMSE-K was significant in p<.05, p<.01. The result was orientation r=.652, memory r=.514, attention r=.417, calculation r=.839, comprehension r=.676, repetition r=.960, naming r=.683, construction r=.961, judgement r=.616. Conclusion : The MMSE-K and the NCSE are valid and useful measurement tools evaluating cognitive function of persons with stroke in Korea.

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A Time-Varying Modified MMSE Detector for Multirate CDMA Signals in Fast Rayleigh Fading Channels

  • Jeong, Kil-Soo;Yokoyama, Mitsuo;Uehara, Hideyuki
    • ETRI Journal
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    • v.29 no.2
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    • pp.143-152
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    • 2007
  • In this paper, we propose a time-varying modified minimum mean-squared error (MMSE) detector for the detection of higher data rate signals in a multirate asynchronous code-division multiple-access (CDMA) system which is signaled in a fast Rayleigh fading channel. The interference viewed by a higher data rate symbol will be periodic due to the presence of a lower data rate symbol which spans multiple higher data rate symbols. The detection is carried out on the basis of a modified MMSE criterion which incorporates differential detection and the ratio of channel coefficients in two consecutive observation intervals inherently compensating the fast variation of the channel due to fading. The numerical results obtained by the MMSE detector with time-varying detection show around 3 dB (M=2) and 6 dB (M=4) performance improvement at a BER of $10^{-3}$ in the AWGN channel, while introducing more computational complexity than the MMSE detector without time-varying detection. At a higher $E_b/N_0$, the proposed scheme can achieve a BER of approximately $10^{-3}$ in the presence of fast channel variation which is an improvement over other schemes.

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Interference Cancellation for Multiuser under the Environment of DS/CDMA System (DS/CDMA 시스템 환경에서 다중 사용자를 위한 간섭제거)

  • Kim, Hak-Chun;Lee, Byung-Kwan
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.10
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    • pp.3218-3225
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    • 2000
  • In this paper, the performance of the MMSE multiauser deteclor was analyzed with the SNR from the standpoint of the exproient, according to the multiuser, In was analyzed not only at the AWGN channel, but at the fading channel also. With the result of this test, the MMSE multiuser detector showed better performance of multi-connection interference in comparison with comon deterctors. However, its disadvantageis that the hardware turns out to be too complicated and that it requires too many calculations. Because of multi-connectioninterference that happens as a result of spreading code horizontally, the DS/CDMA system, which contatins the same frequency and time, turns out to thve interference according to the quality of the call and the number of users. In order to solve these problems, an adaptive MMSE multiuser detector is suggested. To increase the system's processing gain, the hardware's complexity can be reduced by establishing the number of taps wirhin the detector.

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Association between Cognitive Impairment and ADL of the Elderly in Rural Area (농촌 노인들의 인지기능장애와 일상생활 활동도와의 관련성)

  • Kim, Seok-Beom;Kang, Pock-Soo;Kim, Sang-Kyu
    • Journal of Preventive Medicine and Public Health
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    • v.32 no.1
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    • pp.65-71
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    • 1999
  • Objectives. The purpose of this investigation was to study the correlation between cognitive impairment and activities of daily living(ADL) In the elderly of rural area. Methods. The study population consisted of 210 elderly people aged 65 years and older, living in a district of Kyongju City. The cognitive impairment was measured with the Korean version of mini-mental state examination(MMSE-K) and newly constructed the Korean version of mini-mental state examination (K-MMSE). Bristol activities of dally living scale developed specifically to be used with people with dementia was used to measure ADL Results. The mean scores of both MMSE-K and K-MMSE were significantly different by sex groups and by .age groups, respectively(p<0.05). The mean scores of ADL were significantly different by age groups(p<0.01) not by sex groups. Among the 4 components of ADL(instrumental activities of daily living(IADL), self care, orientation, and mobility), the mean score of the orientation was significantly higher in men(p<0.01); and IADL, orientation and mobility components were significantly different by age groups(p<0.01). ADL correlated well with MMSE-K (r=0.54) and K-MMSE(r=0.52) and showed higher correlation in female (r=0.73, 0.71) than male(r=0.27, 0.29). IADL and orientation showed significant correlation with MMSE-K(r=0.52, 0.62) and K-MMSE(r=0.50, 0.63), respectively(p<0.01). Conclusions. In developing and establishing a care model for people with dementia in the community, both cognitive impairment and the activities of daily living(ADL) need to be considered.

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Performance of Interference Cancellation Scheme for Multihop Military Communication Systems (멀티 홉 군통신 시스템을 위한 간섭 제거 기법 성능 분석)

  • Kim, Yo-Cheol;Kim, Jin-Young
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.3
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    • pp.17-22
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    • 2011
  • In this paper, we analyze co-channel interference cancellation performance to be generated in multi-hop military communication system. First, remove interference using zero-forcing (ZF) and minimum mean square error (MMSE) scheme as interference cancellation methods, and then obtain additional diversity gain and improve interference cancellation performance by applying successive interference cancellation (SIC). We consider Rayleigh fading channel and system performance is analyzed as respect of bit error probability. From simulation results, we confirm MMSE improves significantly BER performance than ZF in multi-hop wireless network environment. It is also confirmed ZF and MMSE schemes applying SIC algorithm have better performance comparing to the existing schemes. Therefore, MMSE-SIC method can provide more reliable signal transmission in the multi-hop military communication system.

Pilot Assisted Channel Frequency Response Estimation for an OFDM System with a Comb-Type Pilot Pattern (빗 형태 패턴을 가지는 OFDM 시스템을 위한 파일럿 심볼 기반 채널 주파수 응답의 추정)

  • Kim, Youngwoong;Kim, Namhoon;Yoon, Eunchul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.6
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    • pp.333-342
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    • 2014
  • The pilot assisted channel frequency response (CFR) estimation schemes for an OFDM-based system with virtual subcarriers are analyzed under the assumption that pilot symbols are located according to a comb-type pattern in the OFDM block. In particular, as the minimum mean square error (MMSE) based scheme aiming to directly predict the channel impulse response and the MMSE based scheme aiming to suppress the leakage have not been clearly compared, by proving that the mean square errors (MSEs) of the latter scheme is always larger than that of the former scheme, this paper shows that the former scheme is superior to the latter scheme. Moreover, the impact of the number of pilots on the performances of the MMSE and least-square based channel estimation schemes are investigated. The performance analyses of the presented schemes are confirmed by computer simulation.