• International journal of advanced smart convergence
• /
• 제6권3호
• /
• pp.1-8
• /
• 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.

• Journal of Communications and Networks
• /
• 제12권6호
• /
• pp.605-615
• /
• 2010

Intercarrier interference (ICI) in orthogonal frequency division multiplexing (OFDM) systems, which causes substantial performance degradation in time-varying fading channels, is analyzed. An equivalent spreading code formulation is derived based on the analogy of OFDM and code division multiple access (CDMA) systems. Techniques as linear multiuser detection in CDMA systems are applied to suppress the ICI in OFDM systems. The performance of linear detection, measured using multiuser efficiency and asymptotic multiuser efficiency, is analyzed given the assumption of perfect channel state information (CSI), which serves as an upper bound for the performance of practical systems. For systems without CSI, time domain and frequency domain channel estimation based linear detectors are proposed. The performance gains and robustness of a linear minimum mean square error (LMMSE) filter over a traditional filter (TF) and matched filter (MF) in the high signal-to-noise ratio (SNR) regime are demonstrated with numerical simulation results.

• 한국통신학회논문지
• /
• 제38A권1호
• /
• pp.96-107
• /
• 2013

본 논문에서는 초광대역 통신시스템의 확산코드 정합필터링 방식이 서로 다른 다중 접속 방식에 따라 다중사용자 간섭신호의 전력 파라미터에 어떠한 영향을 미치는가에 대하여 개시한다. 보다 구체적으로, 다중 접속 시스템에 사용되는 확산코드 정합필터의 길이가 다중사용자 간섭신호의 평균전력, 최대전력, 그리고 최대전력 대 평균전력 비율에 미치는 영향을 분석하였다. 간단화된 환경에 대하여 이론적 분석을 수행하였고, 모의실험을 통하여 이를 검증하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 하계종합학술대회 논문집
• /
• pp.849-852
• /
• 1999

In this paper, the performance of DS/CDMA receiver is analyzed, which employs a cascaded interference canceller using a soft detection. The channels considered is characterized by the multipath fading which is one of the factors for the performance degradation in mobile communication systems. The idea behind the cancellation is that the co-channel interference can be regenerated at the receiver and is subtracted from the received signal. The numerical results show the improvement of BER can be obtained by the proposed cancellation scheme.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
• /
• pp.89-92
• /
• 2001

In this paper, adaptive multi-stage parallel interference cancellation (PIC) receiver is considered for a multi-rate DS-CDMA system. In each stage of the adaptive multi-stage PIC receiver, multiple access interference (MAI) estimates are obtained using the sub-bit estimates from the Previous stage and the adaptive weights for the sub-bit estimates. The adaptive weights are obtained by minimizing the mean squared error between the received signal and its estimate through a least mean square (LMS) algorithm. It is shown that the adaptive multi- stage PIC receiver achieves smaller BER than the matched filter receiver, multi-stage PIC receiver, and multi-stage partial PIC receiver for the multi-rate DS-CDMA system in a Rayleigh fading channel.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
• /
• pp.357-360
• /
• 2001

In this paper, we propose and evaluate a new interference cancellation method using low pass filtered data estimation method of the instantaneous decision sawnle obtained from each decision stage. With respect to the convergence to the optimal solution the superiority of the proposed method to parallel interference cancellation (PIC) referred as prevailing techniques is proved by its (asymptotic) spectral radius. Through the simulation under the various environment, we show the performance superiority of the IC scheme using proposed method to the PIC scheme. Furthermore, we show transcendence of the proposed method on the possibility of multirate transmission or multiple power scheduling and of performance in the various traffic environments.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2002년도 정기총회 및 학술대회
• /
• pp.3-8
• /
• 2002

A new Modem technique - 8-state Superposed QAM(8SQAM) - for use in power and bandwidth limited digital communication system is proposed. The premodulation baseband signal of the 8SQAM system is a double-interval(2Ts) raised cosine pulse superposed with weighted single-interval(Ts) raised cosine pulse. The performance of the 8SQAM, in a nonlinearly amplified multi-channel environment with additive white Gaussian noise(AWGN), inter-symbol interference(ISI), inter-modulation(IM) and adjacent channel interference(ACI), is analyzed via computer simulation. The simulation result shows that the 8SQAM outperforms 8PSK by about 1.6㏈ at BER=$1\times10^{-4}$ when HPA IBO is 1㏈ and channel Spacing, ${\Delta}F$ is 0.417fb.

• 한국산업정보학회:학술대회논문집
• /
• 한국산업정보학회 1997년도 추계학술대회 발표논문집:21세기를 향한 정보통신 기술의 전망
• /
• pp.407-415
• /
• 1997

In this paper, we apply a digital modulation scheme called Multi-Carrier CDMA (MC-CDMA) to the technique for cochannel interference cancellation using reference correlator, previously proposed. The cancellatoin method will be effective for reducing the interference components which are other users'signal components in a common channel, but fading effect of channel remains as the degrading factor of channel condition. For compensating it, MC-CDMA scheme is introduced to combat agianst the multipath fading. We analize above system and derive the average probability of error in AWGN and Rayleigh fading environment.

• 한국통신학회논문지
• /
• 제29권3A호
• /
• pp.257-265
• /
• 2004

MRC 다이버시티 수신 시스템에서 상호 독립적이고 동일한 전력을 갖는 동일 채널 간섭자들이 존재할 경우, Gray 부호화된 임의 직사각 QAM 신호의 성능을 분석하였다. 본 논문에서는 L개의 수신안테나를 갖는 MRC 수신 다이버시티 시스템에서 N명의 서로 독립적이고 동일한 나카가미 분포를 갖는 동일 채널 간섭자들의 신호가 수신되는 경우의 폐쇄형 (closed-form) 평균 비트 오류 확률 수식을 유도하였다. 이 수식은 수치 계산에 의해 쉽게 계산되는 초기하 함수를 이용하여 표현되었다.

• 한국통신학회논문지
• /
• 제40권10호
• /
• pp.2065-2067
• /
• 2015

본 논문에서는 Rolling Shutter CMOS 센서를 이용한 가시광 통신 시스템의 성능을 분석하였다. 성능분석을 위하여 ISI (Inter-symbol Interference)가 가시광통신에 미치는 영향을 분석하였다. 모의실험을 통하여 분석결과의 타당성을 검증하였다.