• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.337-344
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• 2011

In this paper, a multiple-input and multiple-output (MIMO) spatial multiplexing (SM) relay system is studied in a bit error rate (BER) sense, where every node is deployed with multiple antennas. In order to efficiently use the limited power resource, it is essential to optimally allocate the power to nodes and antennas. In this context, the power allocation (PA) algorithm based on minimum BER (MBER) for a MIMO SM relay system is proposed, which is derived by direct minimization of the average BER, and divided into inter-node and inter-antenna PA algorithm. The proposed scheme outperforms the conventional equal power allocation (EPA) algorithm without extra power consumption.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.486-492
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• 2002

In this paper. we presented 1 & 2 dimensional minimum mean-squared-error (MMSE) equalization scheme in a digital holographic data storage system to improve bit-error-rate (BER) and to mitigate inter-symbol interference (ISI) which were generated during the data storage and retrieval processes. We showed experimentally for ten data pages retrieved from the holographic storage system that BER and signal-to-noise ratio (SNR) were improved by adopting MMSE equalization.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.457-459
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• 2005

In this paper the BER consideration of a quadrature receiver that has an autocalibration method is considered. The analysis is based on the derivation of the statistical characteristics of the imbalances in gain and phase between in-phase and quadrature components that may cause severe performance degradation of the receiver. The density. mean and variance functions of the estimates of gain and phase imbalances are discussed. Then it is shown that the estimates are asymptotically minimum variance unbiased with respect to the integration time in sampling. A brief consideration on the BER calculation follows.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.42-49
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• 2016

This paper proposes a low-complexity generator which finds the first two minimum values using bit-serial scheme. A low-complexity generator is an important part for low-area LDPC decoders based on the min-sum decoding algorithm because the hardware complexity of generators utilizes a significant portion of LDPC decoders. To reduce hardware complexity, bit-serial LDPC decoders has been studied. The generator of the existing bit-serial LDPC decoders can find only the first minimum value, and thus it leads to a BER performance degradation. The proposed generator using bit-serial scheme finds the first two minimum values. Hence, it can improve the BER performance. In addition, the area-time complexity of the proposed generator is lower than those of the existing generators finding the first two minima.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1161-1168
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• 2010

The FHSS(Frequency Hopping Spread Spectrum), in which a transmitter changes its carrier frequency according to a certain hopping pattern, is widely used in the military communication system, since it is highly resistant to deliberate Jamming. However, the difference of BER performance of satellite communication system which using the different modulation scheme and Jamming model was not studied. Thus, in this paper, we consider PBNJ(Partial-Band Noise Jamming) and WPBJ(Worst case Partial-Band noise Jamming) as Jamming models, and evaluate BER(Bit Error Rate) performances of NC-MFSK(Non-Coherent M-ary Frequency-Shift Keying), SDPSK(Symmetric Differential Phase-Shift Keying), and GMSK(Gaussian filtered Minimum-Shift Keying) modulation schemes. Based on the results, we suggest the best transmission method for each condition.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.29-34
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• 2011

In this paper, we propose and analyze the equalizer schemes, zero-forcing (ZF) and minimum mean square error (MMSE) in power line communication (PLC) system for automatic meter reading (AMR). For efficient implementation of AMR system with PLC, effects of impulsive noise and multipath channel should be mitigated. To overcome these effects, the above equalizer schemes are employed. System performance is evaluated in term of bit error rate. From simulation results, it is confirmed that the equalizer can significantly improve bit error rate (BER) performance in PLC system, and MMSE equalizer provides better performance than ZF scheme. The results of this paper can be applied to AMR system as well as various smart grid services using PLC.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.1
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• pp.76-82
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• 2010

In this paper, we analyze the performance of the block linear MMSE equalization for OFDM systems in doubly selective channels by computer simulations. The block linear MMSE equalization shows somewhat unusual BER characteristics in that the BER curve drops at first as SNR increases but then rises up as SNR increases further beyond some point. In this paper, we investigate the BER characteristics of the block linear MMSE equalization by analyzing the condition number of the coefficient matrix in the linear system involved in the equalization process, and propose a new method to avoid the BER performance degradation at high SNR.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.8
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• pp.2157-2169
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• 2023

In order to handle the problem that puncture patterns will change the position distribution of original information bits and frozen bits in polar codes, which affects performance of puncture polar codes further, a minimum row weight and polar spectrum based puncture polar codes construction algorithm (called PA-MRWP) is proposed in this paper. The algorithm calculates row weight of generator matrix and sorts the row weight in ascending order first. Next, the positions with the minimum row weight are selected as initial puncture positions. If the rows with the same row weight cannot all be punctured, polar spectrum based auxiliary puncture scheme is used. In sub-channels with the same row weight, rows corresponding to the polarized sub-channels with higher reliability are selected as puncture positions to construct puncture vector, and the reliability is calculated based on polar spectrum. It is actually a two-step selection strategy, the proposed minimum row weight puncture (MRWP) algorithm is used for primary selection and polar spectrum based auxiliary puncture is used for adjustment. Simulation results show that, compared with worst quality puncture (WQP) algorithm, the proposed PA-MRWP algorithm and Gaussian approximation-aided minimum row weight puncture (GA-MRWP) algorithm provide gains of about 0.46 dB and 0.29 dB at bit error rate (BER) of 10^-4, respectively when code length N=400, code rate R=1/2. In addition, the proposed puncture algorithms improve the BER performance significantly with respect to quasi-uniform puncture (QUP) algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4C
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• pp.462-467
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• 2007

This paper proposes Minimum Distance Searching Algorithm (MDSA) which reduces the computational complexity (CC) of the ML, the kind of Spatial Multiplexing (SM) MIMO system. The MDSA searchs candidate symbols with a starting symbol, which is called reference bits. We used the linear receiver of MIMO techniques to find a starting symbol. The MDSA searchs the shortest path to a transmitted symbol using reference bits and Minimum Distance(MD) concept. The CC of MDSA is reduced to the 0.21% to the ML as the transmit antennas is 4 in 16QAM. The simulation result shows the BER of MDSA is nearly same to the BER of ML as the transmit antennas is 2 and the receive antennas is 3 in 16QAM and slightly degraded to the BER of ML as the transmit antennas is 4 and the receive antennas is 6 in QPSK.

• Journal of the Optical Society of Korea
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• v.7 no.3
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• pp.202-206
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• 2003

In this paper, minimum mean-squared-error(MMSE) and blind equalization schemes were employed to improve bit-error-rate(BER) and to reduce inter-symbol interference(ISI) generated during storage and retrieval processes of two-dimensional data in a digital holographic data storage system. We explained methods for designing and applying MMSE and blind equalization to improve BER in a digital holographic data storage system. From experimental evaluations, we compared the BER performances of MMSE and blind equalization and we showed that the BER performances of MMSE and blind equalization were improved significantly compared with those before equalization.