• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.6
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• pp.951-958
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• 1999

Multicarrier modulation or orthogonal frequency division multiplexing(OFDM) is a promising technique for mobile communications systems, since it has a strong immunity to multipath fading without employing complicated adaptive equalization. In this paper, performance of MC DS-CDMA/MPSK(multi-carrier direct sequence-code division multiple access/mary phase shift keying) and DS-CDMA/MPSK(direct sequence-code division multiple access/mary phase shift keying) with coherent detection for a CDMA system over Nakagami fading channel analysis. For a given bandwidth, it is shown that MC DS-CDMA/MPSK eventually outperforms DS-CDMA MPSK with random sequences.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.352-357
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• 2000

The symbol error probability for the coherent detection of MPSK signals in additive white Gaussian noise(AWGN) can be evaluated exactly for M=2 and M=4. The MPSK symbol error probability bounds obtained in the past are simple to calculate, but not accurate. More recently, very tight bounds have been proposed, but they are complex to calculate. In this paper to obtain a simple and accurate lower bound for coherent MPSK symbol error probability in AWGN, we consider the symbol error probability for MPSK in Nakagami fading case first. Then as the Nakagami fading index m approaches to infinity, we obtain the symbol error probability for the MPSK in AWGN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9C
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• pp.831-839
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• 2006

In this paper, we present an exact and general expression involving two-dimensional Gaussian Q-functions for the bit error rate (BER) of hierarchical MPSK with I/Q phase and amplitude imbalances over an additive white Gaussian noise (AWGN) channel. First we derive a BER expression for the k-th bit of hierarchical 4, 8, 16-PSK signal constellations when Gray code bit mapping is employed. Then, from the derived k-th bit BER expression, we present the exact and general average BER expression for hierarchical MPSK with I/Q phase and amplitude imbalances. This result can readily be applied to numerical evaluation for various cases of practical interest in an I/Q unbalanced hierarchical MPSK system, because the one- and two-dimensional Gaussian Q-functions can be easily and directly computed usinB commonly available mathematical software tools.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2696-2705
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• 1997

An exact experssion for the average symbol error rate(SER) of L-order selection diversity for MPSK signals in a frequency-nonselective slowy m-distributed Nakagami fading and additive white Gaussian noise(AWGN) is determs of finite sums is obtained. To derive the SER of MPSK signals with selection combining, the new expression of pdf is introduced and many other mathmatical methods are used. When fading index m is 1, the derived exppression lead to those of MPSK with selection combining in Rayleight fading channels. The results show that the error probability decreases as the order of diversity increases.

• ETRI Journal
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• v.28 no.6
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• pp.793-795
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• 2006

When quadrature error exists, the shape of the M-ary phase shift keying (MPSK) signal constellation becomes skewed-elliptic. Each MPSK symbol takes on a different symbol error probability (SEP) value. The analytical results presented thus far have been derived from studies which examined the SEP problem assuming that the SEP of each MPSK symbol is equally likely; therefore, those results should not be treated as offering a complete solution. In this letter, we present a new and more complete solution to the SEP problem of MPSK by relaxing the above assumption and finding the expressions for the average as well as individual SEP in the presence of quadrature error.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.375-380
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• 2009

Bit error rate(BER) performance of each bit for hierarchical M-ary phase shift keying(H-MPSK) modulation scheme is changed according to the phase parameters. Thus, a method to find the phase parameters appropriate to the requests of the system is needed. In this paper, we propose a method to obtain the phase parameters from an approximate approach of BER for H-MPSK and verify a validity of the proposed method through the previously provided expression for analyzing an exact error probability of H-MPSK.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.3
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• pp.55-67
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• 1995

The error rate equations of MPSK and DS/MPSK radio signals transmitted through the m-distributed fading channel in Gaussian noise and tone interference environments have been derived. Using the derived equations, the error rate performance is evaluated and shown as functions of carrier-to-noise ratio, carrier-to-interference ratio, processing gain, fading index and the number of diversity branches. The derivation has been done for two cases. The first case assumes that only the signal is undergoing the influence of fading, and the second case assumes that both signal and interference are undergoing the influence of fading simultaneously. From the obtained results, we have known that the error performance of MPSK signal is improved by using diversity technique and direct sequence spread spectrum technique even in a fading environment. Also comparing the error rate performance of two cases, the latter is worse than the former.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.782-790
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• 1999

In this paper, we propose an adaptive trellis-coded Multiple Quadrature Amplitude Modulation(ATCMQAM) applying MQAM as the modulation scheme in the conventional ATCMPSK (Adaptive trellis-Coded Multiple Phase Shift Keying) for slowly varying Rayleigh fading channels. The proposed system adaptively controls the coding rate combined with modulation level of pragmatic approach to trellis-coded modulation according to the instantaneous fading channel conditions, and employs MQAM as modulation scheme.Results by computer simulation show that the proposed adaptive model using MQAM can realize higher quality transmission with the improvement more than 0.5 ~ 1bit in average bit rate. And there is a coding gain of 2-5dB, depending on the high SNR value, compared with the conventional adaptive model employing MPSK.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.19-24
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• 1998

In this paper, a new closed form expression for the average symbol error rate(SER) of generalized selection combining(SC), whereby the two(three) signals with the two(three) largest amplitudes are combined from the original diversity branches in the channel, for MPSK signals in a frequency-nonselective slowly m-distributed Nakagami fading channel is derived. In order to analyze the error performance for a generalized SC, the Order-Statistics is applied. To derive the SER of MPSK signals with SC, the new expression of pdf is introduced and many other mathematical methods are used. Comparing the derived SER with that of MRC, we find adequate diversity branch number from total Lth-order diversity branches.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.4
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• pp.332-341
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• 1997

In this paper, we propose an adaptive trellis-coded Multipe Quadrature Amplitude Modulation (ATCMQAM) for slowly varying Rayleigh fading channels. The proposed system adaptively controls the coding rate combined with modulation level of pargmatic approach to trellis-coded modulation according to the instantaneous fading channel conditions, and employs MQAM as modulation scheme. Results by computer simulation show that the proposed adaptive model using MQAM can realize higher quality transmission with the improvement more than 0.5~1 bit in average bit rate, and there is a coding gain of 2~5 dB, depending on the high SNR value, compared with the conventional adaptive model employing MPSK.