• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.8 no.4
• /
• pp.342-353
• /
• 1997

This paper presents an analytical evaluation of a hybrid direct-sequence/slow frequencyhopped code division multiple-access (DS/SFH-CDMA) system employing noncoherent M-ary frequency shift keying(MFSK) modulation in a multiple Nakagami fading (m) environment. Multipath interference (MPI) and multi-access interference (MAI) is taken into account and the spectral efficiency is calculated for uncoded as well as channel coding systems. Predetection multipath maximal ratio combining (MRC) diversity in conjunction with interleaved channel coding (Hamming(7,4) code, BCH(15, 7) code and RS (7, 4), (15, 9)) code ) is employed for improving the bit error rate (BER) performance. The BER of noncoherent hybrid system is obtained using a Gaussian interference approximation.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.8
• /
• pp.3585-3601
• /
• 2016

The error rate performance of circularly distributed antenna system is studied over Nakagami-m fading channels, where a dual-channel receiver is employed for the quadrature phase shift keying signals detection. To mitigate the Co-Channel Interference (CCI) caused by the adjacent cells and to save the transmit power, this work presents remote antenna unit selection transmission based on the best channel quality and the maximized path-loss, respectively. The commonly used Gaussian and Q-function approximation method in which the CCI and the noise are assumed to be Gaussian distributed fails to depict the precise system performance according to the central limit theory. To this end, this work treats the CCI as a random variable with random variance. Since the in-phase and the quadrature components of the CCI are correlated over Nakagami-m fading channels, the dependency between the in-phase and the quadrature components is also considered for the error rate analysis. For the special case of Rayleigh fading in which the dependency between the in-phase and the quadrature components can be ignored, the closed-form error rate expressions are derived. Numerical results validate the accuracy of the theoretical analysis, and a comparison among different transmission schemes is also performed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.4
• /
• pp.553-564
• /
• 2000

In this thesis, mobile communication channel with multi-path fading which is major factor of performance degradation of DS-CDMA system has been considered. An MRC diversity and error correcting coding technique have been used to improve performance of MFSK-MDPSK/DS-CDMA system. The MFSK-MDPSK/DS-CDMA system performance has been obtained quantitatively by the numerical analysis. the modulations under consideration are noncoherent M-ary frequency shift keying(MFSK) and an MFSK based joint frequency phase modulation utilizing MFSK/DS-CDMA and MDPSK-DS-CDMA systems the MFSK-MDPSK/DS-CDMA system obtain a better performance . Also, the error performance of MFSK-MDPSK/DS-CDMA system in Nakagami fading environments is improved by increasing the number of diversity branch and coding gain.

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

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1984.10a
• /
• pp.37-42
• /
• 1984

In this paper, the error rate equation of MSK system through the Nakagami's m-distribyted fading channel has been derived in the interference and inpulsive noise invironments. The evaluated performances are shown and discussed in terms of carrier-to-noise power ratio, carrier-to-interferer power ratio, fading figure, and impulsive indexes.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.11C
• /
• pp.1070-1076
• /
• 2003

This paper presents and analyses the exact and general closed-form expression for the average bit error probability of M-ary square quadrature amplitude modulation (QAM) for maximal ratio combining (MRC) diversity reception in frequency-nonselective Nakagami-m fading. An L-branch Maximal ratio combining diversity technique with independent or correlated fading cases is considered. Numerical results demonstrate the error performance improvement by employing with the use of MRC diversity reception. The new expressions presented here can offer a convenient way to evaluate the performance of an arbitrary square M-W square QAM with an MRC diversity combiner for various cases of practical interest.

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

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.9
• /
• pp.4295-4316
• /
• 2018

In this paper, the performance of non-orthogonal multiple access (NOMA) dual-hop (DH) amplify-and-forward (AF) relaying networks is investigated, where Nakagami-m fading channel is considered. In order to cover more details, in our analysis, the transceiver hardware impairments at source, relay and destination nodes are comprehensively considered. To characterize the effects of hardware impairments brought in NOMA DH AF relaying networks, the analytical closed-form expressions for the exact outage probability and approximate ergodic sum rate are derived. In addition, the asymptotic analysis of the outage probability and ergodic sum rate at high signal-to-noise ratio (SNR) regime are carried out in order to further reveal the insights of the parameters for hardware impairments on the network performance. Simulation results indicate the performance of asymptotic ergodic sum rate are limited by levels of distortion noise.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.7A
• /
• pp.748-755
• /
• 2004

In this paper, the hybrid SC/MRC technique was applied to the MC/DS-CDMA system in the Nakagami-m multi-path fading environment. The applied scheme was compared with other cases when the MRC technique was applied and then performances were analyzed. The result of analysis showed that the performance of the applied system, whose number of branches (L) for the input diversity of each carrier wave was 3 and かme selected number of branches ( Lc) was 2, was better than that of the MRC technique when the Lc of the MRC technique was 2. The performance of the applied system was lower than that of the MRC technique, then the Lc of the MRC technique was 3. However, as the fading index was lowered, which means the telecommunication environment deteriorated, the performance of the hybrid SC/MRC-(2/3) diversity technique when Lc of MRC technique was 3, was almost the same as that of the MRC technique. The hybrid SC/MRC-(2/3) diversity technique shows a similar performance to that of the MRC technique, when the Lc of the MRC technique was 4. Therefore, it was confirmed that the MC/DS-CDMA system could reduce complexity and achieve similar performance to that of the MRC by applying the hybrid SC/MRC technique, which utilized the advantages of the SC technique and high performance of the MRC scheme, rather than the MRC diversity technique that requires bit synchronization, frequency of fading, and phase synchronization for every diversity branch.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.12
• /
• pp.5129-5148
• /
• 2016

In this paper, the average bit error probability (ABEP) performance of the incremental-selective decode-and-forward (ISDF) relaying mobile-to-mobile (M2M) cooperative networks over N-Nakagami fading channels is investigated. The exact ABEP expressions are derived, and the power allocation problem is formulated.The derived ABEP expressions are verified by Monte Carlo simulations. The simulation results showed that the propagation parameters, such as the fading coefficient, and the power-allocation parameter, have a significant influence on the ABEP performance.