• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.41-48
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• 2004

In this paper, we analyzed channel performance of PPM modulated UWB communication system in indoor radio fading environment that consider amplitude characteristic of channel. Fading channel considered various channel environments by fading index m utilizing Nakagami-m distribution model with data through an UBW radio signal experiment that announced in existing. Also, we improved performance of system that it is decreased in fading environment employing convolution encoding techniques.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1074-1084
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• 1999

In this paper the bit error probability of noncoherent M-ary FSK system is derived from the probability density function of the envelope of the received signal over a frequency-nonselective slowly m-distributed Nakagami fading channel. Also, the performance of coherent M-ray FSK system is theoretically analyzed, using union bound over the similar fading channel. Then we compare uncoded performance results for M-ary FSK and DPSK signals in Nakagami fading channel.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.699-705
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• 2001

It is considered DPSK modulation and the channel is modeled as multipath Nakagami fading type which has been recently taken as a general model in the communication environments in this paper. Most paper assumed that Nakagami fading index(m) of each branch of Rake receiver was fixed the same value in recent years. However, Nakagami fading index(m) of each branch of Rake receiver takes several value through communication environments. In this case, the branch ,which takes a small Nakagami fading index(m), exclude. So we can improve performance. We are considered phase error and analyzed wideband DS/CDMA cellular system. When nakagami fading index(m) takes voluntary value, we analyze BER of wideband DS/CDMA cellular system. Finally, When the branch, which takes a small Nakagami fading index(m), exclude, we analyze BER of wideband DS/CDMA cellular system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.477-484
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• 2003

In this paper, we compared and analyzed the influence of the fading index and the number of branch of diversity in the Nakagami-m fading channel environment when the MRC diversity and the hybrid SC/MRC are applied to the DS/CDMA system. We considered that the number of branches were 2,3, and 4, respectively and applied an individual diversity type according to the number of branches, when nakagami fading index(m) were 1 and 2. We found that when the Nakagami fading index m is small, that is to say, when fading is inferior, the application of a hybrid SC/MRC diversity Rake receiver is efficient; however, when the fading environment is good, the application of the MRC diversity Rake receiver is efficient. As a result, we verified that when the actual communication environment is inferior, the hybrid SC/MRC diversity that selects a strong signal to be received on an individual number of branches could replace the MRC diversity, as a method to achieve a similar performance by reducing the complexity of the system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.34-42
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• 2000

In this paper, the closed form expression for the average bit error probability(BER) is derived for diversity reception using an L-branch maximal ratio combining(MRC) system which has same fading index and different fading index. Also, the BER to have same average power and Nakagami m-distribution for a generalized selection combining(SC) is derived, whereby the signal with the largest amplitude is selected from the original diversity branches in the channel, the order statistics is applied. Especially, when L is 1 in a selective diversity, the derived expression leads to that of DPSK in which SC is not applied in Nakagami fading. Changing the diversity branch L and fading index m, we compare the performance of MRC and SC.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.5
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• pp.1010-1019
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• 2004

In this paper, we represent Nakagami-m fading channel as finite-State Markov Channel (FSMC) and analyze the performance of wireless communication system with varying the fading channel condition. In FSMC model, the received signal's SNR is divided into finite intervals and these intervals are formed into Markov chain states. Each state is modeled by a BSC and the transition probability is dependent upon the physical characterization of the channel. The steady state probability and average symbol error rate of each state and transition probability are derived by numerical analysis and FSMC model is formed with these values. We found that various fading channels can be represented with FSMC by changing state transition index. In fast fading environment in which state transition index is large, the channel can be viewed as i.i.d. channel and on the contrary, in slow fading channel where state transition index is small, the channel can be represented by simple FSMC model in which transitions occur between just adjacent states. And we applied the proposed FSMC model to analyze the coding gain of random error correcting code on various fading channels via computer simulation.

• Journal of the Korea Society of Computer and Information
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• v.6 no.3
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• pp.78-83
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• 2001

In this paper, we are considered Nakagami-m fading, which can model variable multipath mobile radio communication channel, in DS-CDMA system. System modeling using nakagami -m fading is suited for urban mobile communication channel with multipath. We used adaptive serial search PN code acquisition scheme and derived the detection probability($P_D$) and false alarm probability($P_FA$) which have influence on code acquisition time, over Nakagami-m fading. Detection probability($P_D$) and false alarm probability($P_FA$) are detection variable to decide PN code acquisition time and should use to calculate mean and variance. of acquisition time. From computer simulation, we analyzed mean and variance about PN code acquisition of fading channel. Then we can apply it to the H/W design of mobile communication.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.128-131
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• 2003

본 논문에서는 채널의 진폭 특성만을 고려한 실내 무선 페이딩 환경에서 PPM 변조된 UWB 통신 시스템의 채널 성능을 분석하였다. 페이딩 채널은 기존에 발표되었던 UWB 전파 실험을 통한 데이터를 바탕으로 Nakagami-m분포 모델을 이용하여 페이딩 지수 m에 따른 다양한 채널 환경을 고려하였다. 또한, 채널 성능을 평가하기 위해 신호대 잡음비, 페이딩 지수 m, 그리고 시스템 성능 파라미터인 펄스반복개수(Ns)를 이용하여 다양한 페이딩 환경에서의 UWB 시스템 성능을 분석하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.1
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• pp.9-18
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• 2003

In this paper, we analyzed the throughput of DS/CDMA system applying packet combining scheme combined with Type- I Hybrid ARQ scheme over AWGN channel and Nakagami fading channel with RAKE receiver. As the parameter for analysis, we used number of combined packet(L), number of diversity branch$({L_c})$, fading index(m), and length of packet(N), and used CRC-12 error detection code and (2,1,3) convolutional code. As a results, we found that throughput of system over Nakagami fading channel with RAKE receiver was superior to throughput over AWGN channel, and throughput of system decreases rapidly as channel degrades when number of combined packet(L) was increased. However throughput of system with the combining scheme was achieved even at low ${E_b}/{N_o}$. Also, we found that throughput of system was increased when fading index(m) and number of diversity branch$({L_c})$ were increased, but it was decreased when number of user(K) and length of packet(N) were increased.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1797-1804
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• 2011

In this paper, I analyzed array organization of MIMO channel antenna and effect of operation environment by evaluating average BER from linear Space-Time Block Code orthogonal design and suggests designing condition of MT antenna for improved BER and the fading index m. To analyze system performance, I used M-PSK and M-QAM modulation, and to use analysis equations I used integrated by Nakagami fading variable, non-integrated Nakagami fading variable. We can get the organization of channel array by using mathematical calculation on matrix. STBE BER performance will decrease as AOA spreading decrease and such loss can be compensated from extending antenna spacing, and changing array organization.