• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.3
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• pp.405-409
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• 2002

Recently, the FCC commissioners approved limited uses of UWB, and have promised to review the standards to explore the potential of more flexible standards and to address the operation of additional types of UWB operations and technology. In this paper we study performances of UWB communication system according to M-ary schemes with BCH code. And under the AWGN channel, we analysis and compare error probability, the number of M-ary schemes to the two methods that pulse position modulation and pulse amplitude modulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.139-147
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• 2003

In this paper we proposed system parameter values of M-ary PPM/TH(Pulse Position Modulation/Time Hopping) ultra-wideband systems having data rate of 100 Mbps for the frequency band, which is allocated by Federal Communications Commission(FCC). We also analyzed performance of the proposed system in the AWGN channels. According to the results of performance analysis, It is observed that available pulse duration is very limitative for this system. In case of constant data rate, if M and the pulse repetition numbers are increased, then the system performance is improved and the user number is decreased.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.365-373
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• 2003

This paper investigates the performance of M-ary pulse position modulation (PPM) multiuser ultra-wideband (UWB) communication systems in terms of symbol error rate (SER) over fading and additive white Gaussian noise (AWGN) channel. Based on Gaussian approximation for the multiple access interference, an expression for the signal-to-noise ratio (SNR) is derived for the UWB system. This expression is used to derive exact SER expressions for coherent UWB receivers. The effect of pulse selection on the SER of multiuser UWB system is studied. In addition to rectangular pulse, the 2nd derivative Gaussian waveform and Rayleigh pulses were considered. We show that the system capacity and/or SER performance can be significantly increased by using the monocycle pulse in fading channels.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.229-233
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• 2003

In this paper we theoretically analyze the probability of error for M-ary pulse position modulation (PPM) ultra-wideband (UWB) multiple access system using Gaussian monopulse. The optimum detection of UWB signals using M-ary orthogonal PPM in additive white Gaussian noise (AWGN) and multiple access interference (MAI) is considered, then receiver signal to noise power ratio (SNR) and upper bound fur the bit error rate (BER) are derived. Numerical results considering some practical parameters are presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1656-1662
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• 2005

This paper introduces M-PPAM(M-ary Pulse Position and Amplitude Modulation) architecture, combined PPM(Pulse Position Modulation) with PAM(Pulse Amplitude Modulation). Since M-PPAM can transmit several bits using one pulse, it is mon effective than PPM or PAM. Also, to obtain the same data transmission rate with PPM or PAM, M-PPAM can use a long pulse repetition period. This method will be able to use in the multi-path fading environment such as indoor condition. To accomodate multiple users, direct sequence technique is used. This paper has provided the modeling method of the M-PPAM DS-UWB receiver covering multi-user interference(MUI) with the Standard Gaussian Approximation under Gaussian channel. The performance of the receiver is simulated.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.3
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• pp.246-252
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• 2018

Recent studies have been received much attention on underwater laser communication, which is capable of high data rate. However, in underwater laser communication, distortions caused by absorption and scattering induced performance degradation. A typical way to improve performance is to apply channel coding technique. In the beginning of studies, simple methods such as RS and BCH coding techniques were applied. However, due to distance expansion and performance improvement, channel coding methods with low error probability such as LDPC coded method were applied. In this paper, we analyzed the performance according to the size of the code word N, the distance between the transceivers and the size of the M of the M-ary PPM modulation scheme. Simulation results show that parameter M of M-ary PPM is most effect on performance.

• Journal of Communications and Networks
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• v.10 no.3
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• pp.297-300
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• 2008

The capacity of ultra-wideband (UWB) systems in presence of narrowband interference (NBI) is studied. By appropriately modifying the Shannon capacity formula, an analytical expression for the capacity of M-ary pulse position modulation (PPM) signals in the presence of NBI is obtained. Performance evaluation results for the capacity of such signals as a function of the NBI carrier frequency and power are also presented.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.12-19
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• 2014

In this paper, an advanced UWB (ultra wideband) Rake receiving technique based on the statistical distribution model is studied in the M-ary TH-PPM system with multiple access interference (MAI). In order to improve the performance of the Rake receiver, the stochastic model, which can flexibly express the behavior of MAI-plus-noise, is required and the Laplace distribution and the generalized normal Laplace (GNL) model applied by the curtosis matching method are considered. The performance of Rake receiver based on each probability distribution is evaluated in the IEEE multipath fading channel and compared to that of the conventional Rake receiver. The suggested approach shows a superior BER performance than that of conventional Rake receiver.

• Journal of IKEEE
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• v.24 no.3
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• pp.814-820
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• 2020

In the M-ary DCSK system up to now, as M increases, the distance between constellation signal points becomes closer and performance deteriorates. we propose a hybrid modulation scheme based on PPM and DCSK to improve the BER performance. one part of the bit is modulated by the PPM and the other part by DCSK. Thus, the information bearing signal is modulated simultaneously according to the selected pulse position of the PPM determined by the information bit and the additional information bit. The analytical BER performance of the proposed plan is derived and verified by simulation. The results show that the proposed scheme outperforms conventional M-DCSK, code index modulation DCSK and rectified code index DCSK in additional white Gaussian noise and multipath Rayleigh fading channels.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.271-278
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• 2009

A new modulation scheme called multicoded-pulse position modulation (MC-PPM) is proposed for an ultrawideband (UWB) impulse radio communication system. The multicoded signal is generated by using several orthogonal codes for transmitting data simultaneously. Then, each multi-level value of the multicoded signal is converted to pulse position which results in not only an improved data rate, but also a processing gain in reception, delivering the power-efficient benefit of PPM and guaranteeing the low pulse energy for UWB systems. We notice that the modulation of multi-level values of the multicoded signal to pulse position is more efficient in terms of achievable data rate than the modulation of transmitting data based on other PPM schemes within given bandwidth and pulse energy. Therefore, as a performance measure, we focus on the achievable data rate (link capacity) of the proposed scheme and analyze it theoretically. Through simulation, we compare the link capacity of the MC-PPM scheme and other PPM schemes, such as M -ary PPM and multiple PPM. With the fixed bandwidth and same pulse energy condition, the UWB system based on the proposed MC-PPM scheme shows good link capacity and an increased data rate as L increases, which is contrary to other PPM schemes.