A Tight Upper Bound on Capacity of Intelligent Reflecting Surface Transmissions Towards 6G Networks

정규혁 한국인터넷방송통신학회 2022 Journal of Advanced Smart Convergence Vol.11 No.2

To achieve the higher network capacity and mass connectivity in the forthcoming mobile network, revolutionary technologies have been considered. Recently, an upper bound on capacity of intelligent reflecting surface (IRS) transmissions towards the sixth generation (6G) mobile systems has been proposed. In this paper, we consider a tighter upper bound on capacity of IRS transmissions than the existing upper bound. First, using integration by parts, we derive an upper bound on capacity of IRS transmissions under Rician fading channels and a Rayleigh fading channel. Then, we show numerically that the proposed upper bound is closer to Monte Carlo simulations than the existing upper bound. Furthermore, we also demonstrate that the bounding error of the proposed upper bound is much smaller than that of the existing upper bound, and the superiority of the proposed upper bound over the existing upper bound becomes more significant as the signal-to-noise ratio (SNR) increases.

Impact of Rician Fading on BER Performance on Intelligent Reflecting Surface NOMA Towards 6G Systems

정규혁 국제문화기술진흥원 2022 International Journal of Advanced Culture Technolo Vol.10 No.3

The commercialization of the fifth generation (5G) mobile systems has quested enabling technologies, such as intelligent reflecting surface (IRS) transmissions, towards the sixth generation (6G) networks. In this paper, we present a bit-error rate (BER) performance analysis on IRS transmissions in 5G non-orthogonal multiple access (NOMA) networks. First, we derive a closed-form expression for the BER of IRS-NOMA transmissions under Rician fading channels. Then, by Monte Carlo simulations, we validate the proposed approximate BER expression, and show numerically that the derived BER expression is in good agreement with Monte Carlo simulations. Furthermore, we also analyze the BER performance of IRS-NOMA networks under Rician fading channels with different numbers of reflecting elements, and demonstrate that the performances improve monotonically as the number of reflecting devices increases.

영양원 변화가 Kerosene 분해율 및 분해균주 성장에 미치는 영향

정규혁,Chung, Kyu-Hyuck 한국환경보건학회 1999 한국환경보건학회지 Vol.25 No.3

Bioremediation is the technology to harness nature's biodegradative capabilities to remove or detoxify pollutions that threaten public health as environmental contaminants. Composting may become one of major bioremediation technologies for treating soils contaminated with petroleum if the fate of contaminants during composting is better understood Most composting research of petroleum was primarily focused on removing contaminant by optimizing composting conditions. Accordingly, laboratory feasibility studies may be useful to establish a realistic basis in co-composting complex substrate such as petroleum hydrocarbons. The purpose of this study was to assess the optimal conditions of kerosene biodegradation following supplementation with nutrient amendments under simulated composting conditions. Although it increased the growth of bacterial consortium, addition of co-substrates 0.5%(w/v) such as acetic acid, citric acid, glucose, and malic acid was not beneficial. Combination of nitrogen and phosphorous source enhanced kerosene biodegradation and reduced VOC evolution. These results showed that kerosene was able to utilize in bioremediation technology.

가습기살균제 독성에 대한 도전과 미래

정규혁 환경독성보건학회 2016 한국독성학회 심포지움 및 학술발표회 Vol.2016 No.10

Correlated Intelligent Reflecting Surface and Improved BER Performance of NOMA

정규혁 한국인터넷방송통신학회 2022 International Journal of Internet, Broadcasting an Vol.14 No.3

Towards the sixth generation (6G) mobile networks, spectrum and energy efficiency of non-orthogonal multiple access (NOMA) transmissions in the fifth generation (5G) wireless system have been improved by intelligent reflecting surface (IRS) technologies. However, the reflecting devices of an IRS tend to be correlated because they are placed close on the surface each other. In this paper, we present an analysis on the correlated IRS in NOMA cellular networks. Specifically, we consider the bit-error rate (BER) performances for correlated-IRS in NOMA networks. First, based on the central limit theorem, we derive an approximate analytical expression of the BER for correlated-IRS NOMA systems, by using the second moment of the channel gain. Then we validate the proposed analytical BER by Monte Carlo simulations, and show that they are in good agreement. In addition, we also show numerically the BER improvement of the correlated-IRS NOMA over the conventional independent-IRS NOMA.

Performance Analysis for Weaker Channel User in Non-Uniform Source SSC NOMA with Novel BTS

정규혁 한국인터넷방송통신학회 2022 Journal of Advanced Smart Convergence Vol.11 No.1

Recently, to improve the performance of the strongest channel gain user in non-orthogonal multiple access (NOMA) with a non-uniform source and symmetric superposition coding (SSC), a novel bit-to-symbol (BTS) mapping have been proposed. However, only the performance of the user with the stronger channel gain was analyzed. Thus, we compare the bit-error rate (BER) of the new BTS scheme with that of uniform sources, especially for the user with weakest channel gain. First, we show that the performance of the novel BTS scheme for the user with weakest channel gain also improves, compared to that of the uniform sources. Furthermore, the signal-to-noise (SNR) gain of the new BTS scheme over the uniform sources is calculated. As a consequence, the novel BTS scheme would improve the performance of the user with weakest channel gain as well as that with the stronger channel gain for SSC NOMA with a non-uniform source.

BTS Based Improved BER for Stronger Channel User in Non-Uniform Source SSC NOMA

정규혁 한국인터넷방송통신학회 2022 International Journal of Internet, Broadcasting an Vol.14 No.1

In this paper, to improve further the bit-error rate (BER) performance of the stronger channel user in nonuniform source non-orthogonal multiple access (NOMA) with symmetric superposition coding (SSC), we propose a smart bit-to-symbol (BTS) mapping of SSC. First, the analytical expression for the total allocated power of the proposed BTS mapping scheme is derived, and then we show that the BER of the proposed BTS mapping scheme improves further, compared to that of the existing BTS mapping scheme. Moreover, based on the simulations, the signal-to-noise (SNR) gain of the proposed BTS mapping scheme over the existing BTS mapping scheme is calculated. In result, the proposed BTS mapping could be a candidate scheme for nonuniform source SSC NOMA with the SNR gain.

BER Performance Comparison for Intelligent Reflecting Surface in NOMA: Phase Shifts Perspective

정규혁 한국인터넷방송통신학회 2022 International journal of advanced smart convergenc Vol.11 No.3

As the sixth generation (6G) promising technique, intelligent reflecting surface (IRS) has recently attracted much attention. The IRS based wireless communication is expected to deploy the upcoming 6G mobile networks, to increase energy and spectrum efficiency in the fifth generation (5G) wireless networks. In this paper, we compare the bit-error rate (BER) performances for phase-shift schemes of IRS non-orthogonal multiple access (NOMA). First, we derive a BER expression for the equalizing phase-shift scheme in IRSNOMA networks. Then we compare the BER of the equalizing phase-shift scheme to that of the identical phaseshift scheme in IRS-NOMA networks, and show the BER improvement of the equalizing phase-shift scheme IRS NOMA over the identical phase-shift scheme IRS NOMA. Furthermore, we also validate the proposed analytical BER for the equalizing phase-shift scheme in IRS-NOMA by Monte Carlo simulations, and demonstrate that they well match each other.

영양원 변화가 Kerosene 분해율 및 분해균주 성장에 미치는 영향

정규혁 성균관대학교 약학연구소 1999 成均藥硏論文集 Vol.11 No.-

Bioremediation is the technology to harness nature's biodegradative capabilities to remove or detoxify pollutions that threaten public health as environmental contaminants. Composting may become one of major bioremediation technologies for treating soils contaminated with petroleum if the fate of contaminants during composting is better understood Most composting research of petroleum was primarily focused on removing contaminant by optimizing composting conditions. Accordingly, laboratory feasibility studies may be useful to establish a realistic basis in co-composting complex substrate such as petroleum hydrocarbons. The purpose of this study was to assess the optimal conditions of kerosene biodegradation following supplementation with nutrient amendments under simulated composting conditions. Although it increased the growth of bacterial consortium, addition of co-substrates 0.5%(w/v) such as acetic acid, citric acid, glucose, and malic acid was not beneficial. Combination of nitrogen and phosphorous source enhanced kerosene biodegradation and reduced VOC evolution. These results showed that kerosene was able to utilize in bioremediation technology.

On Power of Correlated Superposition Coding in NOMA

정규혁 한국전기전자학회 2020 전기전자학회논문지 Vol.24 No.1

We present the power of the correlated superposition coding (SC) in non-orthogonal multiple access (NOMA). This paper derives closed-form expressions for the total allocated power with the constant total transmittedpower. It is shown that the total allocated power is the function of a correlation coefficient. In result, thecorrelated SC NOMA should be designed with consideration of the correlation coefficient.