• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.11 no.3
• /
• pp.17-22
• /
• 2011

In this paper, we analyze co-channel interference cancellation performance to be generated in multi-hop military communication system. First, remove interference using zero-forcing (ZF) and minimum mean square error (MMSE) scheme as interference cancellation methods, and then obtain additional diversity gain and improve interference cancellation performance by applying successive interference cancellation (SIC). We consider Rayleigh fading channel and system performance is analyzed as respect of bit error probability. From simulation results, we confirm MMSE improves significantly BER performance than ZF in multi-hop wireless network environment. It is also confirmed ZF and MMSE schemes applying SIC algorithm have better performance comparing to the existing schemes. Therefore, MMSE-SIC method can provide more reliable signal transmission in the multi-hop military communication system.

• Journal of Advanced Navigation Technology
• /
• v.15 no.3
• /
• pp.392-404
• /
• 2011

In this paper, we address the issue of joint detection schemes for uplink cellular system when base station cooperation is possible for multi-user detection in multi-cell scenario. The ZF, ML, MMSE and SIC detection are analyzed and evaluated as a conventional scheme. ML attains the optimal performance but the complexity increases exponentially, ZF/MMSE have simple structure but have poor detection performance and SIC has better performance but it has large complexity and potential of the error propagation. However, they need the increased decoder complexity as the number of iteration is increased. We propose a new joint ML and ZF/MMSE detection scheme, which combines the partial ML decoding and ZF/MMSE detection, in order to decrease the decoder complexity. Simulation results show that the proposed scheme attains same or a little bit better BER performance and expect reduced decoder complexity, specially in the case of large number of Base Station are cooperated each other.

• Korea Trade Review
• /
• v.42 no.1
• /
• pp.125-139
• /
• 2017

According to the US market research firm "Strategy Analytics(SA)", there is a sudden change of wind blowing in the global smart-phone market. In particular, several Chinese firms such as Huawei, Xiaomi and Oppo show a rapid growth in the pace of Chinese market, whereas other leading players like Apple and Samsung has slowly grown in China market. Therefore, this study will investigate the main antecedents of repurchase intention of smart phones in post-90th generation in China. In addition to this, the mediating effect of SIC will be analyzed. The results of the study are as follows; first, there is significant relationships among brand, individual experience and repurchase intention, on the other hand, there is no significant relationships between design, price, function factor and repurchase intention; second, SIC partially mediate the relationship between brand factors and repurchase intention. Based on the results targeted to post 90th generation in China, several implications are suggested for smart phone firms.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.2
• /
• pp.221-227
• /
• 2002

In this paper, in order to know the effect of the interference, we have analyzed the BER (Bit Error Rate) performance of the MUD(Multi-User Detector) employing HIC(Hybrid Interference Cancellation) scheme for the asynchronous WCDMA system based on 3GPP(3rd Generation Partnership Project) Spec. through the In this paper, in order to know the effect of the interference, we have analyzed the BER (Bit Error Rate) performance of the MUD(Multi-User Detector) employing HIC(Hybrid Interference Cancellation) scheme for the asynchronous WCDMA system based on 3GPP(3rd Generation Partnership Project) Spec. through the computer simulation. we have assumed Rayleigh fading channel. And we have compared its BER performance with SIC's(Successive Interference Cancellation) and with PIC's(Parallel Interference Cancellation), which are the representative schemes in the subtractive interference cancellation. From the results, it is shown that PlC or HIC is effective for high data-rate users and SIC of HIC for low data-rate users to eliminate the interference. Regardless of the data rate, it is reasonable to use the HIC structure for WCDMA system to satisfy all of users' services. The reason is that the SIC scheme in front of HIC can guarantee the performance of low power users to cancel the serious interference caused by the high power users, while PIC in the rear of it can guarantee the performance of high power users to cancel the interference caused by the low power users.

• The Journal of shipping and logistics
• /
• v.27 no.4
• /
• pp.719-746
• /
• 2011

This study attempted to analyse the results of investments from each individual ship investment company(SIC) in Korea which is operating under its ship investment company system. We analyzed investment result of ship investment company by means of Market Adjusted Return Method for measurement of abnormal return(AR) and cumulative abnormal return(CAR). Some implications from the results of this study are suggested. First, we find that the initial abnormal return of IPO, 30-day CAR and long-term CAR are not significantly different between A and B shipping fund management company. And then, the initial abnormal return of IPO and long-term CAR are not significantly different between newbuilding and secondhand ship SIC. But the 30-day CAR is significantly different between newbuilding and secondhand vessel SIC. Third, the 30-day CAR and long-term CAR are not significantly different between newbuilding and secondhand vessel SIC. But the 30-day AR is not significantly different between container and non-container ship SIC. Finally, newbuilding ship SCI is more stable than secondhand vessel SIC, and container ship SIC is more stable than non-container ship SIC in 3-month cumulative return over the past two and half years, from February 2008 to July 2011.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1996.05a
• /
• pp.51-51
• /
• 1996

• Journal of Advanced Navigation Technology
• /
• v.6 no.1
• /
• pp.17-26
• /
• 2002

In this paper, we have analyzed the BER (Bit Error Rate) performance of multi-user detectors employing SIC(Successive Interference Cancellation) and PIC (Parallel Interference Cancellation) which are the representative schemes in the subtractive interference cancellation. We have considered the MUD structure employing HIC (Hybrid Interference Cancellation) which combines SIC with PIC scheme, and then analyzed the BER performance. We have evaluated the BER performance of SIC and HIC schemes which execute the soft decision to generate the tentative data bit for the purpose of the interference cancellation in MAI and noise environments. Through the numerical analysis and computer simulation, it is shown that HIC can remove the effect of MAI more efficiently than the others, that improve the BER performance and increase the capacity of DS-CDMA systems regardless of the power control conditions. The reason is that the SIC scheme in front of HIC can solve the near-far problem caused by the imperfect power control and PIC scheme in the rear of it can improve the performance much more.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.3
• /
• pp.269-278
• /
• 2002

In this paper, we proposed and analyzed the performance of the partial SSPIC (Successive Serial Parallel Interference Cancellation ) scheme adopting modified successive serial interference cancellation (SIC) scheme. Modified partial successive serial cancellation (SIC) stage is used to effectively shorten interference cancellation delay. Performance is analyzed in Rayleigh fading channel with both perfect and imperfect channel estimation. From the results, proposed partial SSPIC I and II multiuser detectors can shorten effectively a detection delay at first SIC stage. The partial SSPIC type l detector outperformed the conventional concatenated SICPIC detector in both performance and capacity and type ll detector maintains similar performance. Proposed partial SSPIC multiuser detector can effectively improve the system performance without excessive detection delay.

• International Journal of Internet, Broadcasting and Communication
• /
• v.12 no.1
• /
• pp.67-72
• /
• 2020

The fifth generation (5G) mobile communication has an impact on the human life over the whole world, nowadays, through the artificial intelligence (AI) and the internet of things (IoT). The low latency of the 5G new radio (NR) access is implemented by the state-of-the art technologies, such as non-orthogonal multiple access (NOMA). This paper investigates a practical issue that in NOMA, for the practical channel models, such as fading channel environments, the successive interference cancellation (SIC) should be performed on the stronger channel users with low power allocation. Only if the SIC is performed on the user with the stronger channel gain, NOMA performs better than orthogonal multiple access (OMA). Otherwise, NOMA performs worse than OMA. Such the superiority requirement can be easily implemented for the channel being static or slow varying, compared to the block interval time. However, most mobile channels experience fading. And symbol by symbol channel estimations and in turn each symbol time, selections of the SIC-performing user look infeasible in the practical environments. Then practically the block of symbols uses the single channel estimation, which is obtained by the training sequence at the head of the block. In this case, not all the symbol times the SIC is performed on the stronger channel user. Sometimes, we do perform the SIC on the weaker channel user; such cases, NOMA performs worse than OMA. Thus, we can say that by what percent NOMA is better than OMA. This paper calculates analytically the percentage by which NOMA performs better than OMA in the practical mobile communication systems. We show analytically that the percentage for NOMA being better than OMA is only the function of the ratio of the stronger channel gain variance to weaker. In result, not always, but almost time, NOMA could perform better than OMA.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.6
• /
• pp.2221-2227
• /
• 2015

To arrest a frequency nadir, a stepwise inertial control (SIC) scheme generates a constant active power reference signal of a wind turbine generator (WTG) immediately after a disturbance and maintains it for the predetermined time. From that point, however, the reference of a WTG abruptly decreases to restore the rotor speed for the predefined period. The abrupt decrease of WTG output power will inevitably cause a second frequency dip. In this paper, we propose a modified SIC scheme of a doubly-fed induction generator (DFIG) that can prevent a second frequency dip. A reference value of the modified SIC scheme consists of a reference for the maximum power point tracking control and a constant value. The former is set to be proportional to the cube of the rotor speed; the latter is determined so that the rotor speed does not reach the minimum operating limit by considering the mechanical power curve of a DFIG. The performance of the modified SIC was investigated for a 100 MW aggregated DFIG-based wind power plant under various wind conditions using an EMTP-RV simulator. The results show that the proposed SIC scheme significantly increases the frequency nadir without causing a second frequency dip.