• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5497-5512
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• 2016

An improved optimal weights based on parallel interference cancellation algorithm has been proposed to cancel for interference induced by multi-user access satellite to ground uplink system. Due to differences in elevation relative motion between the user and the satellite, as well as access between users, resulting in multi-user access interference (Multi-user Access Interference, MUI), which significantly degrade system performance when multi-user access. By steepest gradient method, it obtained based on the MMSE criterion, parallel interference cancellation adjust optimal weights to obtain the maximum SINR. Compared to traditional parallel interference cancellation (Parallel Interference Cancellation, PIC) algorithm or serial interference cancellation ( Successive interference Cancellation, SIC), the accuracy of which is not high and too many complex iterations, we establish the multi-user access to the satellite to ground up link system to demonstrate that the improved WPIC algorithm could be provided with high accuracy and relatively low number of iterations.

• Journal of the Institute of Electronics and Information Engineers
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• 제52권5호
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• pp.23-32
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• 2015

The advanced receiver which can manage inter-cell interference is required to cope with the explosively increasing mobile data traffic. 3rd Generation Partnership Project (3GPP) has discussed network assisted interference cancellation and suppression (NAICS) to improve signal-to-noise-plus-interference ratio (SINR) and receiver performance by suppression or cancellation of interference signal from inter-cells. In this paper, we propose the novel hybrid receiver Full Suppression Cancellation (FSC) to reduce the interference from neighbor cell in backhaul system. The proposed receiver can suppress and cancel the interference by combining Interference Rejection Combining (IRC) with Successive Interference Cancellation (SIC). We perform the system level simulation based on 20MHz bandwidth of 3GPP LTE-Advanced system. Simulation results show that the proposed receiver can improve error rate and throughput of conventional system.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.177-181
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• 2002

In this paper, the cancellation or suppression of the feedback interference from Tx antenna using the same frequency is studied. The major problems on the wireless communication system using the same frequency or on-frequency repeater (OFR) are the coupling and isolation between Rx and Tx antenna. In order to increase the isolation between Rx and Tx antenna and to Prevent the self-oscillation of the receiver system, this paper is verified the possibility of the application of interference cancellation system and proposed the design method of the OFR using interference cancellation system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제16권3호
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• pp.253-262
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• 2003

In this paper, the interference cancellation system, which is used to cancel the feedback signal in the wireless communication system with the same frequency, is studied. The time varying feedback signal generated from transmitter antenna to receiver antenna reduces the performance of the receiver system. the interference cancellation system using adaptive feedback method(AF-ICS) is suggested to prevent the oscillation of the receiver system and maintain the maximum output power of the power amplifier by the reduction of time-varying feedback signal and also this paper conforms that the oscillation disappears from the output signal by cancellation of the feedback signal and the total output power is satisfied the system specification.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제39A권2호
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• pp.100-108
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• 2014

In this paper, we design SSD(simultaneous single band duplex) system using RF(radio frequency) cancellation and digital cancellation. we analyze characteristic of residual self-interference after RF Cancellation signal when error of phase shifter occur in RF cancellation. When phase shifter error of $0^{\circ}$, $0.5^{\circ}$, $1^{\circ}$ and $2^{\circ}$ occur in RF cancellation, residual self-interference signal power after RF cancellation is bigger than desired signal power of distant station. So, it is impossible to receive transmit data of distant station. but we confirm that it is possible to receive transmit data of distant station by digital cancellation with frame structure. Also, in digital cancellation with frame structure, if residual self-interference signal after RF cancellation is too large then LMS algorithm requires more time to estimate self-interference channel. That is, performance degradation occurs because self-interference channel estimation has not completed in estimation frame.

• Journal of the Institute of Electronics and Information Engineers
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• 제52권2호
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• pp.7-17
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• 2015

In this paper, we propose a single antenna SSD(simultaneous single band duplex) system using turbo equalizer. The proposed system communicates simultaneously on single band. That is the proposed system is full-duplex system. The proposed system uses balanced feed network circuit to improve isolation in single antenna structure. Also, the proposed system uses RF(radio frequency) cancellation and digital cancellation to cancel self-interference. Additionally, the proposed system uses turbo equalizer to equalize ISI(inter-symbol interference) by harsh multipath fading and to collect bit errors by residual self-interference signals. By using turbo equalizer, the proposed system guarantees QoS(quality of service). In this paper, we uses Simulink simulation program to analyze performance of the proposed system. The simulation results confirm that proposed system can communicate simultaneously by using balanced feed network, RF cancellation, digital cancellation and turbo equalizer in harsh multipath channel on single band.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제6권2호
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• pp.221-227
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• 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.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.47-50
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• 2000

In the Multirate DS/CDMA system based on VSL(Variable Spreading Length), the problem of the multiple access interference and effect similar to near-far effects in current system is generated. This problem can degrade performance of the system badly. Therefore, In this paper we proposed Hybrid Interference Cancellation to overcome this problems, Simulation result presents that the proposed Hybrid Interference Cancellation has the better performance than the conventional decorrelator, Parallel Interference Cancellation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제14권2호
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• pp.183-191
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• 2003

In this paper, the interference cancellation system, which is used to cancel the feedback signal In the wireless communication system with the same frequency, is studied. The time-varying feedback signal generated from transmitter antenna to receiver antenna reduces the performance of the receiver system. The interference cancellation system using adaptive feedback method(AF-ICS) is suggested to prevent the oscillation of the receiver system and maintain the maximum output power of the power amplifier by the reduction of time-varying feedback signal.

• Journal of information and communication convergence engineering
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• 제8권2호
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• pp.150-154
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• 2010

In this paper, the adaptive interference cancellation system (ICS) in order to cancel the feedback signal in the wireless communication system is proposed. We cancel the interference with the attenuation signal corresponding to the feedback signal and estimate the feedback signal by using Normalized Least Mean Square (NLMS) algorithm. The proposed scheme showed a better performance of interference cancellation in the measurement results.