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SSD(Simultaneous Single Band Duplex) System Using RF Cancellation and Digital Cancellation (RF Cancellation과 Digital Cancellation을 사용한 SSD(Simultaneous Single Band Duplex) 시스템)

  • An, Changyoung;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.2
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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.

Linear versus Non-linear Interference Cancellation

  • Buehrer, R.Michael;Nicoloso, Steven P.;Gollamudi, Sridhar
    • Journal of Communications and Networks
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    • v.1 no.2
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    • pp.118-133
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    • 1999
  • In this paper we compare linear and non-linear inter-ference cancellation for systems employing code division multi-ple access (CDMA) techniques. Specifically, we examine linear and non-linear parallel interference cancellation(also called multi-stage cancellation) in relationship to other multiuser detection al-gorithms. We show the explicit relationship between parallel inter-ference cancellation and the decorrelator (or direct matrix inver-sion). This comparison gives insight into the performance of paral-lel interference cancellation (PIC) and leads to vetter approaches. We also show that non-linear PIC approaches with explicit chan-nel setimation can provide performance improvement over linear PIC, especially when using soft non-linear symbol estimates. The application of interference cancellation to non-linear modulation techniques is also presented along with a discussion on minimum mean-squared error(MMSE) symbol estimation techniques. These are shown to further improve the performance of parallel cancella-tion.

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A Study on the Cost Estimation in Case of Termination in the Building Construction Contract (건축공사 계약해지에 따른 비용산정에 관한 연구)

  • Lee, Ho-Il;Choi, In-Sung
    • Journal of the Korea Institute of Building Construction
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    • v.3 no.2
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    • pp.95-102
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    • 2003
  • Financial difficulties and claims frequently stop construction works and cause subsequent contract cancellations. However, as the criteria to assess costs have not been established, many cases of legal disputes over the assessment of cancellation costs are taking place and the concerned parties are suffering the loss of time and money. Therefore, the present research aimed at developing a rational and systematic model of cancellation cost assessment following the cancellation of contracts. The research was carried out in the following methods and scopes. 1 ) The research was focused on the assessment of fair cancellation costs from constructors' side for contracts cancelled by any causes for which the owners have liability. 2) To obtain basic materials about cancellation cost assessment methods, contracts, claims, contract cancellations and construction-related laws at home and abroad were examined. 3) A cost assessment model was developed for systematization and efficient operation of cancellation cost assessment, and the reliability and efficiency of the proposed model was verified through a case study. The conclusions drawn from the research are as follows. The importance of the cancellation cost assessment model was confirmed as, using the cancellation cost assessment model, direct cancellation cost and indirect cancellation cost could be assessed systematically, the number of disputable items could be reduced because reasonable evidences of actual spending were presented, and the loss of constructors could be minimized because systematic and rational cost assessment became possible for many disputable cases of indirect cancellation cost, which the constructors had been unable to prove so far though having spent.

ON CANCELLATION IDEALS

  • Choi, Chang-Woo;Park, Young-Soo
    • Communications of the Korean Mathematical Society
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    • v.10 no.4
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    • pp.783-787
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    • 1995
  • In this paper we characterize cancellation ideals in terms of multiplication ideals. Especially, we find a condition for an ideal generated by three elements to be a cancellation ideal.

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Self-Interference Cancellation and Turbo Equalizer Design for the Single-band Full Duplex System using Single Antenna (단일 안테나를 사용하는 단일대역 전이중 통신을 위한 자기간섭신호제거와 터보 등화기 설계)

  • Choi, Jinkyu;An, Changyoung;Ryu, Heung-Gyoon
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.2
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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.

Design and Performance Evaluation of SSD (Simultaneous Single Band Duplex) System with HPA Nonlinearity (HPA 비선형 특성을 고려한 SSD(Simultaneous Single Band Duplex) 시스템의 설계와 성능 분석)

  • Keum, Hong-Sik;An, Changyoung;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.1
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    • pp.23-31
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    • 2015
  • In this paper, we design a SSD(simultaneous single band duplex) system using RF cancellation and digital cancellation. And then, we analyze performance of the SSD system using pre-distorter with HPA non-linearity. Also, we analyze digital cancellation performance of the SSD system using pre-distorter with HPA non-linearity. Additionally, digital cancellation cancels residual self-interference. In linear conditions, digital cancellation can cancel self-interference of 40dB. Therefore, the SSD system has good BER performance because most of self-interference is canceled. But, in HPA non-linearity conditions, digital cancellation cancels residual self-interference of 25dB. In this conditions, self-interference is greater than desired signal. Therefore, bit informations of distant station can not be received. But, we confirm that if the proposed system uses pre-distorter then bit information of distant station can be received by HPA non-linearity compensation. Also, we confirm that even though the proposed system uses pre-distorter, if HPA non-linearity increases then digital cancellation performance is degraded by imperfect compensation of HPA non-linerity.

A Study On the Feedforward Linear Power Amplifier Using Imperfect Signal Cancellation And Feedback (Imperfect Signal Cancellation과 Feedback을 이용한 Feedforward 선형전력증폭기에 관한 연구)

  • Park, Jung-Min;Yang, Seung-In
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.87-90
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    • 2003
  • In this paper, A feedforward linear power amplifier is analyzed for imperfect signal cancellation and negative feedback for basestaion of IMT2000 band. the distortion generatied by the error amplifier is reduced using an imperfect signal cancellation for a 1-carrier WCDMA source by 4.3dB at 2.5MHz offset and 6dB at 5MHz offset of IMSR(intermodulation signal power ratio) compared to a perfect signal cancellation system. additionally, An imperfect signal cancellation using negative feedback improved 1.3dB and 8.2dB at 2.5MHz and 5MHz offset of IMSR compared to an imperfect signal cancellation.

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A Study on the Bandwidth Efficient Self-Cancellation Scheme of Interchannel Interference (ICI) For OFDM Transmission Systems

  • Kim, Gi-Rae;Chung, Yeon-Do
    • Journal of information and communication convergence engineering
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    • v.4 no.4
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    • pp.162-165
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    • 2006
  • This paper presents a bandwidth efficient self-cancellation scheme for interchannel interference (ICI) in OFDM transmission systems. Conventional self-cancellation schemes provide an excellent cancellation capability of ICI for relatively low frequency offsets. However, this capability is achieved at the expense of bandwidth efficiency and thus a higher modulation level is often used to compensate for desired throughput. By applying a partial differential coding (PDC) to the transmit data prior to the ICI self-cancellation, bandwidth efficiency is greatly improved by a factor of 2, while maintaining a string of data (+1, -1) alternately for the ICI. self-cancellation in OFDM systems. Computer simulations show that the performance of the proposed scheme is comparable to the conventional self-cancellation scheme with slight performance degradation for relatively lower frequency offsets.

Nonlinear echo cancellation using FBEGS-PAP based Volterra filtering (FBEGS-PAP 알고리즘 기반 볼테라 필터링을 이용한 비선형 반향신호 제거)

  • Seo, Jae-Bum;Kim, Kyoung-Jae;Nam, Sang-Won
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.2
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    • pp.420-423
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    • 2007
  • In this paper, an efficient nonlinear echo cancellation method is proposed, whereby the fast block exact Gauss-Seidel pseudo affine projection (FBEGS-PAP) is further utilized for adaptive Volterra filtering. In particular, the proposed nonlinear echo cancellation approach requires lower computational complexity as in the conventional linear adaptive echo cancellation methods based on NLMS and GS-PAP, and still provides nonlinear echo cancellation performance similar to the GS-PAP method. Finally, echo cancellation performance of the proposed approach is demonstrated by providing some simulation results.

Multi user interference cancellation in satellite to ground uplink system Based on improved WPIC algorithm

  • Qingyang, Guan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.11
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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.