• Title/Summary/Keyword: 다중접속간섭

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Performance Improvement of TH PPM UWB-IR System with CCI Canceller in Multi-User Interference Environment (다중 사용자 간섭 환경에서 CCI Canceller를 채용한 TH PPM UWB-IR 시스템의 성능 개선)

  • Lee Yang-Sun;Kang Heau-Jo
    • Journal of Digital Contents Society
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    • v.5 no.3
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    • pp.171-175
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    • 2004
  • In this paper, We applied CCI canceller to remove multi-user interference in co-channel environment and improved performance of TH PPM UWB-IR system. As a result, We could get reception performance that data transmission of high speed is available in small reception power applying CCI canceller. Also, We could get permission available channel capacity to maximum access number 40 in high speed transmission environment more than 100Mbps.

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Performance Analysis of BPSK Multitone DS/CDMA System with Interference Canceller (간섭 제거기를 사용한 BPSK 다중 톤 DS/CDMA 시스템의 성능 분석)

  • 박승근;강병권
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.2 no.4
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    • pp.519-529
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    • 1998
  • In this paper, we analyze the effects of interference canceller on the performance of multitone DS/CDMA system. Although there are various kinds of interference cancellers suggested by different researchers, we adopt a canceller used by Yoon et at.[9]. We consider three kinds of inteferences, that is, multiPath interference(MPI), interchannel interference(ICI) and multiple access interference(MPI). The equations for variances ate derived for the inteferences and thermal noise used for signal to noise ratio calculation. We also consider RAKE reception over multipath channel and three stage interference canceller used for performance improvement. We draw some conclusions that interference canceller is effective in multitone DS/CDMA system and the performance is further improved with the higer order of diversity and larger number of PN chips.

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The multi-use interfernce cancellation of synchronous DS/CDMA system using SIMPLEX coed and PN code (SIMPLEX 부호와 PN 부호를 사용한 동기 DS/CDMA 시스템의 다원접속간섭제거)

  • 김남선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.4
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    • pp.967-975
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    • 1998
  • This paper presents a system to cancel the multi-user interference of synchronous DS/CDMA systems by using the estimation circuit and the reference correlator. In the code-division multiple access(CDMA) scheme, the spectrum of the user's signal is directly spreaded by means of the Simplex coed or the phase offsetted PN code. It is interesting for the Simplex code and the PN code to have a similar correalation property. It these codes are used in DS/CDMA systems, the number of acceptable users can be increased in comparison with conventioal DS/CDMA systems. This thesis presents a interference cancellation model to cancel the multi-use interference in DS/CDMA systems by using Simples code of PN code as a spreading sequence. In AWGN environment, we analyze interference generated from other users and compare the resulting performance with that of the conventioanl receiver in same user side.

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Improvement of Performance in the DS-CDMA / DPSK Cellular Mobile Communication System using CCI Canceller and MRC Diversity (DS-CDMA/DPSK 셀룰라 이동통신 시스템에서 간섭 제거기와 최대비 합성 다이버시티에 의한 성능의 개선)

  • 우병훈;오창헌;조성준
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.5 no.1
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    • pp.22-30
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    • 1994
  • The error probability of the DS-CDMA / DPSK cellular mobile communication system with CCI canceller and MRC diversity reception technique has been analyzed in the cellular radio channel which is characterized by AWGN, Multi-User Interference(MUI) and m-distribution fading. System capacity i. e., number of user per cell has been derived and the evaluated results are shown in figures as a function of PN code sequence length, fading index, BER, number of diversity branches and $E_b/N_o$, Here, the voice activity factor is assumed to be 3/8, the number of sectors in a cell 3 and Multi-User Iner- ference is modeled as Gaussian process.

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Performance Analysis of Multi-Carrier DS-CDMA System in Multipath Rician Fading Channel (다중경로 라이시안 페이딩 채널에서 Multi-Carrier DS-CDMA 시스템의 성능 해석)

  • 김영철;노재성;오창헌;조성준
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.3
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    • pp.378-390
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    • 2001
  • In this paper, it is analyzed that the error performance of a Multi-Carrier DS-CDMA system in a single cell with multipath Rician fading and multiple access interference (MAI) and the error performance of the system is compared with that of a Sing1e-Carrier DS-CDMA system. Moreover, the convolutional coding techniques with code rate of 1/2, 1/3, and 1/4 are adopted in order to improve the error performance degraded by the multipath fading and MAI and performance improvement through the coding techniques is analyzed. As a result, it is shown that the number of users in each system can be determined by the number of branches of the rake receiver in a Single-Carrier DS-CDMA system and the number of carriers in a Multi-Carrier DS-CDMA system. Furthermore, the convolutional coding should be chosen with considering the trade-off between coding gain and a power limitation in a Multi-Carrier DS-CDMA system. In case of increasing the number of carriers, the processing gain is decreased but the error performance is improved through the effect of frequency diversity and the system can be possibility implemented due to the low chip rate.

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On Frequency Separation among Radio Access Technologies in Heterogeneous Networks (이기종 네트워크를 구성하는 무선접속 기술간 주파수 이격 분석)

  • Lee, Kyoung-Jae;Jo, Han-Shin
    • Journal of Internet Computing and Services
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    • v.16 no.6
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    • pp.1-9
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    • 2015
  • In this paper, we study the coexistence of typical radio access technologies (WiMAX, CDMA, WLAN) in heterogeneous networks. Although the radio accesses employ different frequency band, they can interfere with each other due to out-of- band emission. We compute the minimum adjacent channel interference ratio (ACIR) to satisfy the allowable level of interference, and the resulting minimum frequency separation (guard band) between interfering and victim system. We observe that WiMAX-WLAN coexistence and WiMAX-CDMA coexistence are feasible with at least 20 MHz and 15 MHz guard bands, respectively.

Performance Analysis of MC-DS-CDMA System Using a Interference Suppression Method in a Multipath Fading Channel (다중 경로 페이딩 채널 환경에서 다중반송파 DS-CDMA 시스템의 간섭 제거 성능 분석)

  • Park Tae-Yoon;Choi Jae-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.8B
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    • pp.745-751
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    • 2002
  • The performance of existing CDMA-type multiple access data transmission systems is limited by interferences due to adverse mobile communication channel characteristics. Among them, the multi-user interference becomes one of the major performance degradation factors because the signal-to-signal orthogonality can be easily perturbed when numerous user signals are distorted by multipath fading channels and mixed together. In order to enhance the performance of CDMA-type systems by suppressing the multi-user interference, we have adopted chip-based cyclic prefix insertion along with adaptive one-tap DFE equalization into MC-DS-CDMA, which is known for its robustness in the frequency selective multipath fading channel environment. In order to assess the performance of the proposed system, a set of computer simulations is performed in the reverse link in which each user signal undergoes different multipath Rayleigh fading. The results show us a superior performance of our system over other CDMA systems in terms of SNR to BER measurements.

On Improved Outage Probability of Correlated Superposition Coding/non-SIC NOMA (상관 관계 중첩 코딩/non-SIC 비직교 다중접속의 향상된 Outage 확률에 관해)

  • Chung, Kyu-Hyuk
    • The Journal of the Korea institute of electronic communication sciences
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    • v.16 no.4
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    • pp.611-616
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    • 2021
  • This paper investigates the improved outage probability of correlated superposition coding(CSC)/non-successive interference cancellation(SIC) non-orthogonal multiple access(NOMA) scheme. For this, first, we calculate the outage probability of the conventional independent superposition coding(ISC)/SIC NOMA scheme. Then, simulations demonstrate that the outage probability of CSC/non-SIC NOMA improves greatly, with respect to that of conventional ISC/SIC NOMA. As a result, CSC/non-SIC NOMA schemes could be a promising technique in 5G networks, especially with such improved outage probability.

A Study on the Efficient Transmission of UWB System in Imperfect Channel Environment (불완전 채널 환경에서 초광대역 전송 시스템의 효율적인 전송에 관한 연구)

  • Lee, Yang-Sun;Kang, Heau-Jo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.1
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    • pp.233-236
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    • 2005
  • 본 논문에서는 중첩되는 두 개 이상의 PAN의 무선영역이 간섭을 일으키는 경우와 다수의 무선기기가 동시에 접속하는 경우에 대비하여 간섭마진 정보를 이용한 가변 전송율을 갖는 UWB 통신 시스템을 제안한다. 또한, 가변 전송율 UWB 통신 시스템을 불완전 다중접속 간섭 환경에서 고정 전송율을 갖는 UWB 통신 시스템과의 성능을 비교 분석하고 전송효율을 평가하였다.

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Performance Analysis of DS/CDMA Communication System with MRC Diversity and CCI Canceller in Nakagami Fading Environment (나카가미 페이딩 환경하에서 MRC 다이버시티와 간섭제거기를 채용한 DS/CDMA 통신 시스템의 성능 분석)

  • 소준영;강희조
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.7
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    • pp.1010-1021
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    • 1999
  • In this paper, error performance of DS/CDMA GMSK system has been analyzed in a radio channel which is characterized by multi-user interference(MUI) and Nakagami fading. The DS/CDMA GMSK system adopts Maximum Ratio Combining(MRC) diversity and co-channel interference (CCI) to enhance system performance. Using the derived error probability equation, the error performance of DS/CDMA GMSK system has been evaluated and shown in figures to discuss as a function of PN code length(N), number of multi-user(K), number of diversity branch(L), and bit energy per noise power ratio ($E_b/N_0$), fading index(m). The results show that there is a substantial enhancement in performance by employing an MRC diversity or a CCI canceller. Additional improvement can be obtained when the MRC diversity and the CCI canceller are adopted in cascade form. Consequently, we expected that proposed system structure is reliable to the voice communication system in Nakagami fading, multi-user interferences and multipath channel.

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