• Title/Summary/Keyword: PN code

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A Study on the PN code Acquisition for DS-CDMA System under Nakagami-m Fading (나카가미-m 페이딩을 고려한 DS-CDMA 시스템의 PN 부호 획득에 관한 연구)

  • 정남모;박진수
    • Journal of the Korea Society of Computer and Information
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    • v.6 no.3
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    • pp.78-83
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    • 2001
  • In this paper, we are considered Nakagami-m fading, which can model variable multipath mobile radio communication channel, in DS-CDMA system. System modeling using nakagami -m fading is suited for urban mobile communication channel with multipath. We used adaptive serial search PN code acquisition scheme and derived the detection probability($P_D$) and false alarm probability($P_FA$) which have influence on code acquisition time, over Nakagami-m fading. Detection probability($P_D$) and false alarm probability($P_FA$) are detection variable to decide PN code acquisition time and should use to calculate mean and variance. of acquisition time. From computer simulation, we analyzed mean and variance about PN code acquisition of fading channel. Then we can apply it to the H/W design of mobile communication.

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PN code acquisition for the N-path RAKE receiver in the DS/CDMA systems (DS/CDMA 이동통신 시스템의 N-경로 RAKE 수신기를 위한 PN 코드동기)

  • 이한섭;강창언
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.6
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    • pp.1510-1521
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    • 1996
  • This paper presents acquisition algorithm and an improved detection technique for the DS/CDMA (direction sequence code division multiple access) RAKE receiver in multipath fading channel. The DS/CDMA systems use the RAKE receiver, an accurate code acquisition is required for the RAKE branches. The algorithmis able to findthe pseudonoise (PN) code delay estimates for the RAKE branches in a multipath fading channel. In this paper a numerical method and computer simulation simulation have been developed for the acquisition system. The detection probability and mean acquisition time are investigated asa performance measure of the system using the Monte Carlo method. And also in order to analyze the effect of the acquisition on the RAKE receiver this paper bring out the effect of integration time, doppler frequency, processing gain and the number of users on the acquired code phase.

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PN Code Acquisition in a DS/CDMA Overlay Environment

  • Kim, Jin-Young
    • Proceedings of the IEEK Conference
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    • 2000.06a
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    • pp.185-188
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    • 2000
  • In this paper, performance of a PN code acquisition scheme is analyzed and simulated for a DS/CDMA overlay system where a CDMA user and a narrowband user coexist in the same frequency band. To suppress the NBI, an interference suppression filter is employed at the receiver front-end. From the simulation results, it is shown that the interference suppression filter is very effective for suppression of the NBI and rapid PN code acquisition in a DS/CDMA overlay environment. It is also shown that the one-sided tap number of 5 fur interference suppression filter is sufficient to suppress the NBI.

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Effect of Imperfect Power Control on Performance of a PN Code Tracking Loop for a DS/CDMA System

  • Kim, Jin-Young
    • Proceedings of the IEEK Conference
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    • 2000.06a
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    • pp.209-212
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    • 2000
  • In this paper, effect of imperfect power control on performance of a pseudonoise (PN) code tracking loop is analyzed and simulated for a direct-sequence/code-division multiple access (DS/CDMA) system. The multipath fading channel is modeled as a two-ray Rayleigh fading model. Power control error is modeled as a log-normally distributed random variable. The tracking performance of DLL (delay-locked-loop) is evaluated in terms of tracking jitter and mean-time-to-lose-lock (MTLL). From the simulation results, it is shown that the PN tracking performance is very sensitive to the power control error.

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Performance of PN Tracking with Extended Kalman Filter (Extended Kalman Filter기반의 PN부호 추적성능)

  • Bae, Jung-Nam;Koo, Sung-Wan;Kim, Sung-Ill;Kim, Jin-Young
    • 한국정보통신설비학회:학술대회논문집
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    • 2009.08a
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    • pp.112-114
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    • 2009
  • In this paper, a PN code tracking loop with extended Kalman filter (EKF) is proposed for a direct-sequence spread-spectrum. EKF is used to estimate amplitude and delay in a multipath fading channel. It is shown that tracking error performance is significantly improved by EKF compared with a conventional tracking loop.

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A Generalized Advanced Region Correlation (G-ARC) Scheme for BOC(pn,n) Modulated Code Tracking in GNSS (BOC(pn,n) 변조된 확산신호의 부호동기추적을 위한 일반화된 이른영역상관기법)

  • Yoo, Seung-Soo;Lee, Young-Yoon;Kim, Yeong-Moon;Yoon, Seok-Ho;Kim, Sun-Yong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.3C
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    • pp.329-340
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    • 2009
  • This paper proposes a novel code tracking scheme to track the fine code synchronization for BOC(pn,n) modulated spreading signals. The correlation function of BOC(pn,n) modulated spreading signals has been several peaks. In this paper, we observe that the correlation function in the advanced offset region remains almost unchanged, due to the multipath signals being received later than a line-of-sight signal. Based on this observation, we propose a novel code tracking scheme which is called the advanced region correlation (ARC) method for BOC(n,n) modulated spreading signals. And, we compare with the code tracking accuracy between the conventional and proposed methods in the static multipath and land mobile satellite system channels through the Monte-Carlo simulation. Then, base on the proposed scheme, we propose the generalized-ARC (ARC) scheme for BOC(pn, n) modulated spreading signals.

The Acquisition of the PN Code in the DS/CDMA System Considering Phase Error and Rake Receiver (위상 오류와 레이크 수신기를 고려한 DS/CDMA 시스템의 PN 부호 획득)

  • 김원섭;장문기;박진수
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.4
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    • pp.527-534
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    • 2002
  • In this paper, efficiency in the acquisition of the PN code of the DS/CDMA system was analyzed by using the Nakagami-m probability density function that can model diverse fading channels. The system considers the fading environment that inevitably exists in the mobile communications channel environment. To analyze the efficiency of the system, the equations related to detection probability PD and false alarm probability PFA required for the acquisition of the PN code were induced by using the Nakagami-m probability density function. They were verified through simulation. For the DS/CDMA system an adaptive serial search technique was applied to acquire the PN code. To correct phase error, the equations related to detection probability PD and false alarm probability PFA that influence the time to acquire codes were induced after adding the PLL to each branch of the Rake Receiver. By using an induced equation, detection probability PD and false alarm probability PFA were verified through simulation.

The Multi-user Interference Cancellation in CDMA System using SIMPLEX Code (Simplex 부호를 사용한 CDMA 시스템의 다원접속간섭제거)

  • 김남선
    • Journal of Korea Society of Industrial Information Systems
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    • v.6 no.1
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    • pp.15-23
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    • 2001
  • In this paper, we propose a system to cancel the multi-user interference of synchronous BPSK DS/CDMA systems. In this CDMA scheme, the spectrum of the user's signal is directly spread by means of the Simplex code or the phase offsetted PN code. But in arbitrary bit interval, we use the one spreading code of the Simplex code and the phase offsetted PN code. The receiver cancel the multi-user interference and demodulate information bits by using reference correlator. This paper presents a interference cancellation model and analyzes this system mathematically. The suggested system show that the interference resulting from other users are remarkably reduced. In AWGN and Nakagami fading environment we analyze interference generated from other users and compare the resulting performance with that of the conventional receiver in same user side.

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Wavelet-Based Watermarking using Threshold Values and PN-Code for Copyright Protection (저작권 보호를 위한 임계값과 PN-Code를 이용한 웨이블릿 영역에서의 워터마킹)

  • 정용훈;오휘빈;최영규;이준환;이상범
    • Journal of the Korea Computer Industry Society
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    • v.4 no.4
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    • pp.561-568
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    • 2003
  • This paper suggests that watermarking technique make use of Threshold Values and PN code for preservation of copyright. To protect copyright, six binary images that are generated by a Dynamic Threshold Value to LSB(least significant bit) of wavelet coefficient through wavelet conversion and watermark image use PN code to each frequency sphere-HL1, LH1, HL2, LH2, HL3, LH3, decide coordinates, operate XOR, and insert watermark. They put the sphere except from low frequency which has much image deterioration and high frequency which has weak loss compression in watermark. As an experimental result, we acquired watermark inserting image that has little image deterioration and extract watermark strongly.

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The characteristics of optical CDMA systems using PN codes and FBGs for ultra-fast optical access networks (초고속 광 가입자망 구축을 위한 PN 부호와 FBG를 이용한 광 CDMA의 특성분석)

  • 김봉규;연영희;김병휘;박상조
    • Korean Journal of Optics and Photonics
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    • v.13 no.6
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    • pp.501-505
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    • 2002
  • We have numerically analysed the effects of the light sourer spectral power distortion in an optical CDMA system using PN codes and FBGI for ultra-fast multi-access optical networks. The interference between two CDMA channels decreases with an increase in the code length and the .simultaneous access number is equal to the code length in the region of 0 to 15% spectral power distortion. As a result, the spectral power distortion with optical spectrum is very important in designing the optical CDMA systems.