• Title/Summary/Keyword: Multipath Channel

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Performance Analysis of PIC with Rake receiver in the Multipath Fading Channel (다경로 페이딩 채널에서 Rake 수신기를 사용하는 간섭제거 기법의 성능 분석)

  • 최태규;김태영;고균병;홍대식;강창언
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.153-156
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    • 2000
  • In this paper, the performance of the parallel interference cancellation(PIC) with RAKE receiver is more precisely analyzed in the uplink multipath fading channel. There is some difference between the proposed analysis method and the previous ones. Namely, it can be confirmed that the proposed analysis method by using stochastical characteristics is more accurate than the previous ones. It is also verified that the analysis result is similar to simulation as the number of user is increased. It is assumed that the channel estimation is perfect and the delay of multipath is Tc in the simulation.

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Multipath Channel Modeling for UWB (UWB 다중경로 전송환경 모델)

  • Bae Bag-Geun;Park Jin-Hwan;Ko Young-Eun;Choi Min-Sung;Bang Sung-Il
    • Proceedings of the IEEK Conference
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    • 2004.06a
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    • pp.23-26
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    • 2004
  • This paper analyzed time delay and phase distortion that generates in multipath and the degree of distortion due to power attenuation factor when UWB system is applied at indoor environment and the effects of indoor structure and material on distortion factors. Based on these distortion factors, channel model similar to actual environment is mathematically described and multipath and the degree of signal distortion generated when UWB system is applied to random environment is tested through channel model simulation and varies distortion factor that UWB system needs to consider in different indoor environment is analyzed.

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The Performance Simulation of OFDM System Employing Hierarchical 16QAM for Image and Data Transmission in Multipath Fading Channel

  • Kwak, Jae-Min;Ahn, Jun-Bae;Park, Ki-Sik;Cho, Sung-Eon;Cho, Sung-Joon
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2000.11a
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    • pp.12-15
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    • 2000
  • In this paper, we have evaluated the performance of an OFDM system using hierarchical 16QAM (OFDM/HL-16QAM) for achieving high quality and high speed data and image transmission in multipath fading channel. The wireless channel for performance evaluation is assumed to include AWGN and two ray multipath fading. Through simulation we have obtained the BER performance of the system according to $E_{b}$, $N_{0}$, then compared the received image quality of proposed system with that of conventional system. From the result, it is shown that the OFDM/HL-16QAM system is more effective for data and image transmission.n.n.

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The Analysis of Performance for OFDM over Mutipath Delay Spread Channel (다중경로 지연확산 채널상에서 OFDM에 대한 성능분석)

  • Won, Young-Jin
    • 전자공학회논문지 IE
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    • v.46 no.4
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    • pp.78-82
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    • 2009
  • We analyze an analysis of the performance of OFDM(Orthogonal Frequency Division Multiplexing) under multipath channel conditions, and to allow for different OFDM configurations. In this paper, the effects on multipath delay spread, peak power dipping, channel noise and time synchronization errors for the OFDM Signals are analyzed.

Intersymbol Decorrelating Detector for Asynchronous CDMA Systems

  • Zhang Gaonan;Bi Guoan;Kot Alex Chichung
    • Journal of Communications and Networks
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    • v.9 no.1
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    • pp.28-33
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    • 2007
  • Estimated channel information, especially multipath length and multipath channel of the desired user, is necessary for most previously reported linear blind multiuser detectors in code division multiple access (CDMA) systems. This paper presents a new blind intersymbol decorrelating detector in asynchronous CDMA systems, which uses the cross correlation matrix of the consecutive symbols. The proposed detector is attractive for its simplicity because no channel estimation is required except the synchronization of the desired user. Compared with other reported multiuser detectors, simulation results show that the proposed detector provides a good performance when the active users have significant intersymbol interference and the multipath length is short.

A New Diversity Combining Scheme Based on Interleaving Method for Time-of-arrival Estimation of Chirp Signal

  • Jang, Seong-Hyun;Chong, Jong-Wha
    • Journal of IKEEE
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    • v.16 no.2
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    • pp.153-158
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    • 2012
  • A new diversity combining scheme is proposed for time-of-arrival (TOA) estimation of chirp signal in dense multipath channel. In the multipath channel, the performance of TOA estimation using conventional correlation matrix-based diversity combining scheme is degraded due to the lack of de-correlation effect. To increase the de-correlation effect, the proposed diversity scheme employs interleaving method based on the property of de-chirped signal. As a result, the proposed scheme increases de-correlation effect and also reduces the noise of TOA estimation. Finally, the diversity achieved from the proposed scheme improves TOA estimation performance. The de-correlation effect is analyzed mathematically. The estimation accuracy of the proposed diversity scheme is superior to that of conventional diversity scheme in multipath channel.

Performance of an Orthogonal Multicarrier CDMA System over Rayleigh/Rician Fading Channels

  • 유창완;윤원식
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.7
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    • pp.1033-1043
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    • 1999
  • We consider an improved multicarrier(MC) CDMA system that combines both DS-CDMA with a concatenated orthogonal/PN spreading sequence and MC modulation. This system incorporates the advantages of DS-CDMA with a concatenated sequence to achieve large user capacity and MC modulation technique to combat the effects of a multipath fading channel and intersymbol interference(ISI). Considering voice activity and imperfect sectorization, the system performance is analysed for the maximal ratio combiner(MRC) under a multicell, multiuser, and multipath Rayleigh/Rician fading channels. The performance of the system is improved much more for the single path fading channel compared to the multipath fading channel. Also the system is shown to have the more improved average bit error rate(BER) over the orthogonal MC-CDMA with the conventional PN sequence.

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Performance of Denoising Autoencoder for Enhancing Image in Shallow Water Acoustic Communication (천해 음향 통신에서 이미지 향상을 위한 디노이징 오토인코더의 성능 평가)

  • Jeong, Hyun-Soo;Lee, Chae-Hui;Park, Ji-Hyun;Park, Kyu-Chil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.2
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    • pp.327-329
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    • 2021
  • Underwater acoustic communication channel is influenced by environmental parameters such as multipath, background noise and scattering. Therefore, a transmitted signal is influenced by the sea surface and the sea bottom boundaries, and a received signal shows a delay spread. These factors create a noise in the image and degrade the quality of underwater acoustic communication. To solve these problems, in this paper, we evaluate the performance of an underwater acoustic communication model using a denoising auto-encoder used for unsupervised learning. Noise images generated by the underwater multipath channel were collected and used as training data. Experimental results were analyzed as a PSNR parameter that expressed the noise ratio of the two images.

Analysis of W-CDMA System with Smart Antenna for Angular Spread in Realistic Wideband Multipath Channel (광대역 다중경로 실측 채널에서 스마트 안테나를 적용한 광대역 CDMA 시스템의 각도퍼짐에 따른 성능분석)

  • 전준수;김철성
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.5
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    • pp.527-535
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    • 2003
  • In this paper, the performance of W-CDMA system with smart antenna is analyzed for angular spread in realistic wideband multipath channel. The realistic wideband channel is assumed, one of which is JTC channel model. And each multipath is assumed as a reflective wave from only one direction (only one cluster) in space. Several multipaths within one chip are distinguished into each one and the strongest signal is selected. As a result, the performance of the W-CDMA system with smart antenna in realistic wideband multipath channel has been considerably improved in proportion to the increase of angular spread.

The Performance Comparison Of FSK, BPSK, DPSK In Underwater Communication Channel (수중통신채널에서 FSK, BPSK, DPSK의 성능비교)

  • 박지현;백승관;노용주;윤종락
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2001.05a
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    • pp.359-362
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    • 2001
  • Analog communication systems using AM, FM modem have been developed. Digital communication systems using digital modems, which is by expansion of digital hardware skill have been recently developed. In order to accomplish a reliable communication it is important to overcome ocean environmental channel characteristics such as transmission loss, ambient noise and multipath effect etc. Specially, the effect of multipath is the most important element that determines the performance of underwater communication system in shallow water. Multipath channel can be divided a vertical and horizontal channel. the former is defined the channel to have large path-delay times between a direct wave and reflected waves. The latter shows relatively small path-delay times between a direct and reflected waves in compared with a vertical channel. In this paper, The performance of FSK, PSK and DPSK modem with respect to the vertical and horizontal multipath communication channels it described and compared.

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