• Title/Summary/Keyword: Rake receivers

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Performance Analysis of RAKE Receivers for IR-UWB Systems in Indoor Multipath Radio Channel (실내 다중경로 무선채널의 IR-UWB 시스템에서 레이크 수신기의 성능 분석)

  • Kim, Eun-Cheol;Yoon, Byung-Wan;Yang, Jae-Soo;Kim, Jin-Young
    • 한국정보통신설비학회:학술대회논문집
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    • 2008.08a
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    • pp.253-256
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    • 2008
  • In this paper, we analyze the performance of RAKE receiver for impulse radio-ultra wide band (IR-UWB) systems in indoor multipath radio channel. Pulse position modulation-time hopping (PPM-TH) signal is considered. And we also consider three types of RAKE receivers, which are ideal RAKE, selective RAKE, and partial RAKE receivers. The indoor channel is modeled as the modified Saleh and Valenzuela (SV) model which has been proposed as a UWB channel model by the IEEE group, IEEE 802.15.SG3a.

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Space Time Rake Receivers for Time Division Synchronous CDMA Base Stations

  • Xiao Yang;Lee Kwang-Jae;Lee Moon-Ho;Cho Sam-Goo
    • Journal of electromagnetic engineering and science
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    • v.6 no.2
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    • pp.83-91
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    • 2006
  • In this paper, we develop space-time(ST) Rake receivers for Time Division Synchronous Code Division Multiple Access(TD-SCDMA) base stations(BS). The beamforming of BS transforms the uplink MIMO channel space into many sub-sectors' channels to be nearly orthogonal, thus, well established 1-D Rake technology can be used to TD-SCDMA base station to construct ST Rake, which simplified the system's implementation as well as enlarged users' capacity by the beamforming. The construction and capacity of MIMO sub-sectors by multi-beamforming have been presented. The proposed ST Rake algorithm include the multi-beamforming algorithm for MIMO sub-sectors and classical 1-D Rake algorithm. The calculating formulas for interference plus noise ratio(SINR) and bit error rate(BER) have been derived. Simulations verify that the proposed ST Rake receiver for BS is effective, and the BS systems can get higher system capacity and can be of better performance than presented TD-SCDMA systems.

Performance of Optimum and Suboptimum Rake Receivers in the Presence of Impulsive Noise (충격성 잡음에서 최적 갈퀴수신기와 준최적 갈퀴수신기의 성능)

  • Kim, Byoung-Soo;Choi, Sang-Won;Kwon, Hyoung-Moon;Bae, Jin-Soo;Song, Iick-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.9C
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    • pp.899-906
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    • 2005
  • In this paper, the optimum maximum-likelihood rake receiver for impulsive, fading channel is derived, and a sub-optimun rake receiver with reduced complexity is obtained for practical purposes. Numerical results show that, when the noise is impulsive, the rake receivers designed for impulsive noise offer performance improvement over those optimized for Gaussian environment. It is also observed that, as the number of fingers increases, the performance of the rake receivers designed for impulsive environment improves while the rake receiver optimized for Gaussian environment experiences performance degradation in impulsive environment.

Performance of Rake Receiver for Pulse Position Modulation-Time Hopping Ultra Wide Band Systems in Indoor Environments (실내 환경의 펄스 위치 변조-시간 도약 초광대역 무선통신 시스템에서 레이크 수신기 성능)

  • Kim, Joo-Chan;Kim, Jin-Young
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.3
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    • pp.179-184
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    • 2010
  • In this paper, we analyze and simulate the performance of RAKE receiver for ultra wide band (UWB) systems in indoor multipath radio channel. Pulse position modulation-time hopping (PPM-TH) signal is considered. And we also consider three types of RAKE receivers, which are ideal RAKE, selective RAKE, and partial RAKE receivers. The indoor channel is modeled as the modified Saleh and Valenzuela (SV) model which has been proposed as a UWB channel model by the IEEE group, IEEE 802.15.SG3a.

A Hypothesis Test Approach to Template Selection for UWB Rake Receivers (가설검증 방식을 통한 UWB Rake 수신기의 기준신호 선택 기법)

  • Lee Joon-Yong;Yoo Sungyul;Yoon Sung-Jun;Ha Dong-Heon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.2C
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    • pp.109-116
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    • 2006
  • Many application scenarios of ultra-wideband(UWB) radio assume non-line-of-sigit(non-LoS) signal propagations. Through-material propagation of UWB signal introduces a distortion of the waveform as well as attenuation, which will introduce a decrease of the correlation coefficient between the correlator template and the received signal. A hypothesis test approach to selection of the template waveform for UWB rake receivers is posed. Linde-Buzo-Gray(LBG) algorithm is used to select the candidate waveforms which are used to setup the hypothesis test. The performance of the algorithm is tested using a set of indoor non-LoS propagation measurement data.

Performance of Selective Rake Receivers for Weak Signals in Impulsive Fading Channels

  • Kang, Hyun-Gu;Choi, Seung-Won;Oh, Jong-Ho;Song, Iick-Ho
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.209-212
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    • 2005
  • In this paper, based on a detection criterion proposed recently, we investigate the performance of selective rake receivers (SRRs) in fading environment exhibiting impulsive nature. Optimum and suboptimum SRRs for the impulsive fading channel are derived, and suboptimum SRRs with reduced complexity are obtained for practical purposes. Simulation results confirm that, when the noise is impulsive the SRRs designed for impulsive noise offer performance improvement over those optimized for Gaussian environment. The suboptimum SRR is observed to exhibit almost the same performance as the optimum SRR.

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Performance of Multiple Order Selection Combining RAKE receiver in Multi-bandwidth CDMA System (다중 대역 확산 CDMA 시스템에서의 다중 선택 결합 RAKE 수신기의 성능 분석)

  • 권순일;홍인기
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.5A
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    • pp.593-601
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    • 2000
  • In a multi-bandwidth CDMA system, the performance of multiple order selection combining rake receivers are analyzed according to the spreading bandwidth of the system and the delay spread of the Rayleigh fading channel. The results for various channel environments indicate a tradeoff between total received signal energy and multipath fading immunity. Increasing the occupied bandwidth of the system(wide-bandwidth spreading) gives better performance for small delay spread environments, while gathering more energy(narrow-bandwidth spreading)gives better performance for large delay spread environments. It is shown that the performance difference between low and high order selection combining grows larger as the spreading bandwidth increases. It is also noted that performance degrades by increasing the bandwidth above a certain point and the optimum spreading bandwidth for each channel environment decreases as the delay spread of the channel increases.

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On the Performance of Multi-User 2PPM-TH-UWB SIMO Systems in Multipath Channels

  • Baek, Sun-Young;Kang, Yun-Jeong;Kim, Sang-Choon
    • Journal of information and communication convergence engineering
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    • v.7 no.3
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    • pp.286-291
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    • 2009
  • In this paper, the performance of ultra-wideband (UWB) single input multiple output (SIMO) systems to achieve high data rate communications is studied in dense multipath environments. The effects of spatial and temporal diversities on the performance of multi-user time-hopping UWB systems using binary pulse position modulation (2PPM) are analyzed. The reduced-complexity Rake receivers based on the selective combining (called SRake) and partial combining (called PRake) are considered. The theoretical and simulation results show that the BER performance of the UWB system can be enhanced as the number of array elements and/or Rake fingers increases. Moreover, we observe that SRake is more effective for the IR-UWB systems to achieve a good BER performance, as compared with PRake.

Optimum Rake Processing for Multipath Fading in Direct-Sequence Spread-Spectrum Communication Systems (주파수대역 직접확산 통신시스템에서 다중경로 페이딩 보상을 위한 최적 레이크 신호처리에 관한 연구)

  • 장원석;이재천
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.10C
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    • pp.995-1006
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    • 2003
  • It is well know that in the wireless communication systems the transmitted signals can suffer from multipath fading due to the wave propagation characteristics and the obstacles over the paths, resulting in serious reduction in the power of the received signals. However, it is possible to take advantage of the inherent diversity imposed in the multipath reception if the underlying channel can be properly estimated. One of the diversity reception methods in this case is Rake processing. In this paper we study the Rake receivers for the direct-sequence spread-spectrum communication systems utilizing PN (pseudo noise) sequences to achieve spread spectrum. A conventional Rake receiver can use the finite-duration impulse (FIR) filter followed by the PN sequence demodulator, where the FIR filter coefficients are the reverse-ordered complex conjugate values of the fading channel impulse response estimates. Here, we propose a new Rake processing method by replacing the aforementioned PN code sequence with a new set of optimum demodulator coefficients. More specifically, the concept of the new optimum Rake processing is first introduced and then the optimum demodulator coefficients are theoretically derived. The performance obtained using the new optimum Rake processing is also calculated. The analytical results are verified by computer simulation. As a result, it is shown that the new optimum Rake processing method improves the MSE performance more than 10 dB over the conventional one using the fixed PN sequence demodulator. It is also shown that the new optimum Rake processing method improves the MSE performance about 10 dB over the Adaptive Correlator that performs the combining of the multipath components and PN demodulation concurrently. And finally, the MSE performance of the optimum Rake demodulator is very close to the MSE performance of OPSK demodulator under the AWGN channel.

Analysis of CI/DS-CDMA Communication Systems using Interference of Multiple Carriers (다중반송파간섭을 이용한 CI/DS-CDMA 통신시스템 특성분석)

  • 이강봉;이정재
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2001.05a
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    • pp.129-132
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    • 2001
  • In this paper a new multiple access scheme, CI/DS-CDMA rising the interference of multiple carriers, is introduced. In this system the chip is made up of N orthogonal carriers equally spaced in frequency, where N corresponds to the number of chips in DS-CDMA. The characteristics of CI/DS-CDMA systems in a typical frequency selective fading channel environment, are analyzed. And it is shown that the frequency diversity benefits of this system result in significant performance enhancements relative to traditional DS-CDMA with RAKE receivers.

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