OFDM receivers using oversampling with rational sampling ratios

Lee, Young-Su; Seo, Bo-Seok

doi:10.1109/tce.2009.5373729

Cited by 13 publications

(7 citation statements)

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“…The use of oversampling to improve the SNR in OFDM transmission has been proposed in the literature [40,41]. Random receiver noise is reduced by oversampling based on the assumption that the signal is coherent and that the noise is random.…”

Section: Measurement Results and Analysismentioning

confidence: 99%

Experimental evaluation of theperformance of 2×2 MIMO-OFDM for vehicle-to-infrastructure communications

Onubogu

Ziri-Castro

Jayalath

et al. 2015

J Wireless Com Network

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In this paper, a novel 2 × 2 multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) testbed based on an Analog Devices AD9361 highly integrated radio frequency (RF) agile transceiver was specifically implemented for the purpose of estimating and analyzing MIMO-OFDM channel capacity in vehicle-to-infrastructure (V2I) environments using the 920 MHz industrial, scientific, and medical (ISM) band. We implemented two-dimensional discrete cosine transform-based filtering to reduce the channel estimation errors and show its effectiveness on our measurement results. We have also analyzed the effects of channel estimation error on the MIMO channel capacity by simulation. Three different scenarios of subcarrier spacing were investigated which correspond to IEEE 802.11p, Long-Term Evolution (LTE), and Digital Video Broadcasting Terrestrial (DVB-T)(2k) standards. An extensive MIMO-OFDM V2I channel measurement campaign was performed in a suburban environment. Analysis of the measured MIMO channel capacity results as a function of the transmitter-to-receiver (TX-RX) separation distance up to 250 m shows that the variance of the MIMO channel capacity is larger for the near-range line-of-sight (LOS) scenarios than for the long-range non-LOS cases, using a fixed receiver signal-to-noise ratio (SNR) criterion. We observed that the largest capacity values were achieved at LOS propagation despite the common assumption of a degenerated MIMO channel in LOS. We consider that this is due to the large angular spacing between MIMO subchannels which occurs when the receiver vehicle rooftop antennas pass by the fixed transmitter antennas at close range, causing MIMO subchannels to be orthogonal. In addition, analysis on the effects of different subcarrier spacings on MIMO-OFDM channel capacity showed negligible differences in mean channel capacity for the subcarrier spacing range investigated. Measured channels described in this paper are available on request. Keywords: MIMO-OFDM; Capacity; V2I; LOS; Channel Review IntroductionMultiple-input multiple-output (MIMO) systems have attracted considerable attention due to the increasing requirements of high capacity, spectral efficiency, and reliability in wireless communications. For example, MIMO systems have been adopted in the Long-Term Evolution (LTE) system, and it is expected that the upcoming developments in IEEE 802.11p and Digital Video Broadcasting Terrestrial (DVB-T) wireless standards will include the use of MIMO. It has been shown [1] that MIMO, *Correspondence: okechukwu.onubogu@qut.edu.au 1 School of Electrical Engineering and Computer Science, Queensland University of Technology, Brisbane, QLD 4001, Australia Full list of author information is available at the end of the article when deployed in a rich scattering environment, is capable of achieving high spectral efficiency, capacity, and reliability by exploiting the increased spatial degrees of freedom. MIMO is often combined with the orthogonal frequency division multiplexing (OFDM) in m...

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Section: Measurement Results and Analysismentioning

confidence: 99%

Experimental evaluation of theperformance of 2×2 MIMO-OFDM for vehicle-to-infrastructure communications

Onubogu

Ziri-Castro

Jayalath

et al. 2015

J Wireless Com Network

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“…The means of the components W, X, Y, Z are given in Equations (43), (44), (45), and (46) at the top of this page, respectively. Also, the second moments of W, X, Y, Z are given in Equations (47), (48), (49), and (50), respectively.…”

Section: Appendix a Statistical Means And Second Moments Of The Compomentioning

confidence: 99%

“…With the scenario of communication in small areas with low rate, the root-mean-square (RMS) delay spread is less than a chip duration, hence the wireless transmission environment can be considered as a flat fading channel [42]. The application of oversampling technique to improve communication features at the receiving side has been studied in [43][44][45]. In our scenario, oversampling is used to exploit the flat fading characteristic of the channel in order to increase the signal-to-noise (SNR) at the output of the correlator, aiming to improve the bit-error-rate (BER) performance of the system.…”

Section: Introductionmentioning

confidence: 99%

An Oversampling-based Correlator-type Receiver for DCSK Communication Systems Over Generalized Flat Rayleigh Fading Channels

Nguyen

2016

REV-JEC

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Abstract-This paper proposes an oversampling-based correlator-type receiver for Differential Chaos-shift Keying (DCSK) communication systems, which can exploit the flat-fading characteristic of multipath channels in order to improve the system performance. At the receiver, the incoming signal is sampled with a sampling rate higher than chip rate before feeding to a correlator. This oversampling step aims to specifically determine delayed-signal components from fading multipath channels, which can be combined together by the correlator in order to increase the ratio of signal-to-noise at its output. In particular, the performance of the proposed receiver is investigated by means of a generalized flat Rayleigh fading channel which has one primary path (i.e., the path having the shortest transmission period) and multiple secondary paths (i.e., the other remaining paths with delays). Mathematical models in discrete-time domain for the conventional transmitter, generalized channel, and proposed receiver are proposed and analyzed. The theoretical bit-error-rate (BER) expression is first derived and then distribution histogram for the ratio of variable bit energy to noise power spectral density is computed. The BER performance is finally estimated by integrating the BER expression over all possible values of the histogram. Numerical simulations with specific parameters are carried out and then simulated performances are shown in comparison to estimated ones. Obtained results point out that the system performance is significantly improved when the number of secondary paths increases.

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“…This oversampling step aims to specifically determine the delayed-signal components from fading multipath channels, which can be combined together by the correlator in order to increase the signal-to-noise ratio at its output. The application of an oversampling step at the receiver side has been shown to improve the communication features in [28]- [30].…”

Section: Introductionmentioning

confidence: 99%

Performance of Direct-Oversampling Correlator-Type Receivers in Chaos-Based DS-CDMA Systems Over Frequency Non-selective Fading Channels

Quyen

Barlet‐Ros²

2017

Wireless Pers Commun

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In this paper, we present a study on the performance of directoversampling correlator-type receivers in chaos-based Direct-sequence code division multiple access (DS-CDMA) systems over frequency non-selective fading channels. At the input, the received signal is sampled at a sampling rate higher than the chip rate. This oversampling step is used to precisely determine the delayed-signal components from multipath fading channels, which can be combined together by a correlator for the sake of increasing the SNR at its output. The main advantage of using direct-oversampling correlator-type receivers is not only their low energy consumption due to their simple structure, but also their ability to exploit the non-selective fading characteristic of multipath channels to improve the overall system performance in scenarios with limited data speeds and low energy requirements, such as Low-rate wireless personal area networks (LR-WPAN). Mathematical models in discrete-time domain for the conventional transmitting side with multiple access operation, the generalized non-selective Rayleigh fading channel, and the proposed receiver are provided and described. A rough theoretical bit-error-rate (BER) expression is first derived by means of Gaussian approximation. We then define the main component in the expression and build its probability mass function (PMF) through numerical computation. The final BER estimation is carried out by integrating the rough expression over possible discrete values of the PFM. In order to validate our findings, PC simulation is performed and simulated performance is compared with the corresponding estimated one. Obtained results

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OFDM receivers using oversampling with rational sampling ratios

Cited by 13 publications

References 10 publications

Experimental evaluation of theperformance of 2×2 MIMO-OFDM for vehicle-to-infrastructure communications

Experimental evaluation of theperformance of 2×2 MIMO-OFDM for vehicle-to-infrastructure communications

An Oversampling-based Correlator-type Receiver for DCSK Communication Systems Over Generalized Flat Rayleigh Fading Channels

Performance of Direct-Oversampling Correlator-Type Receivers in Chaos-Based DS-CDMA Systems Over Frequency Non-selective Fading Channels

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