Pilot Spacing in Orthogonal Frequency Division Multiplexing Systems on Practical Channels

Rinne,; Renfors,

doi:10.1109/icce.1996.517185

Cited by 16 publications

(14 citation statements)

References 7 publications

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“…The respective number of subcarriers used in the experiment is K = 512, 1024, and 2048. The subcarrier spacing is ∆f = 23.44 Hz, 11.72 Hz, and 5.86 Hz, and the OFDM block duration is T = 1/∆f = 42.67 ms, 85.33 ms, and 170.67 ms. We use rate 2/3 convolutional coding, obtained by puncturing a rate 1/2 code with the generator polynomial (23,35). Coding is applied within the data stream for each OFDM block.…”

Section: Performance Results For the Experiments In Buzzards Baymentioning

confidence: 99%

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Multicarrier Communication Over Underwater Acoustic Channels With Nonuniform Doppler Shifts

Zhou

Stojanovic

et al. 2008

IEEE J. Oceanic Eng.

712

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Abstract-Underwater acoustic (UWA) channels are wideband in nature due to the small ratio of the carrier frequency to the signal bandwidth, which introduces frequency-dependent Doppler shifts. In this paper, we treat the channel as having a common Doppler scaling factor on all propagation paths, and propose a two-step approach to mitigating the Doppler effect: (1) non-uniform Doppler compensation via resampling that converts a "wideband" problem into a "narrowband" problem; and (2) high-resolution uniform compensation of the residual Doppler. We focus on zero-padded OFDM to minimize the transmission power. Null subcarriers are used to facilitate Doppler compensation, and pilot subcarriers are used for channel estimation. The receiver is based on block-by-block processing, and does not rely on channel dependence across OFDM blocks; thus, it is suitable for fast-varying UWA channels. The data from two shallow water experiments near Woods Hole, MA, are used to demonstrate the receiver performance. Excellent performance results are obtained even when the transmitter and the receiver are moving at a relative speed of up to 10 knots, at which the Doppler shifts are greater than the OFDM subcarrier spacing. These results suggest that OFDM is a viable option for high-rate communications over wideband underwater acoustic channels with nonuniform Doppler shifts.

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Section: Performance Results For the Experiments In Buzzards Baymentioning

confidence: 99%

“…Since the pilots are equi-spaced, we have that [23], and since they are of unit-amplitude, we have that D H s D s = I Kp . Therefore, the LS solution for (18) simplifies toĥ…”

Section: ) Cfo Estimationmentioning

confidence: 99%

Multicarrier Communication Over Underwater Acoustic Channels With Nonuniform Doppler Shifts

Zhou

Stojanovic

et al. 2008

IEEE J. Oceanic Eng.

712

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“…A cyclic prefix (CP) and pilot tones for channel estimation [2]- [6] constitute a significant overhead or bandwidth loss, motivating the development of blind techniques for OFDM. They use statistical or deterministic properties of the transmit and receive signals; properties such as CP and pilot-induced redundancy, cyclostationarity, finite alphabets, and virtual carriers have been exploited [7]- [13].…”

Section: Introductionmentioning

confidence: 99%

Joint data detection and channel estimation for OFDM systems

Cui

Tellambura

2006

IEEE Trans. Commun.

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Abstract-We develop new blind and semi-blind data detectors and channel estimators for orthogonal frequency-division multiplexing (OFDM) systems. Our data detectors require minimizing a complex, integer quadratic form in the data vector. The semi-blind detector uses both channel correlation and noise variance. The quadratic for the blind detector suffers from rank deficiency; for this, we give a low-complexity solution. Avoiding a computationally prohibitive exhaustive search, we solve our data detectors using sphere decoding (SD) and V-BLAST and provide simple adaptations of the SD algorithm. We consider how the blind detector performs under mismatch, generalize the basic data detectors to nonunitary constellations, and extend them to systems with pilots and virtual carriers. Simulations show that our data detectors perform well.Index Terms-Channel estimation, orthogonal frequency-division multiplexing (OFDM), sphere decoding (SD).

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“…This paper mainly focused on the antenna diversity technique. In [6,10], the authors proposed space time frequency coding schemes to implement MIMO at the transmitter with multiple antennas and the design of receiver with efficient signal processing. In [27], they proposed space time frequency coding with the combination of OFDM to achieve MIMO optimization.…”

Section: Introductionmentioning

confidence: 99%

Hardware Implementation of MISO on Orthogonal Frequency Division Multiplexing Platform with the Help of Alamouti Algorithm

Kilaru¹

2017

International Journal of Electronics and Telecommunications

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Abstract-Many software based OFDM techniques were proposed from last half decade to improve the performance of the system. This paper tried to implement the same with Hardware implementation. We created Hardware based MISO platform with OFDM. We implemented Alamouti algorithm on this test bed. The test bed is implemented with the help of Field Programmable Gate Array (FPGA). The test bed is functionalized with the help of FPGA through Xilinx based system generator for DSP. In this paper we considered the 2×1 MISO implementation with Alamouti algorithm. The simulation results showed that BER and SNR are considerably high for MISO than SISO. The results also proved that proposed OFDM based Alamouti implementation for MISO is excellent in all performance criterions.

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Pilot Spacing in Orthogonal Frequency Division Multiplexing Systems on Practical Channels

Cited by 16 publications

References 7 publications

Multicarrier Communication Over Underwater Acoustic Channels With Nonuniform Doppler Shifts

Multicarrier Communication Over Underwater Acoustic Channels With Nonuniform Doppler Shifts

Joint data detection and channel estimation for OFDM systems

Hardware Implementation of MISO on Orthogonal Frequency Division Multiplexing Platform with the Help of Alamouti Algorithm

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