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In this paper, a new trend of Space Time Block codes-Orthogonal Frequency Division Multiplexing (STBC-OFDM) with Convolutional and Turbo codes. The applied method is based on Alamouti's scheme. We examine the performance of two, three and four transmitters with one receiver over Nakagami-m fading channel using convolutional and turbo codes using BPSK. Also we examine their performance using turbo...
In this paper, a new trend of Space Time Block codes-Orthogonal Frequency Division Multiplexing (STBC-OFDM) with Convolutional and Turbo codes. The applied method is based on Alamouti's scheme. We examine the performance of two, three and four transmitters with one receiver over Nakagami-m fading channel using convolutional and turbo codes using different types of modulation such as BPSK and 64-QAM...
A novel constellation mapping VBLAST zero forcing detection algorithm in MIMO-OFDM system is proposed in this paper. First, the signal is cycled and successively mapped from the whole space of constellation points and is regarded as the first the underlying detection signals to maximize the performance of the first detection layers at the receiver. Then, the traditional ZF detection algorithm is used...
In this paper, we study the performance of the channel estimation in a Turbo coded, orthogonal frequency division multiplexing (OFDM) with multiple antennas at the receiver. We survey the accuracy of the channel estimation for different number of users and different number of pilot subcarriers. Moreover, since there is not a closed form solution to the BER of the Turbo coded system for different number...
Two rate-one differential quasi-orthogonal space-frequency trellis codes (DQOSFTCs) for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) channels are proposed. The DQOSFTCs are systematically constructed within an OFDM symbol period, by combining unitary quasi-orthogonal trellis codes and differential modulation over the frequency domain (DF-QOSFTC) or time domain...
In this paper, a subcarrier-phase control based peak-to-average power (PAPR) reduction scheme without side-information transmission is proposed for LDPC coded OFDM systems. On the transmitter side, peak power of OFDM signal is reduced by multiplying the selected phase-sequence. On the receiver side, the phase sequence used for PAPR reduction is estimated without side information by utilizing the decoding...
In this paper we introduce an improved version of the turbo layered orthogonal lattice detector (T-LORD), recently presented. This implementation, namely K-Best T-LORD, misses the performance of the turbo MAP detector by only few tenths of dB in various configurations, like the fully enhanced T-LORD. However, its complexity is quadratic in the number of transmitting antennas instead of exponential...
We propose a novel adaptive interleaving scheme for orthogonal frequency division multiplexing (OFDM) systems. Based on the channel state information, the approach selects one interleaver from a pool of candidate interleavers. As the selected one is expected to have larger minimum Euclidean distance (MED) at receiver, the technique can significantly improve the decoding error rate performance. Compared...
Unlike symbol decoding and channel decoding, which perform a variety of computationally simple or complex algorithms in the T-DMB baseband receiver, time de-interleaving simply moves data between two buffers according to a specified rule. Nonetheless, such simple data movement consumes considerable processing power if the T-DMB baseband receiver is implemented in software running on a digital signal...
This paper presents a practical low-density parity-check (LDPC) coded OFDM system designed for the underwater acoustic channel with its attendant multipath channel and large Doppler shift. The Doppler shift and channel state information (CSI) are assumed unavailable to both to the transmitter and the receiver. Due to the slow speed of sound in water, even small platform motions can affect the performance...
We present a PMD compensation scheme suitable for use in multilevel coded-modulation schemes, with PMD compensation efficiency comparable to that of OFDM, but with lower complexity of both transmitter and receiver. It is based on Alamouti-type polarization-time coding, with LDPC codes as channel codes.
In this paper, we first propose a novel system that combines multi-code spread spectrum modulation (McM) technique with orthogonal frequency division multiplexing (OFDM) employing quadrature amplitude modulation (QAM). This system provides high data transmission rate without reducing spectral efficiency and overcomes the adverse effects of frequency-selective Rayleigh fading by applying a minimum...
We study the effect of narrowband interference on the error rate of coded multicarrier systems operating over frequency-selective, quasi-static fading channels with non-ideal interleaving. For this purpose we model the interfering signal as a sum of tone interferers, and develop an error-rate estimation method to approximate the performance of the system over each realization of the channel. This...
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