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In this paper, we consider the problem of the Space Frequency Block Codes (SFBC) decoding, according to the Maximum A Posteriori (MAP) criterion when the channel is not perfectly known at the receiver. We propose to use the Expectation Maximization (EM) algorithm to solve this problem. Simulation results show that the performance of our iterative decoder using the EM algorithm is very close to the...
In this paper, a low-complexity iterative receiver combining joint iterative channel estimation with symbol detection is proposed for coded orthogonal frequency division multiplexing (OFDM) systems in fast fading channels with Doppler frequencies up to 15% of the OFDM symbol rate. The receiver exchanges information between the channel estimator and detector in an iterative fashion to obtain accurate...
Zero-Padding Orthogonal Frequency Division Multiplexing (ZP-OFDM) has been proposed as an alternative solution to coded-OFDM, which often incurs high decoding complexity. Various ZP-OFDM receivers have been proposed in the literature, exchanging performance with complexity. On the contrary, we propose in this paper a novel reduced-complexity minimum mean square error (MMSE)-based receiver for ZP-OFDM...
A realistic framework for cooperation diversity is presented for Orthogonal Frequency Division Multiplexing (OFDM) systems with clipping type of transmitter non-linearities. The destination node processes together the received information from the source node and a single, selection algorithm dependent relay one (if any of the candidate relays succeeds in decoding the original OFDM packet sent). The...
Single Carrier Frequency Division Multiplex (SC-FDMA) is the modulation technique being considered in Long Term Evolution (LTE) proposal announced recently. The reason for this stems from the fact that SC-FDMA envelope fluctuation is considerable lower than that of conventional Orthogonal Frequency Division Multiplex (OFDM) technique, thereby results in less sensitivity to the nonlinear distortion...
This paper deals with the Matlab implementation of the DVB-H (Digital Video Broadcasting to Handhelds) channel coding in AWGN (Additive White Gaussian Noise) transmission channel. Developed application structure and its functions are described. Channel encoder and decoder were implemented in Matlab as it is specified in the DVB-H standard. Created application can evaluate and shows two types of BER...
This paper examined the problem of carrier phase recovery in turbo-coded OFDM systems. Then introduced a novel a priori probability aided (APPA) OFDM joint carrier phase recovery and signal detection algorithms to eliminate disadvantage impact brought by phase offset. The algorithms utilized the soft value of the extrinsic information generated by iterative maximum a posteriori (MAP) turbo decoders...
The following topics are dealt with: channel coding; wireless Internet; resource allocation; OFDMA; decoding; cognitive radio; ad hoc network; MIMO communication; mobile WiMax; game theory; cellular network; wireless mesh network; protocols; signal processing; and Global Navigation Satellite System.
Two closed-form blind channel estimators for orthogonally coded multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems are proposed. The key idea of our approaches is to estimate the channel parameters in the time domain instead of doing this in the frequency domain. Our first approach is based on the maximum likelihood (ML) technique with the relaxed finite...
In this paper, we derive a theoretical performance evaluation scheme of Kalman filter based channel tracking and data decoding for multiple-input multiple-output orthogonal frequency division multiplexed (MIMO-OFDM) communication systems that are based on orthogonal space-time block codes. The derivation is approximate, however, it is novel and demonstrated accurate for practical scenarios. Assuming...
Single-carrier frequency-division multiple-access (SC-FDMA) has been adopted in the uplink of the LTE standard due to its lower peak-to-average-power ratio (PAPR) compared to orthogonal frequency-division multiple access (OFDMA). Recent activities in the LTE-advanced (LTE-A) standardization have focused on effective uplink transmit diversity schemes with low PAPR but without considering the performance...
We consider orthogonal frequency division multiplexing (OFDM) for high data rate narrowband power line communication (PLC) in the frequency bands up to 500 kHz. In narrowband PLC, the performance is strongly influenced by the impulsive noise with very large amplitudes with short durations. Simple iterative impulsive noise suppression algorithms can effectively improve the error rate performance in...
Iterative channel estimation and decoding result in significant performance gains but at high computational cost. In this paper, an iterative channel estimation control is proposed to reduce the complexity by only refining the channel estimates which significantly affect the decoding performance. Simulation results demonstrate that significant complexity savings can be achieved with negligible error...
We1 consider transmission over a set of parallel MARCs (multiple-access relay channel) based on the OFDM (Orthogonal Frequency Division Multiplexing) modulation. Two users communicate to a common destination (D) with the help of a relay (R) over a set of parallel channels. The relay operates in decode and forward (repetition coding type) and half duplex modes. The problem considered is the maximization...
The spatial modulation (SM) divides input data into antenna indices and data symbols, and transmits data symbols via the specific antenna chosen by an antenna index. The performance of SM is affected by the worse one between the detection performances of antenna index and data symbol. In this paper, power efficient SM based transmitter and receiver architectures are proposed in order to provide different...
In this paper, we present a 4 × 4 MIMO-OFDM system for wideband video transmission. This video transmission system is modified from the DVB-T system by including the MIMO technique and a proposed LLR-based adaptive hierarchical modulation involving channel SNR and H.264/AVC packet priority. In the proposed system, Reed-Solomen encoder packet format, inner interleaver structure and pilot pattern are...
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...
In order to reduce the peak-to-average power ratio (PAR) of multi-antenna orthogonal frequency-division multiplexing (MIMO OFDM) systems selected mapping (SLM) and its MIMO extensions are considered. With SLM the transmission of some side information is necessary. In this paper, we focus on the approach of embedding the side information into the OFDM frame using combinations of unrotated and ??/4...
Iterative low-density parity-check (LDPC) coded multiple-input multiple-output (MIMO) systems are known to be able to theoretically achieve excellent performance by computer simulation. If the systems can exploit time interleaving long enough to cover a fading cycle, excellent error rate performance should be obtained in mobile line-of-sight (LOS) environments. This paper describes an iterative LDPC...
This work considers the problem of channel estimation in the context of non-binary-LDPC-coded OFDM transmission over doubly-selective multipath channels. The potential of channel encoding is exploited to derive an iterative Wiener-filter-based estimation method using both time and frequency autocorrelation of the channel. The proposed algorithm can use either the soft information or the hard decisions...
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