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We investigate performance limits of a coded asymmetric OFDM (A-OFDM) system in multipath fading channels when maximum-likelihood (ML) detection is deployed. Our A-OFDM formulation is general and the analysis extends to coded OFDM (COFDM), precoded COFDM and single carrier systems. At first, an exact pairwise error probability is evaluated based on Craig's alternative form of the Q-function. Then...
Filter banr design for wavelet compression schemes is very important. Although, JPEG2000 standard adopted bi-orthogonal 9/7-tap Daubechies wavelet, it is experimentally shown that this banr is well suited for natural images, which they have small amount of energy in the high frequency in horizontal and vertical directions. In this paper, we introduce a method for filter banr design according to power...
In this work, we propose a new decoding algorithm to correct closed-chains error patterns in hard-input hard-output (HIHO) turbo product codes (TPC). The proposed technique is based on correlating the horizontal and vertical component codes to estimate the location of the erroneous bits in the closed-chain of errors, then erasure decoding is used to correct the closed-chain of errors. Simulation results...
Non-Binary Low Density Parity Check (NB-LDPC) codes are expected to reduce the performance gap between binary LDPC and Turbo Codes for both short and medium length codewords, retaining in both cases the best of each. This paper presents the performance evaluation of NB-LDPC when compared to state-of-art channel coding techniques, namely Convolutional Turbo Codes (CTC) and Quasi-Cyclic LDPC. The performance...
This paper presents a power consumption comparison of a novel approach to video compression based on distributed video coding (DVC) and widely used video compression based on H.264/AVC standard. We have used a low-complexity configuration for H.264/AVC codec. It is well-known that motion estimation (ME) and CABAC entropy coder consume much power so we eliminate ME from the codec and use CAVLC instead...
An overview of the new Multiview Video Coding (MVC) extension of the H.264/AVC standard is given in this paper. The benefits of multiview video coding are examined by encoding two data sets captured with multiple cameras. These sequences were encoded using MVC reference software and the results are compared with references obtained by encoding multiple views independently with H.264/AVC reference...
This paper studies six half-duplex cooperative relaying schemes with one multi-hop beamforming scenario in the 60 GHz band. Five of them are known. One new scheme is modified based on superposition coding. Under this scenario, we make the achievable rate expressions of the studied relaying schemes. By using these expressions, the comparison is made in terms of achievable rate versus relay-node position...
Interleave-division multiple access systems (IDMA) has been extensively studied. In this paper, we present the performance analysis of anti-jamming for IDMA systems. The theoretic analysis and simulation results show that the performance of anti-jamming for IDMA systems is related to spread gain, code-bit rate, and the number of iterations, respectively. And our research work can provide a reference...
Video encoding rate control has been the research focus in the recent years. The existing rate control algorithms use Rate-Distortion (R-D) or Rate-Quantization (R-Q) models. These latter assume that the enhancement of the bit allocation process, the quantization parameter determination and the buffer management are essentially based on the improvement of complexity measures estimation. Inaccurate...
Increasingly, we can obtain more than one compressed copy of the same video content with different levels of visual quality over the Internet. As the original source video is not always available, how to choose or derive a video of the best quality from these copies becomes a challenging and interesting problem. In this paper, we address this new research problem by blindly enhancing the quality of...
Originally, hierarchical prediction structures were proposed to achieve temporal scalability. Soon after, it was realized that with a proper quantization parameter cascading (QPC) scheme the general performance can be significantly improved by hierarchical coding. However, the theory behind the gain has not been explored so far. In this paper, the QPC in hierarchical coding is investigated by model...
H.264/AVC has brought an important increase in coding efficiency in comparison to previous video coding standards. One of its features is the use of macroblock partitioning in a tree-based structure. The use of macroblock partitions based in arbitrary line segments, like wedge partitions, has been reported to increase coding gains. The main problem of these non-standard new partitions schemes is the...
This paper presents a novel multi-functional MultipleInput Multiple-Output (MIMO) scheme that combines the benefits of the Vertical Bell Labs Layered Space-Time (V-BLAST) scheme, of SpaceTime Codes (STC) as well as of beamforming. To further enhance the attainable system performance and to maximise the coding advantage of the proposed transmission scheme, the system is also combined with multi-dimensional...
Intra-predictive transforms are a kind of block-based transforms that can exploit both the intra- and inter-block correlations. This paper analyzes the coding gains of intra-predictive transforms for the Gaussian process. The tight upper bound of the coding gain is derived, which is shown to be better than both the discrete cosine transform and the Karhunen Loe??ve transform. The optimal intra-predictive...
Traditional embedded coding systems involve high complexity algorithms, requiring fast and expensive processors. In the last years, several authors have developed very fast and simple non-embedded wavelet encoders that are able to get reasonable good performance with reduced computing requirements. These encoders have lost the SNR scalability and precise rate control capabilities. In this paper, we...
This paper proposes a new technique for constructing the quasi-cyclic low density parity check (QC-LDPC) codes based on row division method. The new codes offer more flexibility in term of girth, code rates and codeword length. In this method of code construction, the rows are used to form as the distance graph. Then they are transformed to a parity-check matrix in order to acquire the desired girth...
In this paper, we focus on multi-user MIMO broadcast channels with few users feeding back their channel estimates, i.e. K linear in the number M of transmitting antennas. Under this condition, the chance of finding a subset of users almost orthogonal vanishes when M gets large. For this reason, we show that the zero forcing (ZF) beamformer, commonly accepted for practical implementations, can be easily...
Demodulation of M-ary quadrature amplitude modulation (M-QAM) requires the receiver to estimate the phase and amplitude of the received signal. The demodulator performance is sensitive to errors in these estimates, and the sensitivity increases as M increases. We examine the effects of phase and amplitude errors on the performance of QAM communication systems with error-control coding and soft-decision...
Cooperative communications has emerged as an efficient realization of multiple input and multiple output (MIMO) systems. To reap the benefits of cooperative communications we follow the block-Markov code book structure. Recently a low cost and efficient operational implementation of block-Markov coding, using network coding, has been proposed. In this paper, we derive the closed form expression for...
In this paper, the structure of a trellis-coded 3-dimensional orthogonal frequency division multiplexing (3-D OFDM) is proposed and its error performance in additive white Gaussian channel is analyzed. We present the set-partitioning of a 3-D 8-ary constellation for trellis coding. As a result, the trellis-coded 3-D OFDM system has around 6 dB coding gain over an uncoded one when an 8-ary constellation...
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