H.264/AVC employs a rate-distortion (RD) optimisation technique to determine the best coding mode for each macroblock (MB). An intra-mode skip decision algorithm is presented based on RD costs of the SUB8 x 8 mode and...
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H.264/AVC employs a rate-distortion (RD) optimisation technique to determine the best coding mode for each macroblock (MB). An intra-mode skip decision algorithm is presented based on RD costs of the SUB8 x 8 mode and the I4MB mode to reduce the processing time. Experimental results on test video sequences show that the computational complexity has been reduced by about 20%, with nearly negligible loss of peak signal-to-noise ratio (PSNR) value.
A turbo frequency domain equalisation (T-FDE) scheme for space frequency block-coded (SFBC) single-carrier systems is proposed. The received signal is space-frequency decoded first, then the T-FDE is performed, which ...
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A turbo frequency domain equalisation (T-FDE) scheme for space frequency block-coded (SFBC) single-carrier systems is proposed. The received signal is space-frequency decoded first, then the T-FDE is performed, which exchanges extrinsic information between the minimum mean square error (MMSE)-based frequency domain equaliser (FDE) and the decoder according to the turbo principle. The simulation results demonstrate that better performance can be achieved using the proposed scheme compared with non-iterative detection.
An n x n matrix A is said to be silver if, for i = 1, 2,..., n, each symbol in {1, 2,..., 2n-1} appears either in the ith row or the ith column of A. The 38th International Mathematical Olympiad asked whether a silver...
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An n x n matrix A is said to be silver if, for i = 1, 2,..., n, each symbol in {1, 2,..., 2n-1} appears either in the ith row or the ith column of A. The 38th International Mathematical Olympiad asked whether a silver matrix exists with n = 1997. More generally, a silver cube is a triple (K-n(d), I, c) where I is a maximum independent set in a Cartesian power of the complete graph K-n, and c : V (K-n(d)) -> {1, 2,..., d(n - 1) + 1} is a vertex colouring where, for v epsilon I, the closed neighbourhood N[v] sees every colour. Silver cubes are related to codes, dominating sets, and those with n a prime power are also related to finite geometry. We present here algebraic constructions, small examples, and a product construction. The nonexistence of silver cubes for d = 2 and some values of n, is proved using bounds from coding theory.
Principal component analysis (PCA) can be used to encode video sequences at extremely low bit rates, e.g. 34.6dB (PSNR) at 4.2 kbit/s. The same eigenvectors are used for encoding and decoding for this coding. Introduc...
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Principal component analysis (PCA) can be used to encode video sequences at extremely low bit rates, e.g. 34.6dB (PSNR) at 4.2 kbit/s. The same eigenvectors are used for encoding and decoding for this coding. Introduced is a coding scheme where eigenvectors for only part of the video frames are used for encoding but the eigenvectors for the entire frame are used for decoding. This is called asymmetric PCA coding. This reduces the complexity of encoding by approximate to 5 times and at the same time increases the reconstruction quality for the facial part of the video with 0.4 dB (PSNR).
A novel, fast decoder for the binary quadratic residue code of length 23, or equivalently the famous Golay code is proposed. The core is a new idea to determine the syndrome weight. The decoding algorithm can be imple...
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A novel, fast decoder for the binary quadratic residue code of length 23, or equivalently the famous Golay code is proposed. The core is a new idea to determine the syndrome weight. The decoding algorithm can be implemented with a parallel design, and the decoder based on this algorithm is not only very efficient but also of low area cost. It promises a binary Golay decoder which is faster than available decoders.
Dense coding is arguably the protocol that launched the field of quantum communication(1). Today, however, more than a decade after its initial experimental realization(2), the channel capacity remains fundamentally l...
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Dense coding is arguably the protocol that launched the field of quantum communication(1). Today, however, more than a decade after its initial experimental realization(2), the channel capacity remains fundamentally limited as conceived for photons using linear elements. Bob can only send to Alice three of four potential messages owing to the impossibility of carrying out the deterministic discrimination of all four Bell states with linear optics(3,4), reducing the attainable channel capacity from 2 to log(2) 3 approximate to 1.585 bits. However, entanglement in an extra degree of freedom enables the complete and deterministic discrimination of all Bell states(5-7). Using pairs of photons simultaneously entangled in spin and orbital angular momentum(8,9), we demonstrate the quantum advantage of the ancillary entanglement. In particular, we describe a dense-coding experiment with the largest reported channel capacity and, to our knowledge, the first to break the conventional linear-optics threshold. Our encoding is suited for quantum communication without alignment(10) and satellite communication.
A node-by-node joint multi-user iterative decoding strategy, instead of the detector-decoder loop strategy, is proposed based on the factor graph representation of the LDPC-coded IDMA system. To analyse the proposed i...
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A node-by-node joint multi-user iterative decoding strategy, instead of the detector-decoder loop strategy, is proposed based on the factor graph representation of the LDPC-coded IDMA system. To analyse the proposed iterative decoding process, a Gaussian approximation based density evolution algorithm is designed. The degree distributions of LDPC codes are optimised for the IDMA system when the system bandwidth efficiency is 1.
This paper develops a method to obtain a Gilbert-Varshamov type bound for dense packings in the Euclidean spaces using suitable lattices. For the Leech lattice the obtained bounds are quite reasonable for large dimens...
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This paper develops a method to obtain a Gilbert-Varshamov type bound for dense packings in the Euclidean spaces using suitable lattices. For the Leech lattice the obtained bounds are quite reasonable for large dimensions, better than the Minkowski-Hlawka bound, but not as good as the lower bound given by Keith Ball in 1992.
Various causal details of the genetic process of translation have been singled out to account for its privileged status as a 'code'. We explicate the biological uses of coding talk by characterizing a class of...
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Various causal details of the genetic process of translation have been singled out to account for its privileged status as a 'code'. We explicate the biological uses of coding talk by characterizing a class of special causal processes in which topological properties are the causally relevant ones. This class contains both the process of translation and communication theoretic coding processes as special cases. We propose a formalism in terms of graphs for expressing our theory of biological codes and discuss its utility in understanding biological systems.
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