We propose a new space-time block coding (STBC) for asynchronous cooperative systems in full-duplex mode. The orthogonal frequency division multiplexing (OFDM) transmission technique is used to combat the timing error...
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We propose a new space-time block coding (STBC) for asynchronous cooperative systems in full-duplex mode. The orthogonal frequency division multiplexing (OFDM) transmission technique is used to combat the timing errors from the relay nodes. At the relay nodes, only one OFDM time slot is required to delay for a pair-wise symbol swap operation. The decoding complexity is lower for this new STBC than for the traditional quasi-orthogonal STBC. Simulation results show that the proposed scheme achieves excellent performances.
Error correction codes are commonly used in memories to ensure that data are not corrupted. Single error correction double error detection (SEC-DED) codes are among the most widely used codes to protect memories. One ...
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Error correction codes are commonly used in memories to ensure that data are not corrupted. Single error correction double error detection (SEC-DED) codes are among the most widely used codes to protect memories. One common technique to implement SEC-DED codes is to construct a parity check matrix with odd-weight columns. This ensures that double errors have an even weight syndrome and therefore are not confused with single errors thus providing the DED feature. Recently, a technique that reduces the decoding complexity for odd-weight SEC-DED codes has been proposed. This technique can be used only for small data block sizes being the practical limit 32 bits. However, memories with 64 bits are commonly found in modern computing systems. Therefore, it would be advantageous to also reduce the decoding complexity for larger block sizes. A scheme to optimise the decoding of odd-weight SEC-DED codes with block sizes of 64 bits is presented and evaluated. The results show that the new scheme can provide significant reductions in the decoder circuitry area and delay.
This paper describes an efficient method to generate compressed video streams with low complexitydecoding requirements. This is particularly targeted at portable media. players;where the use of such video streams lea...
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ISBN:
(纸本)9789077381380
This paper describes an efficient method to generate compressed video streams with low complexitydecoding requirements. This is particularly targeted at portable media. players;where the use of such video streams leads to reduced power consumption thus extending the battery life. The proposed method is based on the fact that motion compensation is the 'most complex operation in standard H.264/AVC video decoders, mainly because of the operations involved in computing sub-pixel predictions. By using a measure of the computational complexity needed to decode a stream and including it in the encoder cost function used to select the type of sub-pixel motion vector, it is shown that the decoding complexity of compressed video streams can be reduced with negligible penalty in rate-distortion performance. The experimental results show that such optimized constrained coding method is capable of achieving significant decoding complexity reduction at the expense of negligible PSNR loss within the range of bit rates with practical interest.
In multi-user video (MUV) delivery scenarios,the available resources of receiver devices,such as processing capability,link packet error rate (PER),and bandwidth,are usually *** propose a relay-assisted hierarchical a...
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In multi-user video (MUV) delivery scenarios,the available resources of receiver devices,such as processing capability,link packet error rate (PER),and bandwidth,are usually *** propose a relay-assisted hierarchical adaptation (RHA) scheme to maximize the total perceptual quality of all users when transmitting video streams coded via scalable video coding (SVC).First,MUV bitstreams are adaptively extracted under the constraints of network bandwidth and individual decoding ***,the relay links are introduced as substitutes of possible bad direct links for packets *** equal opportunity of transmission is allocated to each stream while the packets inside a stream are scheduled according to their *** priorities are determined by the links states and packets loss *** results show that our RHA scheme has significant performance improvements compared with other schemes.
Tail biting trellis codes and block concatenated codes are discussed from random coding arguments. Error exponents and decoding complexity for generalized tail biting (GTB) random trellis codes, and their relationship...
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Tail biting trellis codes and block concatenated codes are discussed from random coding arguments. Error exponents and decoding complexity for generalized tail biting (GTB) random trellis codes, and their relationships are derived, where the GTB trellis codes consist of full tail biting (FTB) trellis codes, partial tail biting (PTB) trellis codes and direct truncated (DT) trellis codes. We show that the PTB trellis codes at all rates except for low rates are superior to all of the GTB trellis codes, in a sense that they have smaller upper bound on the probability of decoding error for given decoding complexity. We then propose the generalized version of the block concatenated codes constructed by the GTB trellis inner codes, and derive error exponents and the decoding complexity for the proposed code. The results obtained show that the DT trellis inner codes are effective among the GTB trellis inner codes for constructing the generalized version of the concatenated codes to keep the same decoding complexity as the original concatenated codes. We also show that larger error exponents are obtained by the generalized version of concatenated codes, if the decoding complexity is allowed to be larger than that of the original concatenated code, although it is still in polynomial order.
In this correspondence, the error exponents and decoding complexity of binary woven convolutional codes with outer and inner warp are studied. It is shown that for both constructions an error probability that is expon...
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In this correspondence, the error exponents and decoding complexity of binary woven convolutional codes with outer and inner warp are studied. It is shown that for both constructions an error probability that is exponentially decreasing with the memory of the woven convolutional codes can be achieved with a nonexponentially increasing decoding complexity. Furthermore, the error exponent for woven convolutional codes with inner warp is larger than the one for woven convolutional codes with outer warp.
Wireless Robotics has become an important research topic in the last two decades. The need of controlling a robot to perform tasks remotely has significantly increased with the number of applications in fields like me...
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Wireless Robotics has become an important research topic in the last two decades. The need of controlling a robot to perform tasks remotely has significantly increased with the number of applications in fields like medicine and military, among many others. Taking advantage of current standards like Bluetooth and Wifi, Wireless Robotics calls for low power consumption components, robustness and high data rate through the wireless channel. This call can be fulfilled with a reliable signaling format, satisfying the needs of low power consumption and high spectral efficiency. Besides, continuous phase modulation (CPM) has gained increasing attention due to its favorable trade-off between power and bandwidth efficiency. Multi-h CPM recently appeared as a generalization of single-h schemes so as to further decrease the need for bandwidth expansion over the wireless channel. Despite the interesting characteristics of CPM, the decoding of the received signal is particularly difficult in a multi-path wireless environment with no diversity. To provide some level of diversity, several authors have proposed to combine CPM with space-time block coding. A new family of codes for CPM, based on -orthogonality was recently introduced in Hesse et al. (IEEE Trans Commun 59(11): 3158-3166, 2011). These full rate codes achieve full diversity and a low decoding complexity. In this paper, we detail a non trivial extension of these -orthogonal space-time codes using multi-h signaling schemes. These new codes still achieve full diversity but a better spectral compactness by utilizing the available communication bandwidth more efficiently. Also, the decoding complexity is greatly decreased by using only one correlation filter bank for the detection of all transmitted signals.
Quantization index modulation (QIM) principle has shown superior performance in digital watermarking over spread-spectrum and low-bit(s) modulation based methods. In QIM based data hiding scheme, it is a challenging t...
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ISBN:
(纸本)9781424471379
Quantization index modulation (QIM) principle has shown superior performance in digital watermarking over spread-spectrum and low-bit(s) modulation based methods. In QIM based data hiding scheme, it is a challenging task to embed multiple bits of information into the same set of host signal samples. This work attempts to employ M-ary modulation for multibit QIM watermarking. The watermark embedding process may be divided into two phases. In the first phase, a binary watermark image is spatially dispersed using sequence of number generated by a secret key. In the second phase, host image is decomposed by integer wavelets and the encoded watermark bits are embedded into high-low (HL) and low-high (LH) subbands of DWT-coefficients using M-ary modulation. M-ary modulation is accomplished using near-orthogonal dither generated from the combination of random key, Hadamard matrix and step size. Simulation results show that robustness is increased, at the cost of increase in decoding complexity for high M-value.
Distributed low density lattice codes (D-LDLCs) have been proposed for application in cooperative communication networks. D-LDLCs are able to achieve a higher coding gain than LDLCs under the same code length and tran...
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ISBN:
(纸本)9781728174327
Distributed low density lattice codes (D-LDLCs) have been proposed for application in cooperative communication networks. D-LDLCs are able to achieve a higher coding gain than LDLCs under the same code length and transmission power. However, an efficient decoder for D-LDLCs is still lacking. The state-of-the-art message passing decoder for LDLCs can be extended to decode D-LDLCs, but its complexity analysis requires an asymptotic characterization of the decoding behavior in terms of the convergence of the message variances. In this paper, we prove that as the number of iterations tends to infinity, the message variances converge to some constants determined by the code parameters of D-LDLCs. Based on the convergence analysis of message variances, we can further show that the extended decoder achieves linear complexity with respect to the column degree of the D-LDLC check matrix.
In this paper, we propose a new Distributed Source Coding (DSC) scheme based on Low-Density Parity-Check (LDPC) codes with source revealing rate-adaptation. This scheme consists of LDPC codes which are well designed a...
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ISBN:
(纸本)9781457702518
In this paper, we propose a new Distributed Source Coding (DSC) scheme based on Low-Density Parity-Check (LDPC) codes with source revealing rate-adaptation. This scheme consists of LDPC codes which are well designed at their respective operating rates. The member codes do not need to be designed with any rate-adaptation criterion. Instead, when decoding fails, source revealing method is used. Numerical results show that the proposed scheme performs within average 5.6% of the Slepian-Wolf bound over the entire compression rate region. The decoding complexity also dramatically decreases by 57%.
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