This study proposes a system that employs multilevel coding scheme with dynamic space-time trellis codes (DSTTCs) as component codes in order to cooperatively transmit the information of mobile nodes to a common desti...
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This study proposes a system that employs multilevel coding scheme with dynamic space-time trellis codes (DSTTCs) as component codes in order to cooperatively transmit the information of mobile nodes to a common destination node. Perfect channel state information is available at both transmitter and receiver. Every mobile node has a DSTTC encoder at each information level, which receives feedback information from destination node and adapts to the current channel conditions by modifying its code set of generator sequences. The feedback information is in the form of an index of predefined channel profile with power gain in close proximity to the power gain of current channel profile at destination node. The proposed cooperative multilevel dynamic space-time trellis coding (CMLDSTTC) system has the potential of improving spectral efficiency, system throughput, diversity gain, coding gain with low decoding complexity. The CMLDSTTC system outperforms cooperative multilevel space-time trellis coding (CMLSTTC) system with predefined space-time trellis codes and non-cooperative multilevel dynamic space-time trellis coding system by similar to 5 and similar to 2.5 dB, respectively, at frame error rate of 10(-2) using two transmit and two receive antennas. The performance of CMLDSTTC system improves further with an increase in the bits of feedback information.
The informed dynamic scheduling (IDS) strategies, in which the edge message with the maximum message-residual is updated preferentially, achieve remarkable error-correction performance when applied to low-density pari...
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The informed dynamic scheduling (IDS) strategies, in which the edge message with the maximum message-residual is updated preferentially, achieve remarkable error-correction performance when applied to low-density parity-check (LDPC) codes. However, the IDS strategies incur inferior convergence in iterative decoding owing to the greedy problem, which is called the update-relayed trend here. In order to solve the greediness, two locally informed dynamic scheduling algorithms based on the law of large numbers are proposed. The proposed decoding algorithms use random select of check nodes over a predefined update range (RSPUR) which effectively suppresses the propagation of the update-relayed trend and accordingly restrains the forming of multi-update cycles. Moreover, the decoding algorithm is further improved based on random select of check nodes over an adjustable update range (RSCAR). The update ranges are selected based on the law of large numbers. Therefore, the computational resources can be allocated more equitably by increasing iterations. Simulation results show that both the proposed algorithms achieve excellent performance in terms of throughput and convergence with low decoding complexity over the Additive White Gaussian Noise (AWGN) and the fading channels compared to the previous IDS strategies. Hence, the proposed algorithms behave excellently over the wireless channels.
In this paper, a low-complexity suboptimal decoder for coherent and non-coherent quasi-orthogonal space time block codes with three and four transmit antennas is proposed. Our decoder enjoys a nearly linear complexity...
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In this paper, a low-complexity suboptimal decoder for coherent and non-coherent quasi-orthogonal space time block codes with three and four transmit antennas is proposed. Our decoder enjoys a nearly linear complexity and approximately the same performance as the optimal maximum-likelihood (ML) decoder. Simulations show the advantages of the proposed decoder with respect to several other popular approaches to the coherent and non-coherent decoding.
A cyclotomic coset approach for constructions of irregular nonbinary quasi-cyclic low-density parity-check (QC-LDPC) codes of short length is proposed. QC-LDPC codes obtained by this method perform reasonably well ove...
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ISBN:
(纸本)9781467321969
A cyclotomic coset approach for constructions of irregular nonbinary quasi-cyclic low-density parity-check (QC-LDPC) codes of short length is proposed. QC-LDPC codes obtained by this method perform reasonably well over the additive white Gaussian noise (AWGN) channel with iterative decoding in terms of bit-error performance, error-floor, and decoding convergence with low decoding complexity.
Rate-splitting, in which rates are split into smaller rates and successive decoding is used, has been developed for memoryless multiple access channels (MACs). This scheme realizes any rate in the capacity region of a...
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ISBN:
(纸本)9781457705953
Rate-splitting, in which rates are split into smaller rates and successive decoding is used, has been developed for memoryless multiple access channels (MACs). This scheme realizes any rate in the capacity region of a MAC with decodingcomplexity proportional to that for single-user codes, even when time-sharing cannot be used. This paper proposes rate-splitting schemes for multiple-receiver channels, such as compound MACs and interference channels. For interference channels, rate-splitting can achieve any rate in the celebrated Han-Kobayashi rate region with low decoding complexity. Rate-splitting is particularly effective in the frame-asynchronous case, and an achievable rate region for the asynchronous IC is given.
In distributed video coding (DVC), the decoder has considerably high computational complexity as compared to the encoder. The side information plays a crucial role in the successful reconstruction of the Wyner-Ziv fra...
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ISBN:
(纸本)9781728167435
In distributed video coding (DVC), the decoder has considerably high computational complexity as compared to the encoder. The side information plays a crucial role in the successful reconstruction of the Wyner-Ziv frame. However, the side information generation process puts a substantial decoding delay due to its high computational complexity. Phase-Based Interpolation (PBI) is introduced in this work for side information generation. The simulated results on different test videos show that the PBI computational complexity remains low for all kinds of videos. It performs 2.5 to 2.7 times faster than motion-compensated temporal Interpolation (MCTI) with an average acceptable loss of 4.5-5.1 dB in PSNR and 0.09-0.11 dB in SSIM while preserving the structure and sharpness in interpolated frames.
A partition-level adaptive sub-pixel interpolation filter method for video coding is proposed in this paper. Various type of interpolation filters are exploited to compensate the limited motion accuracy represented by...
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ISBN:
(纸本)9781424442904
A partition-level adaptive sub-pixel interpolation filter method for video coding is proposed in this paper. Various type of interpolation filters are exploited to compensate the limited motion accuracy represented by motion vector or improve interpolation performance of directional textures inconsistent with motion direction, an optimal filter is selected as sub-pixel interpolation filter for each macroblock partition by the principle of Rate Distortion Optimization. The method is implemented in AVS reference software, experimental results show that by utilizing this method, the compression performance is improved up to 0.5dB, and the decodingcomplexity of motion compensation is decreased up to 20%.
A class of rate-one space-time block codes (STBC) allowing the decoding of transmitted symbols into four groups is recently proposed by Yuen, Guan and Tjhung. This code is called four-group decodable STBC (4Gp-STBC). ...
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ISBN:
(纸本)9781424405688
A class of rate-one space-time block codes (STBC) allowing the decoding of transmitted symbols into four groups is recently proposed by Yuen, Guan and Tjhung. This code is called four-group decodable STBC (4Gp-STBC). In this paper, the equivalent channel of 4Gp-STBC is derived and a new method to decode 4Gp-STBC based on sphere decoders is presented. Furthermore, the performance of 4Gp-STBC is analyzed. A New signal rotation method is proposed, which performs better than the existing one.
In this paper, the performance limit of lattice sequential decoder for coded M x N MIMO channel is analysed. We determine the rates achievable by lattice coding and sequential decoding applied to such channel. The div...
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ISBN:
(纸本)9781424456383
In this paper, the performance limit of lattice sequential decoder for coded M x N MIMO channel is analysed. We determine the rates achievable by lattice coding and sequential decoding applied to such channel. The diversity-multiplexing trade-off under lattice sequential decoding is derived as a function of its parameter-the bias term. Such parameter is critical for controlling the amount of computations required at the decoding stage. Achieving low decoding complexity requires increasing the value of the bias term. However, this is done at the expense of losing the optimal trade-off of the channel. We show how such decoder can bridge the gap between lattice decoder and lowcomplexity decoders [e. g., minimum mean-square error successive interference cancellation (MMSE-SIC)]. We argue that, MMSE-SIC may achieve close to the maximum diversity gain of the channel MN at very low multiplexing gain.
The ARM7 NEON processor with 128bit SIMD hardware accelerator requires a peak performance of 13.99 Mega Cycles per Second for MP3 stereo entertainment quality decoding. For similar compression bit rate, OGG and AAC is...
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ISBN:
(纸本)9780819499479
The ARM7 NEON processor with 128bit SIMD hardware accelerator requires a peak performance of 13.99 Mega Cycles per Second for MP3 stereo entertainment quality decoding. For similar compression bit rate, OGG and AAC is preferred over MP3. The Patent Cooperation Treaty Application dated 28/August/2012 describes an audio decompression scheme producing a sequence of interleaving "min to Max" and "Max to min" rising and falling segments. The number of interior audio samples bound by "min to Max" or "Max to min" can be {0|1| ... |N} audio samples. The magnitudes of samples, including the bounding min and Max, are distributed as normalized constants within the 0 and 1 of the bounding magnitudes. The decompressed audio is then a "sequence of static segments" on a frame by frame basis. Some of these frames needed to be post processed to elevate high frequency. The post processing is compression efficiency neutral and the additional decodingcomplexity is only a small fraction of the overall decodingcomplexity without the need of extra hardware. Compression efficiency can be speculated as very high as source audio had been decimated and converted to a set of data with only "segment length and corresponding segment magnitude" attributes. The PCT describes how these two attributes are efficiently coded by the PCT innovative coding scheme. The PCT decoding efficiency is obviously very high and decoding latency is basically zero. Both hardware requirement and run time is at least an order of magnitude better than MP3 variants. The side benefit is ultra low power consumption on mobile device. The acid test on how such a simplistic waveform representation can indeed reproduce authentic decompressed quality is benchmarked versus OGG(aoTuv Beta 6.03) by three pair of stereo audio frames and one broadcast like voice audio frame with each frame consisting 2,028 samples at 44,100KHz sampling frequency.
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