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Codebook
About: Codebook is a research topic. Over the lifetime, 8492 publications have been published within this topic receiving 115995 citations.
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TL;DR: In this paper, an approximate message passing decoder for sparse superposition codes was proposed, whose decoding complexity scales linearly with the size of the design matrix, and the decoder was rigorously analyzed and it was shown to asymptotically achieve the AWGN capacity with an appropriate power allocation.
Abstract: Sparse superposition codes were recently introduced by Barron and Joseph for reliable communication over the additive white Gaussian noise (AWGN) channel at rates approaching the channel capacity. The codebook is defined in terms of a Gaussian design matrix, and codewords are sparse linear combinations of columns of the matrix. In this paper, we propose an approximate message passing decoder for sparse superposition codes, whose decoding complexity scales linearly with the size of the design matrix. The performance of the decoder is rigorously analyzed and it is shown to asymptotically achieve the AWGN capacity with an appropriate power allocation. Simulation results are provided to demonstrate the performance of the decoder at finite blocklengths. We introduce a power allocation scheme to improve the empirical performance, and demonstrate how the decoding complexity can be significantly reduced by using Hadamard design matrices.
88 citations
Patent•
17 Aug 2005TL;DR: In this article, a closed-loop transmit precoding between a transmitter and a receiver is proposed, where the receiver determines which precoding rotation matrix from the codebook should be used for each subcarrier that has been received.
Abstract: A method for providing closed-loop transmit precoding between a transmitter and a receiver, includes defining a codebook that includes a set of unitary rotation matrices (202). The receiver determines which precoding rotation matrix from the codebook should be used for each sub-carrier that has been received (204). The receiver sends an index to the transmitter (206), where the transmitter reconstructs the precoding rotation matrix using the index, and precodes the symbols to be transmitted using the precoding rotation matrix (208). An apparatus that employs this closed-loop technique is also described.
88 citations
TL;DR: The apparatus comprises a linear mapping function codebook used for converting spectral parameters, and a weights calculator and an adder for weighing and summing function outputs for expanding the bandwidth of speech signals.
Abstract: Apparatus for expanding the bandwidth of speech signals such that a narrowband speech signal is input and digitized, the spectral envelope information and residual information are extracted from the digitized signal by linear predictive coding analysis, the spectral envelope information is expanded into wideband information by a spectral envelope converter, the residual information is expanded into wideband information by a residual converter, the converted spectral envelope information and residual information are combined to produce a wideband speech signal, frequency information not contained in the input signal is extracted from the obtained wideband speech signal by a filter, and the resulting signal is added to the original digitized input signal, and the obtained signal is converted into an analog signal as the output signal of the apparatus. The apparatus comprises a linear mapping function codebook used for converting spectral parameters, and a weights calculator and an adder for weighing and summing function outputs.
87 citations
TL;DR: A novel framework for human action recognition based on Bag of Words (BoWs) action representation is proposed, that unifies discriminative codebook generation and discriminant subspace learning.
87 citations
TL;DR: This paper compares four approaches to achieve a compact codebook vocabulary while retaining categorization performance and investigates the trade-off between codebook compactness and categorizationperformance.
87 citations