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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: An adaptive DFSVQ scheme is also proposed in which, when encoding an input vector, first the sub-codebook is searched for a matching codevector to satisfy a pre-specified waveform distortion.
Abstract: A vector quantization (VQ) scheme with finite memory called dynamic finite-state vector quantization (DFSVQ) is presented The encoder consists of a large codebook, so called super-codebook, where for each input vector a fixed number of its codevectors are chosen to generate a much smaller codebook (sub-codebook) This sub-codebook represents the best matching codevectors that could be found in the super-codebook for encoding the current input vector The choice for the codevectors in the sub-codebook is based on the information obtained from the previously encoded blocks where directional conditional block probability (histogram) matrices are used in the selection of the codevectors The index of the best matching codevector in the sub-codebook is transmitted to the receiver An adaptive DFSVQ scheme is also proposed in which, when encoding an input vector, first the sub-codebook is searched for a matching codevector to satisfy a pre-specified waveform distortion If such a codevector is not found in tile current sub-codebook then the whole super-codebook is checked for a better match If a better match is found then a signaling flag along with the corresponding index of the codevector is transmitted to the receiver Both the DFSVQ encoder and its adaptive version are implemented Experimental results for several monochrome images with a super-codebook size of 256 or 512 and different sub-codebook sizes are presented >
63 citations
TL;DR: In this article, beamforming codebooks based on quadrature amplitude modulation (QAM) and phase-shift keying (PSK) constellations are proposed to eliminate the need for storing the codebook.
Abstract: This paper considers the problem of beamforming in multiple-input multiple-output (MIMO) wireless systems. Assuming perfect channel state information at the receiver, the choice of the beamforming vector is made possible through a noiseless limited-rate feedback of one or more bits per coefficient to the transmitter. This paper proposes the use of beamforming codebooks based on quadrature amplitude modulation (QAM) and phase-shift keying (PSK) constellations, which essentially eliminates the need for storage of the codebook. We show that such codebooks perform arbitrarily close to the perfect feedback case as the constellation size increases, and that full diversity order is achieved. We demonstrate an equivalence between the beamforming codebook search problem with that of noncoherent sequence detection. Based on this we propose fast beamforming vector search algorithms. Monte-Carlo simulations are presented to show that the performance is comparable to the best known codebooks, and that the search complexity can be reduced by several orders of magnitude.
63 citations
Patent•
30 Mar 2007TL;DR: In this paper, a spherical lattice codebook is constructed by determining the channel statistics of one or more channels, which can be accomplished by observing a sufficiently large set of channel realizations.
Abstract: Methods and apparatus for designing spherical lattice codebooks for use in data transmission systems are provided. A spherical lattice codebook is constructed by determining the channel statistics of one or more channels, which can be accomplished by observing a sufficiently large set of channel realizations. After determining the channel statistics, an expression for the error probability of the decoder or expressions for bounds on the error probability and expressions for the corresponding gradients are determined. The gradient is then used in an optimization technique to produce a spherical lattice codebook which is subsequently used for transmission.
63 citations
01 Nov 1985
TL;DR: Several vector quantization approaches to the problem of text-dependent speaker verification are described, and detailed experimental results are presented and discussed.
Abstract: Several vector quantization approaches to the problem of text-dependent speaker verification are described. In each of these approaches, a source codebook is designed to represent a particular speaker saying a particular utterance. Later, this same utterance is spoken by a speaker to be verified and is encoded in the source codebook representing the speaker whose identity was claimed. The speaker is accepted if the verification utterance's quantization distortion is less than a prespecified speaker-specific threshold. The best approach achieved a 0.7 percent false acceptance rate and a 0.6 percent false rejection rate on a speaker population comprising 16 admissible speakers and 111 casual imposters. The approaches are described, and detailed experimental results are presented and discussed.
63 citations
11 Jun 1991
TL;DR: The authors summarize a speaker adaptation algorithm based on codebook mapping from one speaker to a standard speaker to be useful in various kinds of speech recognition systems such as hidden-Markov-model-based, feature- based, and neural-network-based systems.
Abstract: The authors summarize a speaker adaptation algorithm based on codebook mapping from one speaker to a standard speaker. This algorithm has been developed to be useful in various kinds of speech recognition systems such as hidden-Markov-model-based, feature-based, and neural-network-based systems. The codebook mapping speaker adaptation algorithm has been much improved by introducing several ideas based on fuzzy vector quantization. This fuzzy codebook mapping algorithm is also applicable to voice conversion between arbitrary speakers. >
63 citations