Topic
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: Simulation results show that the developed joint iterative training method having a fast convergence can achieve similar array gain compared with the systems equipped with the continuous PSs, and the proposed hybrid precoding utilizing low-resolution PSs can offer a sum-rate comparable to the fixed-rank fully-digital multiple-input multiple-output systems, but with limited hardware cost and energy consumption.
Abstract: Large antenna array systems are favored in next-generation wireless communications, as it can offer multiplexing and array gains that enhance the system sum-rate. However, the large antenna array systems often necessitate the use of high-cost and power-hungry radio frequency (RF) devices. To reduce the hardware complexity and avoid the explicit high-dimensional channel estimation, we propose a joint iterative training based hybrid precoding using low-resolution phase shifters (PSs). Different from the existing works based on the predefined codebook, the iterative training is applied for the hybrid architectures. The iterative training converges to the dominant steering vectors that align with the direction of the largest channel gain, thus it can harvest more array gains than the predefined codebook method. In addition, the performance loss induced by the finite phase quantization is analytically investigated for multiple RF chains. Simulation results show that the developed joint iterative training method having a fast convergence can achieve similar array gain compared with the systems equipped with the continuous PSs. Furthermore, the proposed hybrid precoding utilizing low-resolution PSs can offer a sum-rate comparable to the fixed-rank fully-digital multiple-input multiple-output systems, but with limited hardware cost and energy consumption.
31 citations
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09 Jan 2004
TL;DR: In this article, the authors propose a method and apparatus for a voice transcoder that converts a bitstream representing frames of data encoded according to a first voice compression standard to a binary representation of the data using perceptual weighting that uses tuned weighting factors to produce a higher quality decoded voice signal than a comparable tandem transcoding solution.
Abstract: A method and apparatus for a voice transcoder that converts a bitstream representing frames of data encoded according to a first voice compression standard to a bitstream representing frames of data according to a second voice compression standard using perceptual weighting that uses tuned weighting factors, such that the bitstream of a second voice compression standard to produce a higher quality decoded voice signal than a comparable tandem transcoding solution. The method includes pre-computing weighting factors for a perceptual weighting filter optimized to a specific source and destination codec pair, pre-configuring the transcoding strategies, mapping CELP parameters in the CELP parameter space according to the selected coding strategy, performing Linear Prediction analysis if specified by the transcoding strategy, perceptually weighting the speech using with tuned weighting factors, and searching for adaptive codebook and fixed-codebook parameters to obtain a quantized set of destination codec parameters.
31 citations
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02 May 2011TL;DR: In this article, a multiple-input multiple-output (MIMO) communication system using a first codebook and a second codebook is considered, where a receiver may extract a first precoding matrix indicator from the first code book, and may then extract a second precoding Matrix Indicator from the second code book.
Abstract: A multiple input multiple output (MIMO) communication system using a first codebook and a second codebook is provided. The first codebook and the second codebook may independently exist, or may exist in a form of an overall codebook in which the first codebook and the second codebook are integrated with each other. A receiver may extract a first precoding matrix indicator from the first codebook, and may extract a second precoding matrix indicator from the second codebook. The receiver may also extract the first precoding matrix indicator and the second precoding matrix indicator from the overall codebook. The first precoding matrix indicator and the second precoding matrix indicator may be fed back to a transmitter. The transmitter may determine a precoding matrix based on the first precoding matrix indicator and the second precoding matrix indicator.
31 citations
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25 Jan 1991TL;DR: In this article, an individual desiring to operate a pager via voice commands sends a message to a repository of voice recognition codebooks requesting access to a particular codebook, and the repository devices respond by transmitting the codebook of that individual to at least one pager, which stores the codebooks therein.
Abstract: An individual desiring to operate a pager via voice commands sends a message to a repository of voice recognition codebooks requesting access to a particular codebook. The repository device(s) respond by transmitting the codebook of that individual to at least one pager, which stores the codebook therein. In a second embodiment, each individual operating a pager by voice commands is provided with a codebook module, which contains suitable memory storage having at least that operator's codebook stored therein. By inserting the codebook module (or card) into the pager, that pager becomes at least partially controllable by the voice commands of that operator. The codebook module may be easily removed to permit the communication device to be rapidly reprogrammed by inserting the codebook of another operator.
31 citations
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01 Apr 1985TL;DR: An application of source coding to speaker recognition is described, where each speaker is represented by a sequence of vector quantization codebooks; known input utterances are classified using these codebook sequences and the resulting classification distortion is compared to a rejection threshold.
Abstract: An application of source coding to speaker recognition is described. The method is text-dependent - the text spoken is known, and the problem is to determine who said it. Each speaker is represented by a sequence of vector quantization codebooks; known input utterances are classified using these codebook sequences and the resulting classification distortion is compared to a rejection threshold. On a 16 speaker test population with an additional 111 imposters, this method achieved a false rejection rate of 0.8%, an imposter acceptance rate of 1.8%, and within the 16 speakers, an identification error rate of 0.0%.
31 citations