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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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Patent
Charles W. Bethards1
19 Mar 1990
TL;DR: In this paper, an identification code is employed to access particular voice recognition information (codebook) from a repository of voice recognition codebooks container within the portable programming device, which responds by transmitting the identified codebook to at least one communication device which stores the codebook therein.
Abstract: A communication device may be programmed to recognize voice commands via a portable programming apparatus. An identification code is employed to access particular voice recognition information (codebook) from a repository of voice recognition codebooks container within the portable programming device. The programming device responds by transmitting the identified codebook to at least one communication device, which stores the codebook therein. Thereafter, the communication device may respond to the voice commands of that individual.

31 citations

Proceedings ArticleDOI
TL;DR: In this article, the authors study the channel correlation matrix of a generic ray-based 3D channel model, and demonstrate that the 3D correlation matrix can be well approximated by a Kronecker production of azimuth and elevation correlations.
Abstract: A 2D antenna array introduces a new level of control and additional degrees of freedom in multiple-input-multiple-output (MIMO) systems particularly for the so-called "massive MIMO" systems. To accurately assess the performance gains of these large arrays, existing azimuth-only channel models have been extended to handle 3D channels by modeling both the elevation and azimuth dimensions. In this paper, we study the channel correlation matrix of a generic ray-based 3D channel model, and our analysis and simulation results demonstrate that the 3D correlation matrix can be well approximated by a Kronecker production of azimuth and elevation correlations. This finding lays the theoretical support for the usage of a product codebook for reduced complexity feedback from the receiver to the transmitter. We also present the design of a product codebook based on Grassmannian line packing.

31 citations

Journal ArticleDOI
TL;DR: A novel low-complexity beam training scheme is explored by fully exploiting the sparse nature of the mmWave channel and the strong correlations of large-scale antenna arrays to reduce beam search space.
Abstract: We consider a 5G millimeter-wave (mmWave) massive MIMO system with subconnected hybrid structure, where each transceiver unit (TXRU) is connected to a subarray at the transmitter (TX) or the receiver (RX). Beam training is the first step for codebook-based beamforming in the absence of ideal channel state information (CSI). The complexity of the optimal exhaustive search beam training is exponentially increased with the number of TXRUs (or subarrays) at the TX and the RX, which is infeasible in practice. The conventional beam training schemes are mainly based on the idea of mathematical search algorithms and novel beam codebook designs. In this study, we explore a novel low-complexity beam training scheme by fully exploiting the sparse nature of the mmWave channel and the strong correlations of large-scale antenna arrays. Specifically, we propose a training scheme to reduce beam search space for 5G mmWave system, which consists of the following two key stages: 1) a beam subset optimization method from the perspective of array gain for capturing the energy of dominant channel propagation paths, and 2) a class of linear iterative beam search algorithms within the optimized beam subset utilizing the idea of limiting the degrees of freedom of the subarray indices during beam training. The range of the optimized beam subset size and linear search condition are also given. The performances of the proposed two algorithms, beam subset optimization-single subarray linear search and beam subset optimization-subarray pair linear search, are evaluated in a 5G mmWave system. Analysis has shown that the complexity of the proposed scheme is linear with the number of channel propagation paths, which can considerably reduce the complexity of conventional schemes. Simulation results have verified the near-optimal performance of the proposed schemes when compared with exhaustive search as well as other existing training methods.

31 citations

PatentDOI
TL;DR: A method of encoding speech sounds to facilitate their transmission to and reconstruction at a remote receiver and derives the same combination of filtration parameters which the transmitter applied to its filter while selecting the codebook vector corresponding to the transmitted index.
Abstract: A method of encoding speech sounds to facilitate their transmission to and reconstruction at a remote receiver. A transmitter and a receiver have identical filters and identical codebooks containing prestored excitation vectors which model quantized speech sound vectors. The speech sound vectors are compared with filtered versions of the codebook vectors. The filtered vector closest to each speech sound vector is selected. During the comparison, filtration parameters derived by backward predictive analysis of a series of previously selected filtered codebook vectors are applied to the filter. The transmitter sends the receiver an index representative of the location of the selected vector within the codebook. The receiver uses the index to recover the selected vector from its codebook, and passes the recovered vector through its filter to yield an output signal which reproduces the original speech sound sample. By applying the same backward predictive analysis technique employed by the transmitter to the same series of previously selected filtered codebook vectors to which the transmitter applied the technique, the receiver derives the same combination of filtration parameters which the transmitter applied to its filter while selecting the codebook vector corresponding to the transmitted index.

31 citations

Proceedings ArticleDOI
14 Nov 2005
TL;DR: This paper proposes an optimal order for Walsh transform kernel based on the energy distribution of a particular codebook at each dimension in a k-D Walsh domain, which requires that the dimension with a larger energy distribution be put forward to be as a lower dimension.
Abstract: In a framework of vector quantization (VQ), the encoding speed is a key issue for its practical applications. To speed up the VQ encoding process, Walsh transform is introduced in the previous work to map vectors in a k-dimensional (k-D) spatial domain into k-D Walsh domain in order to exploit the energy-compaction property of an orthogonal transform. However, there still exist a serious problem in that previous work because it just simply used the most common sequency-ordered Walsh transform kernel, which is actually not very high efficient for fast VQ encoding. In order to solve the kernel order problem in VQ encoding this paper proposes an optimal order for Walsh transform kernel based on the energy distribution of a particular codebook at each dimension in a k-D Walsh domain, which requires that the dimension with a larger energy distribution be put forward to be as a lower dimension. Experimental results confirmed that the proposed method could reduce the computational cost to 85.9% /spl sim/ 53.1% compared to the previous work so as to enhance its performance obviously.

31 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023217
2022495
2021237
2020383
2019432
2018364