Codebook

About: Codebook is a research topic. Over the lifetime, 8492 publications have been published within this topic receiving 115995 citations.

Toward A Discriminative Codebook: Codeword Selection across Multi-resolution

Abstract: In patch-based object recognition, there are two important issues on the codebook generation: (I) resolution: a coarse codebook lacks sufficient discriminative power, and an over-fine one is sensitive to noise; (2) codeword selection: non-discriminative codewords not only increase the codebook size, but also can hurt the recognition performance. To achieve a discriminative codebook for better recognition, this paper argues that these two issues are strongly related and should be solved as a whole. In this paper, a multi-resolution codebook is first designed via hierarchical clustering. With a reasonable size, it includes all of the codewords which cross a large number of resolution levels. More importantly, it forms a diverse candidate codeword set that is critical to codeword selection. A Boosting feature selection approach is modified to select the discriminative codewords from this multi-resolution code-book. By doing so, the obtained codebook is composed of the most discriminative codewords culled from different levels of resolution. Experimental study demonstrates the better recognition performance attained by this codebook.

Hierarchical Codebook-Based Multiuser Beam Training for Millimeter Wave Massive MIMO

Abstract: In this article, multiuser beam training based on hierarchical codebook for millimeter wave massive multi-input multi-output is investigated, where the base station (BS) simultaneously performs beam training with multiple user equipments (UEs). For the UEs, an alternative minimization method with a closed-form expression (AMCF) is proposed to design the hierarchical codebook under the constant modulus constraint. To speed up the convergence of the AMCF, an initialization method based on Zadoff-Chu sequence is proposed. For the BS, a simultaneous multiuser beam training scheme based on an adaptively designed hierarchical codebook is proposed, where the codewords in the current layer of the codebook are designed according to the beam training results of the previous layer. The codewords at the BS are designed with multiple mainlobes, each covering a spatial region for one or more UEs. Simulation results verify the effectiveness of the proposed hierarchical codebook design schemes and show that the proposed multiuser beam training scheme can approach the performance of the beam sweeping but with significantly reduced beam training overhead.

Vector quantization over a noisy channel using soft decision decoding

Abstract: A soft decision decoder is presented. The soft decision decoder is optimal in the mean square sense, if the encoder entropy is full. A source vector estimate is obtained as a linear mapping of a soft Hadamard column. The soft Hadamard column is formed as a generally nonlinear mapping of soft information bits. It is shown that the best index assignment, on the encoder, is obtained in the special case of a linear mapping from the soft information bits. Simulations indicate that the jointly trained system performs better than channel optimized VQ with hard decisions. The interesting case, for applications, of using an ordinary VQ codebook as encoder, together with our soft decision decoder, is also investigated. In our examples this approach gives comparable performance to channel optimized VQ with hard decisions. >

Signal conditioned minimum error rate training for continuous speech recognition

Abstract: Hierarchical signal bias removal (HSBR) signal conditioning (26) uses a codebook (28) constructed from the set of recognition models (34). HSBR signal conditioning and recognition model training may be based on the same set of recognition model parameters and provides a reduction in recognition errors.

Method and apparatus for encoding or decoding data in accordance with an NB/(N+1)B block code, and method for determining such a block code

Abstract: A method and apparatus for encoding or decoding data in accordance with an NB/(N+1)B block code, and a method for determining codebooks for use in such encoding or decoding. Some such methods select positive and negative codebooks that are complements of each other, including by eliminating all candidate code words having negative disparity and filtering the remaining candidate code words in automated fashion based on predetermined spectral properties to select a subset of the candidate code words as the code words of the positive codebook. Preferably, all but a small subset of the (N+1)-bit code words (determined by a primary mapping) can be decoded by simple logic circuitry, and the remaining code words (determined by a secondary mapping) can be decoded by other logic circuitry or table lookup.