scispace - formally typeset
Search or ask a question
Topic

Codebook

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


Papers
More filters
Proceedings ArticleDOI
01 Dec 2013
TL;DR: The goal of this work is the design of a low-rate limited feedback framework to improve the achievable sum-rate of the system relative to a baseline scenario where only correlation information is known at the transmitter.
Abstract: The broadcast problem with multiple antennas at the transmitter end and a single antenna at each user is studied in this work. A low-complexity transmitter architecture where linear beamforming is used to convey information to the users, and multi-user interference is treated as noise at the receiver unit of each user is considered. The vector channels that connect the transmitter to the users are assumed to be spatially correlated. The goal of this work is the design of a low-rate limited feedback framework to improve the achievable sum-rate of the system relative to a baseline scenario where only correlation information is known at the transmitter. While prior work considers either a codebook structure that is designed for spatially uncorrelated channels or for spatially correlated point-to-point systems, it is argued here that a “good” codebook design should incorporate a statistical version of the interference structure that is seen at each user. Further, instead of feeding back the codeword index that is best aligned to the user's channel vector, the index that maximizes an estimate of the signal-to-interference-and-noise ratio as perceived by the user is fed back. It is shown via numerical results that the proposed framework results in a substantial performance improvement over existing schemes across a large family of spatial correlation and across a practically relevant operating regime.

33 citations

Journal ArticleDOI
TL;DR: A new technique that uses a self-growing and self-organized neural gas network to calculate the most appropriate size of a codebook for a given database is presented, and a new soft-weighting technique, whereby each LF is classified into only one visual word (VW) with a degree of participation is proposed.
Abstract: Due to the rapid development of information technology and the continuously increasing number of available multimedia data, the task of retrieving information based on visual content has become a popular subject of scientific interest. Recent approaches adopt the bag-of-visual-words (BOVW) model to retrieve images in a semantic way. BOVW has shown remarkable performance in content-based image retrieval tasks, exhibiting better retrieval effectiveness over global and local feature (LF) representations. The performance of the BOVW approach depends strongly, however, on predicting the ideal codebook size, a difficult and database-dependent task. The contribution of this paper is threefold. First, it presents a new technique that uses a self-growing and self-organized neural gas network to calculate the most appropriate size of a codebook for a given database. Second, it proposes a new soft-weighting technique, whereby each LF is classified into only one visual word (VW) with a degree of participation. Third, by combining the information derived from the method that automatically detects the number of VWs, the soft-weighting method, and a color information extraction method from the literature, it shapes a new descriptor, called color VWs. Experimental results on two well-known benchmarking databases demonstrate that the proposed descriptor outperforms 15 contemporary descriptors and methods from the literature, in terms of both precision at K and its ability to retrieve the entire ground truth.

33 citations

Proceedings ArticleDOI
04 Aug 2002
TL;DR: In this article, a non-linear enhancement technique called audio-visual codebook dependent cepstral normalization (AVCDCN) was proposed for both audio-only and audio-Visual speech recognition.
Abstract: We introduce a non-linear enhancement technique called audio-visual codebook dependent cepstral normalization (AVCDCN) and we consider its use with both audio-only and audio-visual speech recognition. AVCDCN is inspired from CDCN, an audio-only enhancement technique that approximates the nonlinear effect of noise on speech with a piecewise constant function. Our experiments show that the use of visual information in AVCDCN allows significant performance gains over CDCN.

33 citations

Book ChapterDOI
10 Nov 2010
TL;DR: A new method based on the firefly algorithm to construct the codebook of vector quantization is proposed, which gets higher quality than those generated from the LBG and PSO-LBG algorithms, but there are not significantly different to the HBMO- LBG algorithm.
Abstract: The vector quantization (VQ) was a powerful technique in the applications of digital image compression. The traditionally widely used method such as the Linde-Buzo-Gray (LBG) algorithm always generated local optimal codebook. This paper proposed a new method based on the firefly algorithm to construct the codebook of vector quantization. The proposed method uses LBG method as the initial of firefly algorithm to develop the VQ algorithm. This method is called FF-LBG algorithm. The FF-LBG algorithm is compared with the other three methods that are LBG, PSO-LBG and HBMO-LBG algorithms. Experimental results showed that the computation of this proposed FF-LBG algorithm is faster than the PSO-LBG, and the HBMO-LBG algorithms. Furthermore, the reconstructured images get higher quality than those generated from the LBG and PSO-LBG algorithms, but there are not significantly different to the HBMO-LBG algorithm.

33 citations

Journal ArticleDOI
TL;DR: A novel codebook construction design based on CUR-decomposition technique to reduce the dimensionality problem in channel correlation matrix (rotation matrix) is proposed and can be applied in the fifth generation massive antenna multi-user system with over a hundred antenna elements.
Abstract: Millimeter wave (mm-Wave) communications are emerging to meet the increasing demand for high transmission data rate in high user density areas. Meanwhile, the mm-Wave base station (BS) needs to employ a large number of antenna elements to increase the gain as well as serve a huge number of users. However, a vast number of antenna elements causes dimensionality problem in channel correlation matrix (rotation matrix). Therefore, we propose a novel codebook construction design based on CUR-decomposition technique to reduce the dimensionality problem. In this paper, the original correlation matrix is decomposed to the product of three low dimension matrices ( $\mathbf {C}$ , $\mathbf {U}$ , and $\mathbf {R}$ ). The new rotated codebook is then constructed by the new rotation matrix. Moreover, we evaluate the new decomposition matrix with the original matrix in terms of compression ratio and mismatch error. We also provide the achievable sum rate capacities for singular value decomposition, zero forcing, and a matched filter techniques to compare with the proposed method. Furthermore, the system capacity enhancement related to the number of antenna elements and the required feedback bits are analyzed. Simulation results show that the proposed method achieves much better system performance since the dimensionality problem is solved. The proposed method can be applied in the fifth generation massive antenna multi-user system with over a hundred antenna elements.

33 citations


Network Information
Related Topics (5)
Feature extraction
111.8K papers, 2.1M citations
88% related
Wireless network
122.5K papers, 2.1M citations
88% related
Network packet
159.7K papers, 2.2M citations
87% related
Wireless
133.4K papers, 1.9M citations
87% related
Wireless sensor network
142K papers, 2.4M citations
86% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023217
2022495
2021237
2020383
2019432
2018364