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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: In this paper, a new class of distributed differential space-time codes for wireless relay networks that use codebooks consisting of scaled unitary matrices is proposed, and the conditions involving the relay matrices and the codebook that need to be satisfied are identified.
Abstract: The differential encoding/decoding setup introduced by Kiran et al, Oggier-Hassibi and Jing-Jafarkhani for wireless relay networks that use codebooks consisting of unitary matrices is extended to allow codebooks consisting of scaled unitary matrices. For such codebooks to be usable in the Jing-Hassibi protocol for cooperative diversity, the conditions involving the relay matrices and the codebook that need to be satisfied are identified. Using the algebraic framework of extended Clifford algebras, a new class of Distributed Differential Space-Time Codes satisfying these conditions for power of two number of relays and also achieving full cooperative diversity with a low complexity sub-optimal receiver is proposed. Simulation results indicate that the proposed codes outperform both the cyclic codes as well as the circulant codes. Furthermore, these codes can also be applied as Differential Space-Time codes for noncoherent communication in classical point to point multiple antenna systems.
32 citations
Patent•
13 Aug 2015TL;DR: In this article, a method for data transmission by a device in a communication system includes modulating a first data stream using a codebook to produce a second data stream, wherein the codebook is in correspondence with a multi-dimensional modulation map that includes a number of distinct projections per complex dimension that is smaller than a small number of modulation points of the multidimensional modulation map.
Abstract: A method for data transmission by a device in a communication system includes modulating a first data stream using a codebook to produce a second data stream, wherein the codebook is in correspondence with a multi-dimensional modulation map that includes a number of distinct projections per complex dimension that is smaller than a number of modulation points of the multi-dimensional modulation map, and transmitting the second data stream over allocated resources in the communication system.
32 citations
TL;DR: This paper proposes a novel approach to language identification for documents containing mixture of handwritten and machine printed text using image descriptors constructed from a codebook of shape features, which is easily extensible and does not require skew correction, scale normalization, or segmentation.
32 citations
TL;DR: This correspondence proposes a dual-function hybrid beamforming architecture, where the antenna array is split into sub-arrays that are separated by a sufficiently large distance so that each sub-array experiences independent fading, and shows that the architecture attains the dual-functions of beamforming and diversity.
Abstract: In this correspondence, we propose a dual-function hybrid beamforming architecture, where the antenna array is split into sub-arrays that are separated by a sufficiently large distance so that each sub-array experiences independent fading. The proposed architecture attains the dual-functions of beamforming and diversity. We then demonstrate that splitting the array into two sub-arrays provides the best performance in terms of the achievable rate as a benefit of the diversity gain obtained in addition to the beamforming gain. However, the performance starts depleting if the array is partitioned into more than two sub-arrays because of diminishing additional diversity gains, which fails to compensate for the beamforming gain erosion due to splitting the antenna arrays. Additionally, we analyze the so-called discrete Fourier transform-mutually unbiased bases (DFT-MUB) aided codebook invoked for the conceived design, which imposes an appealingly low complexity. Explicitly, we show that for the proposed dual-function sub-array-connected design, the DFT-MUB assisted codebook outperforms the state-of-the-art precoding benchmarks and performs close to the optimal precoding matrix.
32 citations
TL;DR: A modified version of the original algorithm is introduced, which identifies a large number of codebooks having minimum average distortion, under the constraint that, in each step, only modes having no descendents are removed from the tree.
Abstract: A pruning algorithm of P.A. Chou et al. (1989) for designing optimal tree structures identifies only those codebooks which lie on the convex hull of the original codebook's operational distortion rate function. The authors introduce a modified version of the original algorithm, which identifies a large number of codebooks having minimum average distortion, under the constraint that, in each step, only modes having no descendents are removed from the tree. All codebooks generated by the original algorithm are also generated by this algorithm. The new algorithm generates a much larger number of codebooks in the middle- and low-rate regions. The additional codebooks permit operation near the codebook's operational distortion rate function without time sharing by choosing from the increased number of available bit rates. Despite the statistical mismatch which occurs when coding data outside the training sequence, these pruned codebooks retain their performance advantage over full search vector quantizers (VQs) for a large range of rates. >
32 citations