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arXiv 2202.09605cs.ITastro-ph.IMgr-qcmath-phmath.ITmath.MGmath.MP
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关于最佳格量化器

On the best lattice quantizers

Erik Agrell, Bruce Allen

AI总结:

本文推广Zamir-Feder白色量化误差定理至局部最优格及其最优乘积,推导NSM上界,并构造多个维度中改进的格量化器。

摘要:

格量化器用取自特定离散格的向量来逼近任意实值源向量。量化误差是源向量与格向量之间的差。在1996年的一篇经典论文中,Zamir和Feder证明,全局最优格量化器(即使均方误差最小的量化器)具有白色量化误差:对于均匀分布的源,误差的协方差是单位矩阵乘以一个正实数因子。我们推广了这一定理,证明同样的性质成立于:(i)任何其均方误差无法通过对生成矩阵进行微小扰动而降低的格;以及(ii)由本身在(i)意义下局部最优的格构成的最优格乘积。我们通过证明对乘积格生成矩阵的任何下三角或上三角修改都会降低归一化二阶矩(NSM),得出了任意维度下最优格NSM的上界。利用这些工具,并采用当前已知的最佳格量化器来构建乘积格,我们在13至15维、17至23维以及25至48维中构造了改进的格量化器。在某些维度中,这些是首批被报道的归一化二阶矩低于此前已知最佳上界的格。

英文摘要:

A lattice quantizer approximates an arbitrary real-valued source vector with a vector taken from a specific discrete lattice. The quantization error is the difference between the source vector and the lattice vector. In a classic 1996 paper, Zamir and Feder show that the globally optimal lattice quantizer (which minimizes the mean square error) has white quantization error: for a uniformly distributed source, the covariance of the error is the identity matrix, multiplied by a positive real factor. We generalize the theorem, showing that the same property holds (i) for any lattice whose mean square error cannot be decreased by a small perturbation of the generator matrix, and (ii) for an optimal product of lattices that are themselves locally optimal in the sense of (i). We derive an upper bound on the normalized second moment (NSM) of the optimal lattice in any dimension, by proving that any lower- or upper-triangular modification to the generator matrix of a product lattice reduces the NSM. Using these tools and employing the best currently known lattice quantizers to build product lattices, we construct improved lattice quantizers in dimensions 13 to 15, 17 to 23, and 25 to 48. In some dimensions, these are the first reported lattices with normalized second moments below the best known upper bound.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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