Satisfying the Restricted Isometry Property with the Optimal Number of Rows and Slightly Less Randomness
Shravas Rao
TL;DR
This paper addresses constructing RIP matrices with the optimal row count while minimizing randomness. It introduces a generalized Hanson-Wright bound for $\varepsilon$-biased, almost $\ell$-wise independent distributions and uses it to show that a matrix $\Phi$ drawn from such a distribution yields $Q = O(k \log(N/k))$ rows and only $O(k\log(k)\log(N/k))$ random bits. The approach leverages a Johnson-Lindenstrauss-type projection framework to bound quadratic forms $\|\Phi x\|_2^2$ for all $k$-sparse $x$. The result improves randomness efficiency among optimal-row RIP constructions and advances deterministic/rand-bit-efficient designs in compressed sensing.
Abstract
A matrix $Φ\in \mathbb{R}^{Q \times N}$ satisfies the restricted isometry property if $\|Φx\|_2^2$ is approximately equal to $\|x\|_2^2$ for all $k$-sparse vectors $x$. We give a construction of RIP matrices with the optimal $Q = O(k \log(N/k))$ rows using $O(k\log(N/k)\log(k))$ bits of randomness. The main technical ingredient is an extension of the Hanson-Wright inequality to $ε$-biased distributions.
