In this paper, we present improved decoding algorithms for expander-based Tanner codes. We begin by developing a randomized linear-time decoding algorithm that, under the condition that
δd0>2, corrects up to
αnerrors for a Tanner code
T(G,C0), where
Gis a (
c,d,α,δ) bipartite expander with
nleft vertices, and
C0⊆F2dis a linear inner code with minimum distance
d0. This result improves upon the previous work of Cheng, Ouyang, Shangguan, and Shen (RANDOM 2024), which required
δd0>3. We further derandomize the algorithm to obtain a deterministic linear-time decoding algorithm with the same decoding radius. Our algorithm improves upon the previous deterministic algorithm of Cheng et al. by achieving a decoding radius of
αn, compared with the previous radius of
d0(1+0.5cδ)2αn. Additionally, we investigate the size-expansion trade-off introduced by the recent work of Chen, Cheng, Li, and Ouyang (IEEE TIT 2023), and use it to provide new bounds on the minimum distance of Tanner codes. Specifically, we prove that the minimum distance of a Tanner code
T(G,C0)is approximately
fδ−1(d01)αn, where
fδ(⋅)is the Size-Expansion Function. As another application, we improve the decoding radius of our decoding algorithms from
αnto approximately
fδ−1(d02)αn.