Construction A Lattice Design Based on the Truncated Union Bound
Jiajie Xue, Brian M. Kurkoski, Emanuele Viterbo
TL;DR
The paper addresses finite‑dimensional Construction A lattice design at $n=128$ by optimizing binary component codes using a truncated union bound derived from a truncated theta series. It selects the component code $\mathcal{C}$ to minimize the required $\text{VNR}$ for a target word error rate $P_e$, and demonstrates results with EBCH and polar codes showing a new best known lattice at $P_e=10^{-5}$ using $(128,106,8)$ EBCH, as well as strong performance from polar‑code lattices (e.g., $(128,99,8)$). The approach provides analytic design guidance with lower decoding complexity than Construction D, validated for $P_e\le 10^{-4}$ and extendable to higher dimensions and other binary codes; the work highlights practical near‑ML performance for medium‑dimensional lattice codes and its potential impact on compact, low‑latency communications.
Abstract
This paper considers $n= 128$ dimensional construction A lattice design, using binary codes with known minimum Hamming distance and codeword multiplicity, the number of minimum weight codeword. A truncated theta series of the lattice is explicitly given to obtain the truncated union bound to estimate the word error rate under maximum likelihood decoding. The best component code is selected by minimizing the required volume-to-noise ratio (VNR) for a target word error rate $P_e$. The estimate becomes accurate for $P_e \leq 10^{-4}$, and design examples are given with the best extended BCH codes and polar codes for $P_e= 10^{-4}$ to $10^{-8}$. A lower error rate is achieved compared to that by the classic balanced distance rule and the equal error probability rule. The $(128, 106, 8)$ EBCH code gives the best-known $n=128$ construction A lattice at $P_e= 10^{-5}$.
