We propose a simple method to constructing step mask and corresponding wavelet functions that generate tight frames on the field Qp of p-adic numbers. To construct this we use three new ideas. First, consider only an additive group Qp. Second, special tree. Thirdly, do not principle unitary extension, Pontryagin's duality instead. Using method, obtain all refinable functions.

Non-orthogonal communication is a promising technique for future wireless networks (e.g., 6G and Wi-Fi 7). In the vector channel model, designing efficient non-orthogonal schemes amounts to following extremum problem: \[ \max \min_k \frac{|v_k|^2}{\sigma^2 + \sum_{l \neq k} \langle v_k, v_l \rangle^2} \] where maximum taken among systems $(v_k)_1^N \subset \mathbb{R}^d$ satisfying $c_1 \leq |v_...