Bidirectional Piggybacking Design for Systematic Nodes With Sub-Packetization l=2
Ke Wang · IEEE Communications Letters · 2025
In this work, we propose an explicit bidirectional piggybacking design (BPD) for systematic nodes with subpacketizationl= 2 and field sizeq=O(n⌊r/2⌋+1), wherer = n − kequals the redundancy of an (n, k) linear code. This BPD focuses on the codes with a repair degree ofd = k+ 1 and handles the repair of parity nodes naively. Compared with previous piggybacking designs, BPD has lower average repair bandwidth forl= 2 andr≥ 3. Moreover, we prove that BPD can be given over a field Fqwithq≤ 256 whenn≤ 15 andr≤ 4. For instance, the proposed BPD based on the (14, 10) Reed-Solomon (RS) code can be given over F28, which achieves approximately 41% savings in the average repair bandwidth for systematic nodes over the naive repair approach. This is the lowest repair bandwidth achieved so far for (14, 10)256RS codes withl= 2. Specially, ifr− 1 ≥ ⌈k/2⌉, our BPD has the optimal repair bandwidth for systematic nodes.