Abstract
For providing the reliable and effective wireless transmission in a relay-assisted network coding system, we propose Vandermonde Coding (VC), a novel network coding scheme with little overhead for both source and relay. VC uses the feature of Vandermonde matrix for guaranteeing linearly independent coding coefficient set. Comparing to random network coding (RNC), which needs extra overhead to record the coding coefficient, VC has little overhead because the generating index of Vandermonde matrix can be related to other information in the packet, like sequence number. For comparison purpose, we propose a theoretically optimal but yet impractical scheme—Max matching, using the idea from graph theory. In our simulation, VC performs equally to Max matching. But the existing popular coding schemes at relay, such as forwarding, RNC and XOR, do not perform well. To our surprise, XOR coding scheme will produce self-redundant packet, which contains coding coefficient that is linearly dependent with the set composed by the packets the relay sent. Although VC has great performance, it increases the computing complexity at relay. Thus, we also propose a lightweight coding scheme, XOR Fibo, which is a novel modification of XOR coding scheme. To avoid generating self-redundant packets, XOR Fibo XORs a subset of received packets, according to the Fibonacci sequence. In our simulation, XOR Fibo has a performance close to VC.