On the perspective transformation for efficient relay placement in wireless multicast networks

This letter investigates the relay placement problem in wireless multicast networks consisting of multiple sources, relays, and destinations. The data transmission from the sources to the destinations is carried out via the relays employing physical-layer network coding technique. Hybrid automatic repeat request protocol with incremental redundancy is applied for reliable communication. In particular, considering a general setting of nodes in irregularly shaped network, an efficient relay placement algorithm is proposed based on perspective transformation technique to find optimal relay positions for minimizing either the total energy consumption or the total delay in the whole network. The proposed algorithm not only helps reduce the relay searching complexity but also facilitates the relay placement for optimizing networks of any shape