Relaying Packets in a Two-tiered Wireless Network Using Binary Integer Programming

Relay transmissions improve performance and save communication energy in wireless network. We present an optimal relay nodes assignment algorithm to maximize the number of information packets received at the sink for a two-tiered wireless network, in which the relay nodes are temporarily placed and have energy constraint. We first derive the optimal transmit power theory from relay node to sink node. Provided the limited energy at the relay nodes, we prove that the total transmission periods or the relay network lifetime is fixed. Subsequently, we determine the optimal dynamic association between edge nodes and relay nodes (multiple-to-one mapping) using binary integer programming (BIP). Experimental results show that the proposed method has significantly better performance than two other schemes in terms of the total number of information packets received at the sink. Combined with the optimal relay transmit power technique, the two-tiered wireless network can achieve the highest capacity considering the energy constraint of relay nodes.