Energy-Efficient Geographic Routing in 2-D Ad-hoc Wireless Networks

Geographic Routing (GR) algorithms are increasedly studied in ad-hoc wireless networks, and energy efficiency is of particular interest. Among the existing GR algorithms, the Most Forward within Radius (MFR) algorithm selects the next hop node as far as possible from the source node to minimise the network delay time while the energy consumption is not considered. The Nearest Forward Progress (NFP) algorithm selects the next hop node as near as possible from the source node to minimise the energy consumption of each hop while the total energy consumption of the transmission (summation of energy consumption of all hops) is not considered. In this paper, we propose the Optimal Range Forward (ORF) algorithm, in which the next hop node is selected based on the optimal transmission range, to minimise the total energy consumption of the transmission (summation of energy consumption of all hops) in 2-dimensional networks. Furthermore, based on ORF, we propose the Optimal Forward with Energy Balance (OFEB) algorithm, in which the next-hop node is selected not only according to the optimal transmission range but also the remaining energy of each neighbor node. In the OFEB algorithm, the total energy consumption of the transmission and the residual energy of each node are both considered to prolong the network lifetime. The network lifetime and the data received by the destination node, resulting from all the algorithms above, are compared in our simulation, and it is shown that the performance of the OFEB algorithm is significantly better than the others. Also, in this paper we introduce method for locating relay node, and derive the range of relay node locations that result in energy saving. The optimal node transmission range is derived in terms of the propagation loss factor.