Localization algorithms based on hop counting for Wireless Nano-Sensor networks

Wireless Nano-Sensor networks (WNSN) consist of nanosensors equipped with nanotransceivers and nanoantennas to operate in Terahertz frequency band (0.1–10THz). Due to the peculiarities of this communication channel (such as, very short range of transmission (under lm), high interference, high path loss) and limited capabilities of nano-nodes (such as, computing, sensing, memory, energy), the existing ranging techniques designed for traditional wireless sensor networks are not longer used in the WNSNs. In this paper, two ranging algorithms based on hop-counting methods are developed to estimate the location of every nanosensor within certain area and distance between nodes in the networks. The first technique uses flooding mechanism to forward the packets to all nodes in the networks and count number of hops between two measured nodes. To overcome the problems of high overhead, duplication packets, and waste of consumption energy, the second algorithm based on clusters is developed. In this way, all sensornodes are grouped into different clusters. Cluster heads will communicate together and count the number of hops. The performance of the algorithms are analyzed in terms of estimated distance, delay by taking also account the energy constrains of nanosensors. The simulation results show that, by being aware of the limitations of nanosensors, the proposed protocols are able to support WNSNs with very high density in ranging and localizing.