Post-order based routing & transport protocol for wireless sensor networks

In this paper, we propose a lightweight, application independent transport protocol for communication of the nodes belonging to a wireless sensor network (WSN) with the nodes belonging to a local area network. The framework consists of a novel downstream routing scheme and a well-known tree based upstream routing protocol for WSNs. The downstream routing protocol leverages Post-order Numbering (PN) of sensor nodes in the collection tree network formed and maintained by the upstream routing protocol. Through the proposed transport framework, using a technique similar to NATing, we achieve a seamless integration of WSNs and IP networks. The proposed protocol was not only evaluated by extensive simulations, but also implemented on a real test bed to show its practical deployability. We built our test bed around a small Wireless Distribution System (WDS) consisting of two laptop computers and eight Micaz motes attached with MTS300 sensor boards. We connected one of the computers in WDS via Ethernet to the LAN while the other operated as a server with a serial forwarder. A gateway board was attached to the second computer via a USB port which enabled it to function also as a base station for the WSN. A distinct advantage of the proposed framework is that an IP client can directly communicate with a sensor node through its base station.