A survey on shortcut tree routing protocols for Zibee based wireless networks

Zigbee is a wireless networking standard which is broadly used in applications such as remote control and sensor applications. They are suited for operation in coarse radio environments and in isolated locations. In Zigbee based wireless networks, various routing protocols such as reactive routing protocols and Zigbee Tree Routing (ZTR) protocol were initially proposed. Among them, ZTR is widely used, since it neither makes use of routing table nor requires route discovery overhead and it can be used among devices that are limited in their resources. But it suffers from a serious limitation, (i.e) in ZTR the packets are routed through fundamental tree topology. Therefore, ZTR do not provide optimal routing paths. In order to surpass the limitation of ZTR, Shortcut Tree Routing (STR) protocols were proposed. These protocols find the optimal next hop node that has the smallest remaining hop counts to the destination. Hence, this paper presents a survey on various STR protocols and also compares the performance of network using STR under two cases. The first case is the one in which the nodes are static and the second is the one in which the nodes are mobile. The simulations are done using ns2 and the performance of STR is evaluated and analyzed using metrics such as average residual energy and Packet Delivery Ratio (PDR).