A New Tree Routing Protocol for ZigBee Healthcare Monitoring Systems

摘要

ZigBee is an industrial standard for personal area network (PAN) developed for low power, cost and rate for wireless radio communications. Lately, ZigBee implementation in Healthcare Monitoring Systems (HMS) is exponentially increasing. ZigBee specification proposed that a number of wireless sensor nodes can be connected through a tree hierarchal topology in a ZigBee network. In Health sector, HMSs implement body sensor nodes that are capable of collecting human physiological data such as Heart Rate signals. However, routing in tree topology needs every sensor node to transmit data to a central node called coordinator. Parent-child is the mechanism that is used to forward packets to the coordinator in the original ZigBee Tree Routing (ZTR) scheme. However, parent-child mechanism is not suitable to transmit sensitive data such as heart rate pulses. Parent-child mechanism suffers from end to end delay problem which is a disadvantage for physiological signals as they require emergency attention. This paper is proposing a solution that attempts to solve this problem by implementing New Tree Routing Protocol (NTRP) algorithm. NTRP scheme is evaluated on NS-2 simulator tool and its simulation results show improvement of average end to end delay of 0.3-1% while the packet delivery ratio is 5-11.6%.