Wireless Sensor Network technology has emerged as a key infrastructure for the development of facilities like Crisis Management System and health monitoring of critical patients. The rising need of telemedicine and e-health technology in Pakistan is being resulted in development of required infrastructure based on WSN technology. This research work addresses the designing and implementation of emergency medical care based on Mesh Architecture of Wireless Sensor Network of Multiple nodes. An infrastructure to support real time medical care taking advantage of WSN architecture is being developed by prototyping an NCU (Neo-natal Care Unit). The same infrastructure may also serve as an effective Crisis Management System and health monitoring of critical patients. The prime objective is to obtain information from health sensors e.g. in ambulance and transmit the same to main Control room through a wireless communication system. This kind of medical help system is developed by utilizing license free ISM Band (Industrial Scientific Medical Band) at an operating frequency of 2.4GHZ. This research project also involves design of Radio Frequency Modem for exchanging the wireless data among the various hospitals and vehicle. The proposed system follows the master slave configuration based on TDM technique to establish the communication path which enables a hospital or any ambulance within the service area to communicate the master to access any slave.
Keywords: Wireless Sensor Network, Crisis Management System, Mesh Architecture, ISM Band, Radio Frequency Modem, Master slave configuration, TDM technique
I. Introduction
Researchers in computer, networking, and medical fields are working to make the broad vision of smart healthcare possible. Most focus is upon development of WSNs for medical applications in disasters i.e. in case of emergency conditions. The situation calls for creating a WSN based project for emergency medical help. We have come up with a project to develop infrastructure which would support real time medical care taking advantage of WSN architecture.
Wireless sensor networks are significantly different from traditional wireless networks such as wireless local area network (WLAN), mobile ad-hoc network (MANET), or cellular networks. In these networks, the tasks of organization, routing and mobility management are used to optimize quality of service (QoS) and heighten bandwidth efficiency. As an example of wireless sensor networks importance, Intel® Proactive Health believes that wireless sensor networks may be “crucial to address the pending global age wave and public health crisisâ€. Wireless sensor networks can be effectively used in healthcare to enhance the quality of life provided for the patients and also the quality of healthcare services. The development of wireless sensor networks was motivated by military applications such as battlefield surveillance. They are now used in many industrial and civilian application areas, including industrial process monitoring and control, machine health monitoring, environment and habitat monitoring, healthcare applications, home automation, and traffic control.
Basic_Architecture
Fig 1: Working of WSN nodes [Reference]
Unique characteristics of a WSN include:
Limited power they can harvest or store
Ability to withstand harsh environmental conditions
Ability to cope with node failures
Mobility of nodes
Dynamic network topology
Communication failures
Heterogeneity of nodes
Large scale of deployment
Unattended operation
Node capacity is scalable, only limited by bandwidth of gateway node.
II. System Design Platform
A Wireless sensor networks consists of many spatially distributed autonomous devices, called smart sensor nodes that cooperatively monitor environmental or physical conditions at different locations.
(a) Sensor Node
A sensor node, is a node in a wireless sensor network that is capable of performing some processing, gathering sensory information and communicating with other connected nodes in the network. The typical architecture of the sensor node is shown in figure 2.1.
Fig.2: sensor node [Reference]
In addition to one or more sensors, each node in a sensor network is typically equipped with a radio transceiver or other wireless communications device, a small microcontroller, and an energy source, usually a battery. A sensor node might vary in size from that of a shoebox down to the size of a grain of dust,[1] although functioning "motes" of genuine microscopic dimensions have yet to be created. The cost of sensor nodes is similarly variable, ranging from hundreds of dollars to a few pennies, depending on the size of the sensor network and the complexity required of individual sensor nodes. Size and cost constraints on sensor nodes result in corresponding constraints on resources such as energy, memory, computational speed and bandwidth. A sensor network normally constitutes a wireless ad-hoc network, meaning that each sensor supports a multi-hop routing algorithm (several nodes may forward data packets to the base station). In computer science and telecommunications, wireless sensor networks are an active research area with numerous workshops and conferences arranged each year.
The applications for WSNs are varied, typically involving some kind of monitoring, tracking, or controlling. Specific applications include habitat monitoring, object tracking, nuclear reactor control, fire detection, and traffic monitoring. In a typical application, a WSN is scattered in a region where it is meant to collect data through its sensor nodes.
III Implementation of Wireless Sensor Network for Medical Care
The implementation phase will address the designing and implementation of emergency medical care based on Mesh Architecture of Wireless Sensor Network. It would focus to provide recovery in the following scenario. The task is to design and implement the complete hardware and software system to communicate with fixed locations (hospitals) in real time scenario to access data in full duplex mode as well as from mobile ambulances within a vicinity of 30 KM while sitting at a master site. Medical professionals can obtain not only patient records, but real-time vital signs and other reference data at the patient bedside without relying on reams of paper charts and physical paper handling.
The whole system architecture is distributed sensor system over nodes and can be easily understand after viewing the block diagrams.
Fig. 3: Block diagram of node 1
Fig. 4: Block diagram of node 2
Reference to block diagrams of node 1 and node 2, the NCU temperature is kept maintained using a preset value. If temperature rises, either automatic fan will start for forced cooling or ventilator roof will be opened for natural cooling. The light intensity will be controlled as per requirement. The level of Drip or blood transmission will be monitored by using level sensor. The analog values (Temp, Light, and Level) will be converted into digital through ADC and after necessary conditioning will be fed into micro-controller. The automated roof system is comprised of stepper motor and will be opened/closed as per need. On node 2, the provision of interfacing external device is available and will be used accordingly.
