History Of The Body Area Networks

Abstract

In the recent few years there is tremendous advancement especially in the field of integration circuit, small sensors and in the wireless networks.in body area networks (BANs) these devices considerably suitable for integrating in any scenario like health monitoring , in sport, and even in military prospective due to its considerable light weight , low power, and sensing capability. BANs provide cheap, reliable, and scalable system for monitoring daily activities for short to long period of time. But still there are a number of challenges issues like integration of devices, system designing according to the user scenario, security and privacy of the data, modification and social issues must be resolved in order for BANs to become ubiquitous. In our report we discus BANs background, its applications, and relationship.

Introduction

BANs (Body Area Networks) is a combination of micro and advanced Nano technology components for to improve the speed and accuracy of data recording. Generally BANs consist of small but sensitive sensors and actuators for monitoring and log data, then data sent to base station for storage. Users can access to this data in base station via internet or by other mean. BANs are actually a modern invention and primarily design for health industry (doctor and other staff) to monitor the health status. By taking the benefit of this technology we can monitor much more closely patients with chronic diseases like, asthma and diabetes. Doctor update the patients record quickly and efficiently to store general information of patients health.

In United States and other part of Europe, they made different pilot programs to monitoring patient’s health status. They introduced bracelet with chips and antennas that can used to follow the patient position. They attached antennas on patient cloths to track him in the hospital and it send alert when he begins to collapse. A company is currently working on a project Healthy Aims [1] which focused on body devices that helps millions of people. Body Area Networks take low power radio frequencies (RF) and transfer the data of patients in real time. Doctors are able to monitor and change the setting for specific deployed devices on the body to improve the performance devices as well patient health. Pacemaker devices was produce 1960’s have to endure pain and stress of surgery because it setup as a part of the body and send the patient health situation to RF transceiver, where it send directly to the doctor. This time interval always up to date the doctor about patient. By BANs Doctor and his staff can access to patient record at any time so they don’t need to visit the patient or patient don’t need to visit the clinic, it is a good method in prospective of save time and money by visiting the clinic many time during the month or weeks.

BANs is extremely compact and may be complex by its design, but as the sensor devices are very unassertive and a patient will be able to live a normal life. All sensors have same controlable mechanism like same element, power supply, and wireless transceivers. But they are design in such method that they can self-govern for the entire life [2]. They are designed for the measurement of temperature, movement, and location. Sensor and actuator implanted inside the body and they interact wirelessly each other’s in BANs and process data is transmitted from implanted devices to external devices. Mechanism of a actuator is like environmental agent. In BANs the data passes through sensor to sensor then sent to it base station where it can be transmitted to recipient via internet.

2 Body Area Networks History

History about the body area network is not so old to go back many years to find out some material about BANs, taking advantages of some tiny useful technology in this sense is a new and unique idea. A number of different groups was work on PAN(personal area network) in Massachusett Institute of technology and that later grew out of the work on 1990’s. The group actually wanted to get the information by interconnect different appliance on the body and to measure the position of the body by using electric field sensor. The main head for developing Personal Area Networks was Thomas G. Zimmerman. He introduces the new technology that allows the body to act like conductor. There was another name Neil Gershenfeld in that field who was in the Massachusett Institute of technology, incharged of the Media and Physics group. He and his group applied a method near -field coupling to solve the problem of determine the accurate position and its relationship with other parts, by fixing pairs of antennas on body part for example elbow and hand, and then run an electric current through them. They learned that as one move the capacitance of the circuit was charged. So they determine the exact position of the antennas after measuring the capacitance.

There was a problem in the measurement method that the measurement was no longer accurate if hand was placed between the antennas but it was solved by the Zimmerman. There was actually another group working in the Media lab asked them to develop a network such that all electric gadgets that a person can carry are connected together.

Many people carried digital devices around thereself but no one communicate to other.For example a person who has a mobile phone, a pager, a PDA or a digital watch mean all about his person at the same time. They both Zimmerman and Gershenfeld learned that, they can represent 1 or 0s, if they modulated the electric field which flowing through a person body,and allowing the body to carry digital information. At the end they discovered that if they used frequency and power that kept very low then the signal will not propagate far beyond the body. It mean that if devices could detect the signal on the body. This used of current at very low or small amount was unnoticed by anyone before.

2.1 Body Area Network Applications

There are many possible application for communication like in the hospital, in patients monitoring system at home (post-operative care), use in a large scale throughout the world. There is also a list of BANs usages in various field like in sport, military, mesh, and in sport fields.

Body Area Network Sports Applications

In the present sporting arena many different readings are possible to take without having an athlete on a treadmill in a laboratory. It provide the platform to measure various levels during different competition in real life, for example in race, where coaches, need his pi athlete’s strengths and weaknesses.

Body Area Mesh Network Applications

The body area network consist of low-power and very reliable sensor networking. The low power usage allows longer life Batteries of motes or Gateways. The mesh network provides high reliability and long range communication. Mesh Networking is much more reliable and much capable of data sending

Body Area Network Medical Applications

Body Area Networks (BANs) can be used to provide interfaces for diagnostics purposes, in the hospital they used for administration of drugs, aid rehabilitation, and for remotely monitoring human physiological data. And for future prospective in hospital or at home it is used for monitoring the patient continuously and give required medication. So by this way patient need no more in the hospital with connected machines for monitoring.

Body Area Network Military Applications

Body Area Network has done a tremendous job in the military. So many of the military applications that we can use includes, their locations, health monitoring, their temperature and hydration levels, also very useful to enhance the strength, and many more factors for military prospective.

2.2 Body Area Network Devices

2.2.1 Body Area Network Sensors

With rapid improvements in medical research, more and more health sensors have been developed to assist caregivers in monitoring their patients’ conditions. These sensors have been getting smaller, making it possible for the sensors to be worn or to be implanted into the human body.

2.2.2 Body Area Network Actuators

The most significant products by any company would be the actuators. we can express an actuator as a device that transforms or converts energy into motion. Also applied as a force, an actuator usually is a mechanical apparatus that takes energy, normally constructed by liquid, air, or electricity, and converts that into a specific kind of motion. This particular product that would help build effective engineering designs in a safe and efficient manner and easily implemented anywhere according to the requirement. [3]

2.2.3 Body Area Network Devices usages

Two main non-computer devices (sensors and actuators) can be used in BANs network. The main function of sensors are to measure human body parameters like temperature, electrocardiogram, heart beats rates and the pressure on the joints, These can be taken insidly or outsidely of the human body. Whereas Actuators have some particular action like to get the information received by the sensors and do work on instruction given by web or PDA. They are as following

For monitoring muscle activity we can use an EMG (electromyography) sensor .

For monitoring brain electrical activity we can use An EEG (electroencephalography) sensor.

For monitoring trunk position we can use tilt sensor (TS).

For monitoring respiration we can use breathing sensors.

For monitoring heart activity we can use ECG (electrocardiogram) sensor.

A sensor for blood pressure.

To estimate a users’ activity we used movement sensors (MS).

Description: http://www.sintef.no/upload/BAN.jpg

Fig 2: A BAN on an Athlete :

http://www.sintef.no/home/Information-and-Communication-Technology-ICT/Instrumentation/Biomedical-Instrumentation/Body-Area-Networks/

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2.3 Body Area Networking

Before implementing the Body Area Network, a number of networking issues need to be solved. In this interferences when a node sends data (after processing) directly to central devices there is direct communication that might causes unnecessary rises of temperature in the tissues, there is another way data is sent through intermediate nodes to the destination by multihop communication. The data might pass to other nodes to the way to PDA if node attached to foot, that mean that at the same time the number of data pathways night exist in the same tissues. Node are like routers but it eliminate internal interference and more energy efficient. In PANs communication IEEE 802.15 standard used which basically sure that all group devices in the design of BANs should work with all togather.

2.4 Body Area Network Software

UC Berkley in California is developed “Tiny OS (Operating System)” which is an open sourse operating system in used wireless embedded sensor network.OS is extremely small in sense of memory and code writing which make it suitable for sensor network where they use minimum memory. The search is going on by using this tiny OS in sensor networks to measure some extra ordinary work . For examples sensor networks that are used to monitor volcanic eruptions and tracking/tracing (for help purposes) of fire fighters in buildings. There is a another option available that is toolkit of MSR network embedded sensors that allow user to perform different actions like process the data, collect data, and also visualise data from sensor network. The search is still going on so let us see which development OS or MSR come fist but till yet both available for free download.

3. Challenges of Body Area Networks (BANs)

Body Area Networks (BANs) consists of tiny sensor that actually placed around the body (attached on the skin or on the cloths), which take power from attached battery or from body. In BANs all the nodes communicate collectively to the central node (PDA) or other devices which are connected to the internet so data pass through to a particular person or to a particular application.

There are a numbers of challenges still in BANs networks which must be overcome by engineer, they are as following:

Power sources of life timer needs to be increased in the sensors networks (SN), or adopt different methods to get energy from other sources like body heat so it also should be perfected.

The interaction of the different sensors or nodes and the main node like PDA, that should be designed in such a way that it allow some specialist applications to be written to perform particular functions for example disease management.

The device needs to be intelligence in sense of memory and processing capabilities for processing, storing and transferring the data.

To give a full and clear picture of human physiology, Sensor need to be integrated Physically, Chemically, and Biologically and the BAN components integrated for reliable and cost effective way.

3. Body Area Network User Cases

. Body Area Networks (BANs) technology actually develop biomedical engineering according to the natural byproduct of existing sensors. Actually this technology is suitable for any scenario by its low bound of power and bandwidthHowever,there are many potential to use BAN technology due to its flexibility that is as following,

Body Sensor Networks (BSNs)

Integration of different mobile devices

Different personal video devices (VD)

Audio system of wireless (WS).

Monitoring system for sport and fitness.

Each case have unique requirement in term of bandwidth, power usage, signal distance and for latency. These cases use IEEE 802.15 standard which is use for different working group in wireless personal area networks (WPANs). So they think to use this standard within different devices for inside and around the body.And later they develop the standard for BANs and introduces a long range of possible devices to support this standard. For power balance and data rate the task group gave applications and appropriate devices for development. The figure below describe the comparison between power load and data rate in BANs.

Fig (1) comparison between data rate and power.[1]

In the above picture as we can see the range of different devices which can be used in BANs in comparison of power consumption and data rate. The table below also give us a full picture of devices that conform to work in a similar set of requirement, according to the demand of user case, yet still encompass a wide range and variety of devices

Network setup time

< 1 sec

(Per device setup time excludes network initialization)

Network Density

2 – 4 nets / m2

Startup Time

< 100 us or

< 10% of Tx slot

Power Consumption

~1 mW / Mbps

Network Size

Max: 100 devices / network

Latency (end to end)

10 ms

Distance

2 m standard

5 m special use

Effective sleep modes

Operation in global, license-exempt band

Effective sleep modes

Peer to Peer, and Point to Multi-point communication

Future proof

Upgradeable, scaleable, backwards compatible

Quality of Service &

Guaranteed Bandwidth

Latency (end to end)

[1] http://www1.cse.wustl.edu/~jain/cse574-08/ftp/ban/index.html

6. Zigbee wireless sensor technology

ZigBee is the specification of a low-cost, low-power wireless communications solution design to fulfil the needs and requirement of our architecture. ZigBee is of high level Communication protocols using small, low power digital radios bases on the IEEE 802.15.4 standard for wireless personal area Networks (WPANs). The Zigbee protocol standard contains the specifications of the network layer (NWK) and application layer (APL). Inside the application layer, functions are defined separately as the application support sub-layer (APS), the Zigbee device objects (ZDO), the Zigbee device profile (ZDP), the application framework (AF), and Zigbee security services. The comparisons of ISO OSI, TCP/IP, and ZigBee/802.15.4 are shown in the fig below:

Fig 6.1.1 Zigbee with OSI Layers.

Zigbee builds upon the physical layer and medium access control defined in IEEE standard 802.15.4 (2003 version) for low-rate WPAN’s. The specification goes on to complete the standard by adding four main components: network layer, application layer, Zigbee device objects (ZDO’s) and manufacturer-defined application objects which allow for customization and favor total integration.

Besides adding two high-level network layers to the underlying structure, the most significant improvement is the introduction of Zigbee device objects (ZDO’s). These are responsible for a number of tasks, which include keeping of device roles, management of requests to join the architecture network, device discovery and security.

Fig 6.1.2 Zigbee stack.

4. System Capability Requirements

The characteristics of sensor networks and requirements of different applications have a vital role on the network design objectives in terms of network capabilities and network performance. The main design objectives for sensor networks include the following several aspects.

Small Node Size:- Reducing node size is one of the primary design objectives of sensor networks. Reducing node size can facilitate node deployment, and also reduce the cost and power consumption of sensor nodes.

Low Node Cost:- Reducing node cost is another primary design objective of sensor networks. It is important to reduce the cost of sensor nodes so that the cost of the whole network is reduced.

Low Power Consumption:-Power is a major role in any System prospective. Reducing power consumption is the most important objective in the design of a sensor network. Since sensor nodes are powered by battery and it is often very difficult to change their batteries, it is crucial to reduce the power consumption of sensor nodes so that the lifetime of the sensor nodes, as well as the whole network is prolonged.

Self – Healing:-In sensor networks, sensor nodes are usually deployed in a region of interest without careful planning and engineering. Once deployed, sensor nodes should be able to autonomously organize themselves into a communication network and reconfigure their connectivity in the event of topology changes and node failures.

Scalability:-In sensor networks, the number of sensor nodes may be on the order of tens, hundreds, or thousands. Thus, network protocols designed for sensor networks should be scalable to different network sizes.

Adaptability:-In sensor networks, a node may fail, join, or move. This result changes in node density and network topology. Thus, network protocols designed for sensor networks should be adaptive to such density and topology changes.

Reliability:-For many sensor network applications, it is required that data be reliably delivered over wireless channels. To meet this requirement, network protocols designed for sensor networks must provide error control and correction mechanisms to ensure reliable data delivery.

Fault Tolerance:-Sensor nodes should be fault tolerant and have the abilities of self – testing, self – calibrating, self -repairing, and self – recovering.

Security:- Sensor nodes are deployed in a hostile environment and thus are vulnerable to adversaries. In such situations, a sensor network should introduce effective security mechanisms to prevent the data information in the network or a sensor node from unauthorized access or malicious attacks.

5. Research Pappers.

A number of major operations on Mobilehealth are being conducting all over the world especially in European countries like Sweden, Germany, Spain, and Netherland. It is used to monitor a limited range of condition in patient outside the hospital by the medical personnel.

Germany:

Telemonitoring of patients with cardiac arrhythmia.

The Netherlands:

Integrated homecare for women with high-risk pregnancies, Tele trauma team.

Spain:

Support of home based healthcare services, Outdoor patient rehabilitation.

Sweden:

Lighthouse alarm and locator trial, Physical activity and impediments to activity for women with RA, Monitoring the vital parameters in patients with respiratory insuffiency, Homecare and remote consultation for recently released patients in a rural area.

[3] http://www.mobihealth.org/

But a number of different issues arose as a result of these trials like handover, operator errors, data rate fluctuation, and the most common issue of power supplies insufficient. There are also some other issues like privacy and security (For instance, will the data that is being transferred remain private or is it secure), control and legal issues (may someone send false information to the network ) regarding BANs. If someone tell it to perform some dangerous function like make a patient warm or overdose, or is this legal to inform someone like companies that are interesting about its work weather he/she has weak heart or having any kind of disease in advanced BANs. Lastly some imported functions are operated and controlled by the computer that can be damage or stop working at any stage and the actuators that regulated the flow of certain chemical in the body stop then who is responsible, so these issues need to be address before BANs applied in the daily life routine.