The Body Area Networks

Published Date: 02 Nov 2017

Abstract: The field of computer literacy is improving consistently day by day letting to process large data sets while maintaining levels of connectivity. Meanwhile the advancement in miniaturization allows for connectivity and miniaturization. Body Area Networks (BANs) can be identified as a combination of connectivity and miniaturization. Formally BAN means a system of devices called nodes which are either set up close to the human body or around human body. In last few decades, there was a huge improvement in electronical devices. As a matter of fact a type of those devices, called sensors were developed and minimized in physical size. So those sensors are used to set up a BAN to attain benefits for human beings. Mainly these systems are beneficial in medicine. Even though BANs has a very short history, there are a lot of researches done and will be explained the core of them here. The technologies of BANs, applications of BAN and threats will be described through this paper. As a conclusion it can be quoted that BANs will play a major role in the world of low power networking in the near future.

1. Introduction

There is a new trend among people to monitor their own physiology. This was done for monitoring specially for sport activities in the past but today it has been changed and it is used even in controlling their own diseases and even for military activities. In the past it was not that easy to have body checkups frequently and be aware of the condition of the body. With the vast improvements of the technology these circumstances are reduced. With the rapid advancements of technology devices and sensors are becoming smaller. So those sensors can be used to build an entire wireless networks inside the human body. Doctors, trainers and gamers use these new technologies to attach sensors in or near human body so that those systems can be used to monitor the human body easily. In medicine, these kinds of systems can be used to get internal information of human body easily. When the traditional methods are applied to get the required result, doctors may obtain wrong results since in hospitals data may be collected in a short time period but in a system like BAN, data will be collected during a large time. A longer period monitoring will be more beneficial in athletics. BANs are used to monitor the stamina of the athletes so that their level of sugar, water and oxygen levels can be adjusted according to the results [1]. Also some researches provide the advancements in BAN in military operations, which BSN would transmit the details to databases where decisions for troops’ movements can be achieved. In military and for automotive purposes also BANs are used. As a classification of BAN, these are can be divided into three main categories such as Intra-BAN, Inter-BAN and Beyond-BAN systems. BANs have incorporated with other wireless technologies such as radio frequency identification (RFID) technology [2], Zigbee [3], Bluetooth, Bluetooth low energy [4], video surveillance systems, wireless personal area networks, wireless local area networks, internet and cellular networks. There are a lot of researches done focusing on Body Area Networks, however there are so many improvements that have to be done in this area. Still there are some researches going on to create more flexible and more user friendly Body Area Networks applications. BANs are introduced mainly in medical field so that I decided to take this area since I am a student who has done biology and I am highly motivated for studying this area and I think I can do something new to this area since I have the technological background also. And also I have planned to come up with suggestions to overcome the drawbacks and limitations of BANs.

First section of this paper gave a brief introduction about Body Area Networks. Second section provides the overview of the research area and its importance. Section 3 provides the information about major researches of this area. Section 4 is about applications of Body Area Networks where Section 5 describes about the new areas of Body Area Networks. Section 6 describes about the discussion area of the study.

2. Overview – Body Area Networks

A Body Area Network (BAN) is a wireless network. Initially these are known as wireless personal area networks. BAN is usually formed by sensors which have the qualities of lightweight, small-size, ultra-low-power, interoperable and intelligent wearable. Those sensors are placed on the body surface, around it or implanted inside the human body. The development of BANs is brought forward many applications such as medical patient monitoring, recreational gaming control, military activities and athletic body monitoring. The range of BAN devices can vary in terms of bandwidth and power consumption. There is another one which goes with BANs, Body Sensor Networks (BSN). Body Area Network is a subset of Body Sensor Networks. There are some common scenarios for BANs such as Body Sensor Networks, sports monitoring systems, mobile device integration and personal video devices.

Figure 1: A Body Area Network

As the first step of constructing a Body Area Network, nodes or electronic sensors have to be placed on the human body or around it. Those have to be placed in a particular order which all the nodes can be communicated with each other and at last all those have to obey a central location, most probably near heart of human body. So a special node will be placed around heart as to act as the main location where all the nodes are communicated each other. This can also be identified as a Wireless Personal Area Network though it is actually a Body Area Network. Then we have to build up a special network where to get the connection between the Body Area Network and personal network. This personal network can be identified as a personal server where it will be connected to internet through either using GPRS or Bluetooth technologies. Then the ultimate servers can be connected as the last step and do the necessary mechanisms. For the connection of BAN and Personal Network, special network called Zigbee is used. This is a mesh network and the radio standard is IEEE 802.15.4 [5].

2.1 Categories of BANs

BANs can be categorized into three tiers such as Intra-BAN communication, Inter-BAN communication and Beyond-BAN communication. Intra-BAN communication means the radio communication between two nodes. These two nodes can be either two sensors or one sensor and a portable device like mobile phone or a dedicated personal server. Inter-BAN communication involves more devices to the environment such as access points, mobile phones and computers. Infrastructure based architecture is the most common among current BAN systems. Limited spaces can be used to fulfill the need efficiently. In Beyond-BAN, it requires a device to connect Inter-BAN to external network. This device can be either a mobile smartphone or dedicated device. Using an uninterrupted link, there can be achieved several advantages such as the ability of monitoring a patient’s recent history alongside with the current situation. This will be helpful for the personnel in an emergency situation [6].

Figure 2: Three tier architecture based on BAN

2.2 Technologies in BANs

There are various technologies which are used for BANs. Some of them are wearable technologies, node authentication, Zigbee, radio-frequency and wireless-network technology. Wearable BAN (WBAN) is playing an important role to get the real time and accurate data with limited energy consumption. Wearable BAN is created by applying a number of wireless nodes embedded on the human body, which provides the live data to user by monitoring the different notations. Mainly this technology is useful in military and aerospace systems. Node authentication is another very important technology in BANs. A critical issue in BANs is how to protect the integrity and privacy of a person's medical data over wireless environments in a resource efficient manner. The improved Jules Sudan algorithm is proposed to set up the key agreement for the BAN authentication [7]. BAN is based on the use of Zigbee standard technology and off-the-shelf modules. Zigbee has less power consumption, lesser cost and high density of sensors per network, simple protocol, and global implementation [3]. There some more special technologies apart from the earlier explained technologies such as ANT, Rubee, RFID, Sensium, Zarlink, Insteon and Z-Wave [8].

2.3 Algorithms used in BANs

Node authentication is a very important section in Body Area Networks. The improved Jules Sudan algorithm is the key algorithm in Body Area Networks authentication. This algorithm is proposed to get the agreements for the message authentication in Body Area Networks. This agreement can secure the data communication over Body Area Networks without any distribution overheads. Also the algorithm helps for the power consumption in the scenarios. Also there are some low-energy scheduling algorithms which are used in BANs. Comparing with similar technologies, BANs require only 1mW/Mbps power consumption and can vary between 1mW-100mW. In BAN based wearable faint fall detection system, BAN-based full impact detection algorithm is used. This is an example for using algorithms for energy consumption.

Figure 3: BAN-based wearable detection system

With the assumption of having embedded processors in BAN systems with dynamic voltage or frequency, critical-path based low–energy scheduling algorithms are developed. Some of those algorithms are Directed acyclic graph (DAG), Initial tightest schedule and development of a new DAG graph, Critical-path identification, Static scheduling algorithm and Dynamic scheduling algorithm [9]. These scheduling algorithms are written in C++ programming language.

2.4 Key researches and Applications

There are plenty of researches done regarding Body Area Networks. As a result of those some researches, in year 2005, a very impressive health application called HealthGear [10] was launched. Some more researches were done to monitor the health and physical of humans. Code Blue is one of them, done in Harvard University in 2005. SMART is another project done in Arizona, USA 2008, which was developed to monitor the psychological signals of patients [8]. Some researches have done based on the usage of BAN systems in military and sports training. As results of those, there is a trend of integrating unobtrusive devices for sports and fitness. One of the applications for them is Nike + IPod sports kit [8]. Also some experiments have done for the usage of BANs in military operations as well. Those are converted into application and use for the making of positioning soldiers in the battlefield.

3. Major Researches in Body Area Networks

There are a lot of important researches done and going on regarding the applications of BAN and the usage of BAN. Since this is important in medical, sports, military and automotive, there are some important researches can be found. One of them is a survey done on this area by Erik Karulf, which focused more on several uses in BAN technologies, more usages for the medical section, technologies surrounding BANs and common applications in BAN [5]. As the applications in healthcare which are described in this research, they emphasized more on the integration of Body Sensor Networks (BSNs) over BANs and the importance of BSNs as well. Also it tells that the need of a traditional antenna for this kind of network is not that important since human body can act as a channel for the limited range communication. In 2003, two special researches from University of Twente published focusing on the area of continuous monitoring of vital constants for mobile users [5]. There are more researches done on the specific areas of BANs as follows.

Figure 4: Typical modules in a sensor node

3.1 Node Authentication

Node authentication is another very important technology in BANs. A critical issue in BANs is how to protect the integrity and privacy of a person's medical data over wireless environments in a resource efficient manner. The improved Jules Sudan algorithm is proposed to set up the key agreement for the BAN authentication. It is very much important of functioning the sensor authentication. The proposed Jules Sudan key agreement can secure the data communications over BANs in a plug and play manner without any key distribution overheads [7]. Research done by Lu Shi et al. introduced two different authentication mechanisms as crypto-graphic and non-cryptographic authentication mechanisms. They introduced a light-weight crypto-based authentication schemes which are so important for the improvement of the node sensor authentication in BANs [11]. In those non-cryptographic authentications, those can be divided into categories such as biometric-based authentication, channel-based authentication and proximity-based authentication. As per the research, channel-based authentication can be sub divided into some as software-based, hardware-based and location-based. Talking about proximity-based authentication, Rasmussen and Capkun introduced the initial design of Radio Frequency (RF) for the usage of wireless channels [8].

3.2 Energy Consumption

BANs applications vary form the usage of power from 1mW to 100mW. Comparing to similar technologies, BANs energy consumption is very low. For attaining this low power consumption, several low power Media Access Protocols have been used. There some main MAC protocols which are presented in various researches. Cascading Information retrieval by Controlling Access with Distributed slot Assignment (CICADA) is one of those MAC protocols, which was done research - A low-delay protocol for multihop wireless body area networks by Latr B et al. in 2007, which was designed for wireless multihop and mobile based Body Area Networks. With the implementation, it synchronizes the duty cycles of sensors with power requirement variations. BAN MAC is also another one, dedicated MAC protocol which enhances power consumption in BAN systems. This protocol is compatible with IEEE 802.15.4, which is the same use for Body Sensor Networks. These BAN-MAC protocols adjust dynamically to achieve the best power consumption according with the node sensors in the particular Body Area Network [8].

3.3 Radio Technologies

These technologies are detailed described in the first parts of this paper so that this section only reveals the researches which were done based on those radio technologies in BANs. Nokia has done some researches and introduced Bluetooth low energy technology in 2004, which is used mostly in BAN applications. These are highly used in BANs which are configured as star topologies, which provide better mobility support. Also there are some more researches which based on some other radio technologies such as Zigbee [5].

3.4 Medical and Military operations

There are a lot of researches on the usage of BANs in medical applications. In year 2005, a very impressive product, HealthGear, was launched. HealthGear is a wearable real-time monitoring device consisting with set of sensors connected via Bluetooth to a Bluetooth-enabled cell phone. This equipment can monitor and analyze the user's blood oxygen level and heart rate [10]. Code Blue is the other device, which is somewhat similar to HealthGear but more advance. Shnayder V et al. addressed on this product as a research, Sensor networks for medical care in Harvard University 2005. Based on the drawbacks of Code Blue and HealthGear, more researches were done and as a result of it Gao T et al. came up with a research, the advanced health and disaster aid network, and implemented a scheme target application called AID-N [8]. Jiang S et al. came up with another research on medical applications in BAN called CareNet, an integrated wireless sensor networking environment for remote healthcare. In the usage of BANs in military operations also some key researches were done. In military operations there are some roles which have to be taken into account. Ensuring that adequate water is delivered and consumed, reducing the likelihood of body harm to harsh environments and improving the quality of medical care in an injury [8].

3.5 Sport trainings

BAN applications are widely spread out while in different sports also BANs are integrated. For that, a lot of researches were done in a way that gets the identification of how to use environment integrating with BAN services. It has been identified through some of those researches that in order to identifying specific postures, node sensors have to be placed on the particular sections in the human body [8]. So that using this knowledge players can avoid the injuries due to wrong and incorrect postures in to some extent. A special research was done by Arvind DK et al., The speckled golfer in 2008 targeting the golf players. There the target audience was golf players and coaches monitor the players’ performance, movements and strokes. Using the sensory data which were taken by the sensors attached to the golf players body, coaches identified easily the mistakes of the players made and could directly provide feedbacks for them. Also these sensory data could be collected for a long time and based on those past data, coachers may come up with good conclusions about the players’ performance within next few years. All these were done based on that research.

4. Applications of Body Area Networks

Applications of BAN can be divided into sections as medical BANs applications, military BANs applications and sports BANs applications.

4.1 Medical BANs applications

Involvement of BAN systems to medical application is one of the key factors of reducing the illnesses and physical disable of human. There are some new and good applications were introduced in past decades where the combination of this network is the core section of those applications.

4.1.1 Code Blue

In this application, several different types of node sensors are individually connected with a Zigbee enabled transmitters so that those will be directly connected with access points in the mesh network. But there isn’t any sign of an intra-BAN communication of the sensors in this product so that there will be communication between more than one access points. There patients’ sensors publish the information and physicians can subscribe to the existing network through multicasting. Using this subscribing mechanism, physicians can get the specified information they need and the body signal types that is essential to be collected.

Figure 5: Nodes in Code Blue

4.1.2 AID-N

This supports both intra-BAN and Inter-BAN communication mechanisms in this environment. Mainly this application targets of dealing with mass casualty situations. Though the steps of constructing the core are very similar to Code Blue but still there is a main difference. Instead of the usage of access points, here special wireless repeaters are attached on the wall along a predefined emergency path. When access point indicates green, both patients and medical staff can identify the correct emergency path. Due to get the medical requirement special Global Positioning System is attached with the product to continue the outdoor services as well.

4.1.3 SMART

A research revealed that patients’ mental condition will be got down rapidly when he or she is an emergency room for some purposes. SMART was developed to monitor the mental reactions while the patients’ are waiting in a room of an emergency department. The ultimate goal was using the product to identify what were the causes for this and the amount of the deduction in the mental condition. Peoples’ lives cannot be put into a risk because of the poor attention in an emergency room. SMART device can gather the required data from human body and send wirelessly to the central server where the data is stored and by doing the calculations and other essential operations, an alert will be sent to the patient. So depending on the alert message, patient can do the necessary preventions before his mental condition get into a worse.

4.2 Military and Sports applications

The global trend of integrating unobtrusive devices with the sports and fitness equipments and also with military tools is a trend in the global market today. Considering these applications, those are integrated with peoples’ smart phones and wrist watches. Since these equipments are very much familiar for human in their day to day activities, usage of those applications and devices are very much easy. One of the good applications is Nike + iPad sports kit where it connects Nike shoes and Apple iPad devices together to build up a BAN system. When athletics do their trainings those nodes which are attached to the shoes, will collect the data and send to the server. Using those outputs, players can increase their efficiency and trainers can get necessary actions to train their players according to the output. Not only that, even web services can be integrated with those applications so that there will be more functional BAN based applications in military and sports areas [8]. Integrating sensors into the soldiers’ body will help in the battlefields. By using those sensor data, military officials can get necessary actions on where to put the soldiers by avoiding the mines on the battlefield.

5. New areas of Body Area Networks

Though Body Area Network applications are mainly covered the areas of medical, sports and military there are still new good emerging applications which are depended on BANs in different fields. One of the fields is automotive field. In there with the rapid development of automotive vehicle technologies, the BAN systems are also integrated for the fast improvement of the existing field. Those can be called as BAN based intelligent systems. In those systems also we can find the same BANs implementation, which the network of sensor nodes are around of the particular driver of the vehicle and using the inputs such as expressions on the face, whether yawning or not, head movements and raising eye brows driver can get the output alert of the BAN system. Those alerts can be used to improve the driving style of the driver if it’s bad and learn to use the road effectively [8]. Also some researches have discovered that not only facial and body expressions of the driver but also the heart beating rate and even pulse rate can be used to determine better results through the BANs applications in such automotive systems. Some new researches have pointed out that not only BANs systems can use getting the medical information but also a well-developed BAN system can also be used to identify the facial emotions of normal people and using BAN systems the heart beating rate, pulse rate and also respiration rate of human can be achieved. So these are some of the new areas of BANs and since this is an emerging technology, more advancement will come near future.

6. Discussion

There is a new trend among people to monitor their own physiology. With the rapid advancements of technology devices and sensors are becoming smaller. So those sensors can be used to build an entire wireless networks inside the human body. Doctors, trainers and gamers use these new technologies to attach sensors in or near human body. These sections which communicate to make sense and act in a coordinated way build up a Body Area Network (BAN). BANs have incorporated with other wireless technologies such as radio frequency identification (RFID) technology, Zigbee, Bluetooth, Bluetooth low energy, video surveillance systems, wireless personal area networks, wireless local area networks, internet and cellular networks. Mostly this is used in medical areas but it is also used in military services as short range person-to-person communications that could help protect front line soldiers and this can be also used to identify a particular person in a particular domain. BANs can also be used in athletics. There are similar technologies to BANs such as Body Sensor Networks (BSN), Wireless Personal Area Networks but still BANs is special in its’ power consumption and frequency range. There are special algorithms in BANs systems such as Jules Sudan algorithm and various other power consumption algorithms which were explained above. Also there are a lot of applications which were developed for the betterment of medicine, military, sports and automotive domains. Although there is much improvement still there are some constraints and bottlenecks in these systems. There are still more communication and services issues which have to be solved. Also there are some social issues regarding with these systems. These networks are dealing with central servers and distributed databases so that security of those servers and data optimizations and data mining mechanisms should have to be handled in an efficient way. As the next step I hope to capture those areas, identify the issues and present ideas to resolve them.

Acknowledgement

I would like to extend my deepest and sincere gratitude to Mr. Shalinda Adikari for the guidance and support given to me during the Independent Study as the supervisor.