Body Sensors And Medical Healthcare

Published Date: 02 Nov 2017

Abstract

Body Area Networks (BANs) play an important role in mobile health monitoring such as, monitoring the health of patients in a hospital or physical status of soldiers in a battlefield. In more common terms, a Body Area Network is a system of devices in close proximity to a person’s body that cooperate for the benefit of the user. This paper will give a little introduction about the Body Area Network (BAN). In this paper also, it will describe the system architecture that involved and also the applications that use this BANs. In addition, it discusses the challenges and standards associated with this BANs. At the end of this paper, I will briefly discuss the issues associated with BANs and some solutions that are on the horizon.

Keywords: Body Area Networks, Body Sensor Networks, Sensor Networks, Personal Area Networks, Healthcare Applications, IEEE 802.15

Introduction

Body Area Network (BAN), sometimes referred as smart-clothing, is a network of wirelessly connected sensors placed on or around the human body. This wearable sensor network can be used for health monitoring. These sensors which are placed on the human body measure the physiological parameters such as heartbeat, body temperature, motion etc. The sensors collect data from the body and send it to a base station for processing and storage, usually through a wireless multi-hop network. Then the base station sends data to the medical server via internet as shown in Figure 1. Since BANs work on physiological values which are quite sensitive information, providing security to the inter-sensor communication within a BAN is extremely important. BANs are used to monitor hospital patients in an automated pervasive monitoring environment. Ubiquitous computing and monitoring enable the doctors to predict, diagnose, and react to situations efficiently. BANs can also play a significant role in assisted living for elderly patients. BANs set up in the patient’s home will allow earlier detection of any variation in the patient’s physiological condition. BANs have the potential to develop a personalized healthcare system where only monitoring, detection and diagnosis of the patients are performed.

Since sensors are tiny devices, their battery power is an issue and the changing of batteries frequently is quite problematic. Since BAN deals with the human body and its physiological values, securing the communication among sensors is just like securing the human life. Securing the inter-sensor communication in a BAN requires the distribution of encryption/decryption keys. This kind of solution requires initial network setup time and also the overhead of the change if made in the BAN’s topology. A mechanism for EKG-based key agreement in a BAN is provided in that uses fast Fourier transform (FFT) for feature extraction. The authors use EKG signals as physiological values for generating the common keys for secure inter-sensor communication. The technique consumes a lot of power and its commitment phase is also not so secure because of the exchange of blocks in this phase.

This paper presents an improved EKG-based key agreement scheme that uses discrete wavelet transform (DWT) for feature extraction. The advantage of using DWT over FFT is that its computational cost is linear whereas the computational cost of FFT is linearithmic. The scheme has another advantage over the existing schemes; that is, it uses watermaking during the commitment phase in order to make the system more secure. The proposed scheme fulfils the requirements described in for a secure system, the keys should be long, random and time variant. The security is improved and its plug and play capability remains intact, the sensors are just put on the human body and they start secure communication with one another.

The rest of the paper organized as follows: Section 2 presents the related work and section 3 describes the system model. Section 4 explains the key agreement scheme in detail. Section 5 discusses the security analysis. In section 6, the performance results are shown followed by section 7 which conclude the paper.

Applications

Body sensors and medical healthcare

These applications are typically associated with the low data rate needed to communicate vital data about humans such as heart rate, ECG (Electrocardiogram) and EEG (Electroencephalography) data, blood pressure, body temperature, levels of certain chemicals such as oxygen and medications in the blood, motion, etc. The use cases to consider include a hospital environment as well as outdoor and home environment. In the outdoor patient and home environments the basic topology is the same as in a hospital environment except that the bedside monitor is replaced by either a data collection device or a gateway to a central data base implemented for example by a cellular phone. In either case the application aims at supporting people in managing their medical condition without putting overly restrictive limitations on their mobility.

Artificial organs and implants control and monitoring

These are artificial organs, that has to be moved like limbs and their movement has to be controlled by manual controllers, thoughts or external devices. Other cases include internal artificial organs that have to be mainly monitored. Implants and self-moving capsules that has in-body missions has to be controlled and may have the possibility to transmit their data collected.

Monitoring of persons operating in harsh environment

Persons that may be exposed to harsh conditions of operation, such as emergency forces have to be monitored to be protected. This may include fire department forces.

Personal fitness monitoring

In a fitness monitoring application the person exercising is not only interested in listening to the music, but also in collecting and displaying data relevant to the exercise. Heart rate sensors have been introduced many years ago and have been widely accepted. Additional sensors can be added as needed to support a meaningful exercise; they would provide information about speed, body temperature, oxygen level, location information and other relevant data.

Personal audio systems

This application scenario is centered on a personal music player device. A wireless headset is connected to the player and as soon as a second audio source is added to the network and dynamically switching between sound sources may be performed.

Mobile communication devices

The addition of a mobile communication device offers the option to exchange information between devices within the local body area network and the outside world. The communication standard used to connect to the outside world depends on the specific implementation of the gateway function in the mobile device and could use cellular, wireless LAN or other wireless technologies.

In this application scenario the mobile communication device would normally be the central point connecting to all other terminals in its local body area network, which could include sensors, wireless headsets, personal storage devices, PDA, a hands-free car environment, and others. With such a network topology it will be possible to offer wide range connectivity to local devices even if they need to consume only very little power.

Video communications

The total network load associated with a video related use case depends on the specific scenario. In its simplest form there will be a single video stream coming from the camera sensor going to a personal recording device or a display. The system may include connection to other devices or home media server.

Peripheral devices

In order to complement the functionality of body area network peripheral devices may be needed as devices in the network. Examples include remote control units, printers, authentication and identification devices, scanners, etc. Some of these functions can be integrated with other devices already present in the network. However, the network needs to be designed such that the desired functionality is still maintained even if this device is removed from the network, e.g. in case of an empty battery.

System architecture

The target of a BAN which is medical monitoring system is to acquire, process, store, and visualize a number of physiological parameters in an unobtrusive way such as simultaneous acquisition of EEG/ECG/EMG bio potential signals.

Typical deployment configurations shown in and are given in Figure 3. The top configuration on the left is optimized for maximum battery life. Individual sensors communicate only with the personal server (PS) in a WBAN. The PS communicates with the Home Server (HS) using Wireless WLAN. A HS is typically already connected to the Internet. This configuration is also applicable for inpatient monitoring. Ambulatory monitoring requires the direct connection of a PS to the Internet (WAN connectivity), as illustrated in the center configuration. Finally, a modification of the first configuration may be excluding the PS to reduce the system price, as shown in the bottom depiction, but this is likely to increase total power consumption. The different configurations can exploit different parts of the price/power/performance design space.

Issues / challenges

The design wireless BAN systems for continuous ambulatory monitoring and may other medical and non-medical applications raises a number of challenging issues that include:

For system:

Need for extremely low power operation, low weight, and small size

Sensor flexibility necessary to adapt to the user’s state and changes in the environment

Seamless connectivity necessary for sensor integration into the monitoring system

System awareness of environmental and patient factors associated with the use of wearable sensors in normal living conditions

Effective audio or visual user interfaces on the personal server

Minimization of health hazard due to radiation

For communication:

Secure, private and reliable communication and data storage

Reliable transmission of important data

Fault tolerant system operation

Standards for wireless communication, messaging and system support

For the sensors:

Further sensor size reduction and ruggedization

Development of power efficient on-sensor signal processing algorithms and technological advances will eventually allow energy scavenging from the environment

Seamless customization, configuration, and integration of sensors into a WBAN, and automatic uploads to support intermittent links to the medical server

IEEE standards

IEEE Standards are used around the world to help industries and companies open business opportunities, maximize research efforts, generate public and customer trust, build order in the marketplace and enhance safety. The IEEE Standards Association (IEEE-SA) is a leading developer of industry standards in a broad-range of industries. Globally recognized, the IEEE-SA has strategic relationships with the IEC, ISO and the ITU and satisfies all SDO requirements set by the World Trade Organization, offering more paths to international standardization.

The purpose of the IEEE802.15.6 standard is to provide an international standard for a short range, low power and highly reliable wireless communication for use in close proximity to, or inside, a human body.

Conclusion

Hopefully this paper introduced the reader to the BAN technology. I discussed the development of BAN and how it grew into the more general concept of BAN. I then introduced the system architecture of the BAN concept. BAN systems that monitor vital signs promise ubiquitous, yet affordable health monitoring. I believe that BAN systems will allow a dramatic shift in the way people think about and manage their health—in the same fashion the Internet has changed the way people communicate to each other and search for information. This shift toward more proactive preventive healthcare will not only improve the quality of life, but will also reduce healthcare costs. The proliferation of wireless devices and recent advances in miniature sensors prove the technical feasibility of a ubiquitous health monitoring system. However, BAN designers face a number of challenges in an effort to improve user’s compliance that depends on the ease of use, size, reliability, and security.