04-08-2012, 12:57 PM
Wireless technology for E-Healthcare
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1 Abstract
The wireless body area network has emerged as a new technology for e-healthcare that allows the data of a patient’s vital body parameters and movements to be collected by small wearable or implantable sensors and communicated using short-range wireless communication techniques.
WBAN has shown great potential in improving healthcare quality, and thus has found a wide range of applications from ubiquitous health monitoring and computer assisted rehabilitation to emergency medical response systems. The security and privacy protection of the data collected from a WBAN, either while stored inside the WBAN or during their transmission outside of the WBAN, is a major unsolved concern, with challenges coming from stringent resource constraints of WBAN devices, and the high demand for both security/privacy and practicality/usability.
In this article we look into two important data security issues: secure and dependable distributed data storage, and fine grained distributed data access control for sensitive and private patient medical data. We discuss various practical issues that need to be taken into account while fulfilling the security and privacy requirements. Relevant solutions in sensor networks and WBANs are surveyed, and their applicability is analyzed.
2 Introduction
Recently, with the rapid development in wearable medical sensors and wireless communication, wireless body area networks (WBANs) have emerged as a promising technique that will revolutionalize the way of seeking healthcare, which is often termed e-healthcare. Instead of being measured face-to-face, with WBANs patients’ health-related parameters can be monitored remotely, continuously, and in real time, and then processed and transferred to medical databases. This medical information is shared among and accessed by various users such as healthcare staff, researchers, government agencies, and insurance companies.
In this way healthcare processes, such as clinical diagnosis and emergency medical response, will be facilitated and expedited, thereby greatly increase the efficiency of healthcare. Based on the WBAN, a wide range of novel applications are enabled, such as ubiquitous health monitoring (UHM), computer-assisted rehabilitation, emergency medical response system (EMRS), and even promoting healthy living styles. Specifically, in UHM the WBAN frees people from visiting the hospital frequently, and eases the heavy dependence on a specialized workforce in healthcare. Thus, it is a desirable technique to quickly build cost-effective healthcare systems, especially for countries that are short of medical infrastructure and well trained staff.
In addition, in an EMRS temporary WBANs can be rapidly deployed with minimum human effort at a disaster scene so that the vital signs of injured patients can be monitored and reported to the remote health center in time, which is potentially capable of saving the lives of numerous people.
3 About the Technology
We show the general architecture of a WBAN in Fig 3. The WBAN mainly consists of tiny wireless sensor nodes that are placed in, on, or around a patient’s body. These sensors consistently monitor the patient’s vital signs, such as electrocardiogram (ECG), pulse, and blood pressure; or important environmental parameters like temperature and humidity. The sensor monitor readings, patient profile, and so on together are called patient-related data. The sensors collect and transmit the patient-related data to one or more local servers (or gateways), which may perform further data processing, aggregation, or distributed storage.
Figure 3. A general Architecture of the WBAN, which consists of tier 1 and tier 2.The collected data is either stored in the WBAN for distributed, local Access, or transferred from the WBAN to medical databases in tier3 for centralized, remote access. The users of the patient-related data of the WBAN may include patients, doctors, nurses support staff, scientists, and insurance companies.
The patient related data from all WBANs may ultimately be sent to a centralized healthcare database for permanent records. Thus, the users of patient related data can either remotely access the data from the database or query information locally from the WBAN, depending on the application scenario. related data is often stored in a distributive manner; the open and dynamic nature of the WBAN makes the data prone to being lost. Therefore, it is equally important to protect patient-related data against malicious modification and to ensure its dependability.
4 Application Scenario
Suppose Peter is injured when traveling far away from his hometown. At first, the emergency paramedic reads Peter’s implanted RFID tag to obtain his profile and medical records, and a WBAN consisting of wearable medical sensors is established and associated with Peter. Later, various healthcare workers can directly access the vital sign readings from the WBAN in real time, in order to provide better medical care. For instance, a nurse inquires on Peter’s health status from his WBAN and uploads an electronic report to the local server in Peter’s room.
Peter’s PDA has been configured with an initial access policy (AP) that controls who has access to his medical data within his WBAN. The AP automatically adapts to contexts, such as accommodating the reception staff, doctor, and nurse. Peter can also modify the AP at his own will;
For example: His sensitive AIDS record is only allowed to be shared with his nurses but not doctors.
Note that medical data is often stored and accessed distributively. Different types of monitoring data may be stored in different sensor nodes; before Peter arrives at a place with wireless Internet coverage, those data can only be stored locally in his WBAN. Direct local access to cached data in Peter’s WBAN and local servers allows freshly generated data to be viewed immediately without delay to facilitate in-time diagnosis.
Here, a natural question is how to ensure the security of the distributively stored patient-related data from its storage through transfer to access. Before we discuss the security of distributed data storage and access, we first analyze the threats faced by the distributively stored data in the WBAN.