Wireless Body Sensor Networks: Security, Privacy, and Energy Efficiency in the Era of Cloud Computing

Introduction

The field of implantable medical devices (IMDs) has witnessed a rapid proliferation and increased success in the past decade. Leveraging the technological advancements in the fields of embedded computing, processor design, and wireless radio communications, these devices are now capable of performing vital monitoring and control activities inside the human body. Most of today’s sophisticated human implantable devices, such as drug delivery systems, neurological stimulators, cardiac defibrillators, and pacemakers, are equipped with dedicated computing power resources and supported with wireless radio transmission capabilities. Such advanced computing and network communication capabilities allow these devices to deliver critical telemetric remote monitoring services in real time over the Internet. Moreover, the enormous adoption of the Cloud computing model for delivering virtualized services over the Internet has provided IMDs with lucrative processing and storage facilities that suit their data-intensive nature and analysis requirements. A recent Transparency Market Research report (Transparency Market Research, 2013) states that the IMD market in the U.S. reached a $ 25.2 billion in 2012 and were predicted to reach $ 33.6 billion by 2018. According to the same report, the IMD market is anticipated to expand at a CAGR of nearly 4% from 2012 to 2018.

This noticeable success in the field of IMDs and the major advancements in wireless sensor network algorithms and applications have stimulated the emergence of specialized biological networks termed as Body Sensor Networks (BSNs) or Body Area Networks (BANs). BSNs are specialized wireless sensor networks whose nodes are deployed on the human body either in the form of attached/embedded electrode-like patches or wearable as part of the human clothing. In both cases, BSNs consist of a collection of sensor nodes situated at strategic locations in the human body and capable of extracting and wirelessly communicating vital body signals and other context-specific environmental measurements to centralized servers in the Cloud. The centralized storage and processing resources in the Cloud provide hospitals and health care units with a reliable and timely interface to access and analyze the BSN data. Some of the vital body signals that can be monitored by a BSN are Systolic and Diastolic blood pressure, heart rate, ElectroCardioGram (ECG), ElectroMyoGram (EMG), ElectoEncephaloGram (EEG) records, breathing rate, Galvanic Skin Response(GSR), temperature, proximity, etc.

A typical BSN is presented in Figure 1. The body sensor nodes extract a predefined set of physiological body signals and wirelessly transmit the measured values in a hop-by-hop fashion to a BSN controller (usually a smart phone) attached to the human body. The BSN controller relays the collected signal values to a nearby Internet base station or router which in turn delivers the BSN physiological data to a Cloud computing infrastructure for storage and analysis. Employing BSNs in a health care environment together with the centralized storage and processing facilities provided by Cloud computing, will certainly enhance the quality of the health care service provided by supporting the ubiquitous and pervasive monitoring of the patient. With BSNs deployed on the patient’s body, medical personnel can examine and assess the patient medical conditions in real time, anywhere, and at any time without requiring the patient to be bounded to a specific location or physically connected to monitoring equipment.