Performance Evaluation of Wearable Sensor Systems: A Case Study in Moderate-Scale Deployment in Hospital Environment

A wearable sensor system enables continuous and remote health monitoring and is widely considered as the next generation of healthcare technology. The performance, the packet error rate (PER) in particular, of a wearable sensor system may deteriorate due to a number of factors, particularly the interference from the other wearable sensor systems in the vicinity. We systematically evaluate the performance of the wearable sensor system in terms of PER in the presence of such interference in this paper. The factors that affect the performance of the wearable sensor system, such as density, traffic load, and transmission power in a realistic moderate-scale deployment case in hospital are all considered. Simulation results show that with 20% duty cycle, only 68.5% of data transmission can achieve the targeted reliability requirement (PER is less than 0.05) even in the off-peak period in hospital. We then suggest some interference mitigation schemes based on the performance evaluation results in the case study

Adaptive MAC Protocol Design for Energy Efficient and Reliable WBAN Link

The present need for a well-organised and continuous health care service at an affordable price gives rise to a wireless health monitoring technology. Wireless body area network is an emerging field of a wireless sensor network that works in the vicinity of the human body. This technology has its most significant application in the modern healthcare system. This wban architecture is designed to get the health information and daily routine of human activity (both physical and psychological) through energy efficient and reliable radio transceivers connectivity these modern devices behave according to some predesigned rules called communication protocols. The mac protocols are designed specially according to wban standards and requirements. The physiological sensors installed in wban system consume a large amount of energy for communication that leads to frequent data interruption and also a change of implanted devices. As this is troublesome for both patient and server, protocols are continuously upgraded to make the communication highly energy efficient and reliable. The prime aim of this work is to reduce the energy consumption and increase the lifespan of the network. This work proposes an energy harvesting adaptive mac protocol applied for node connectivity and detailed simulation study carried out with the proposed protocol proves to be having minimum power consumption, increased network lifetime, and high throughput compared to the existing mac protocols in wban framework. We have used hybrid mesh topology where all nodes have both uplink and downlink. Here we are utilizing a gts based multi-hop technique and adaptive wake-up mechanism for the sleep mode of the transceiver to minimize the wake-up periods

Challenges in body area networks for healthcare: The MAC

Body area wireless sensor networks (BANs) are a key component to the ubiquitous healthcare revolution and perhaps one of its most challenging elements from a communications standpoint. The unique characteristics of the wireless channel, coupled with the need for extreme energy efficiency in many healthcare applications, require novel solutions in medium access control protocols. We present the main characteristics and challenges associated with BANs from a healthcare perspective, and present some MAC techniques based on studies of the BAN channel that could be used to address these challenges

Adaptive parameters adjustment in WBAN to mitigate Wi-Fi interferences

Wireless Body Area Network (WBAN), called also Wireless Body Sensor Network (WBSN), is composed of a set of tiny wireless devices (sensors) attached, implanted or ingested into the body. It offers real time and ubiquitous applications thanks to the small form, the lightness, and the wireless interface of sensors. WBAN performance is expected to be considerably degraded in the presence of Wi-Fi networks. Their operating channels overlap in the 2.4 GHz Industrial Scientific and Medical (ISM) band which produces interference when they transmit data, accompanied by data losses and quick battery exhaustion. Therefore, it is crucial to mitigate the interference between WBAN and Wi-Fi networks in order to maintain the efficiency and the reliability of the WBAN system. Proposals in the literature use an added complex hardware in WBAN system, or perform the exchange of additional information, or establish expensive communications, or affect the quality of service of the WBAN. Unlike previous researches, we proposed simple, low cost and dynamic method that adaptively adjusts specific parameters in the Medium Access Control (MAC) layer. We have proved the effectiveness of our approach based on theoretical analysis and simulation using MiXiM framework of OMNet++ simulato

HACMAC: A reliable human activity-based medium access control for implantable body sensor networks

Chronic care is an eminent application of implantable body sensor networks (IBSN). Performing physical activities such as walking, running, and sitting is unavoidable during the long-term monitoring of chronic-care patients. These physical activities cripple the radio frequency (RF) signal between the implanted sensor nodes. This is because various body postures shadow the RF signal. Although shadowing itself may be short, a prolonged activity will significantly increase the effect of the RF-shadowing. This effect dampens the communication between implantable sensor nodes and hence increases the chance of missing life-critical data. To overcome this problem, in this paper we propose a link quality-aware medium access control (MAC) protocol called HACMAC, which adapts the access mechanism during different human activities based on the wireless link-quality. Our simulation results show that compared with the access mechanism suggested by the IEEE 802.15.6 standard, the reliability of the wireless communication is increased using HACMAC even while transmitting at a strongly low transmission power of 25µW effective isotropic radiated power (EIRP) set by the IEEE 802.15.6 standar