Evaluation of Body Area Networks

Body Area Network, due to recent advances in wearable sensors, intelligent surveillance with small size and low weight are made in low power consumption. Human physiological activities are constantly monitored by sensors. In this article, key controversies surrounding the field of BAN communications, including layers, and for example, the patient's health status and patterns of movement and etc.


Introduction
BAN-Body Area Network is composed of three layers, which include Intra-BAN communication, Inter-BAN communication, and Beyond-BAN communication.Body sensor with advances in circuit design, signal have progressed.MAC layer parameters are named as well as technologies and projects.Overall, this network is used for the patient's health status and patterns of movement and sports, and so on.

Communication of Architecture BAN
Wireless networking technology that available on WLANs are differences with BANs as follows: Figure 1.describes a general architecture of a health monitoring system is based on the BAN.ECG, EEG, EMG, motion sensors and blood pressure sensors that their data on a PS-personal server sends adjacent.Then, via Bluetooth or WLANs, the data is sent to faraway places of a physician to determine the immediate in a real-time.History in the database for storing medical or similar equipment to send emergency alerts.In this article, BAN communications architecture is divided into three components:  Covering the range of several components that are described that at low levels and high levels indicate and facilitating the creation because of these components, BAN efficient systems for a wide range of applications.Each component is designed to formalize.

First layer: Intra-BAN Communication
For the introduction of the Intra-BAN communication in reference to radio communications, about two meters around the human body, which is also divided into the following categories.As seen in figure 1, (1) there are communications between sensors and body, (2) there are communications between personal devices, body sensors, and (PS) Portable (eg Mobile PDA, etc) that have a direct communication.
Body sensors and network BAN, design communication within the Intra-BAN communication, which are very sensitive.Furthermore, battery failure itself, and features low bit rate sensor in the device body issues are challenging for designing a MAC protocol capable of efficiently providing a QoS-quality of service.In this issue, we avoid the challenges of connecting wireless sensors and personal devices plans which are available.
As MITHril (the books encompass health -wearable medical technology page 42 to 49) (Pentland A, 2004)

Second Layer: Inter-BAN Communication
WSNs cannot be separated and they are commonly worked as the rotating system, BAN rarely works alone.The price we establish a connection between PS and define one or more AP.Access profound spread on the part of the infrastructure or in a strategic location in dynamic environments are address to the emergency.Similarly, the network layer, as seen in figure 1. BAN connected to each other by various networks that are used daily access easily.Such as the Internet and other networks.
We have divided pattern of Inter-BAN communication in two categories, the basic architecture Infrastructure (Figure 3) and the architecture of the base or ad hoc based architecture (Figure 4) when the basic architecture infrastructure was provided.The wide bandwidth with flexibility and centralized control there, since that was spreading quickly, the architectural base has been easy, and we face a dynamic environment.Such as responding to emergency medical care or go to the accident site (Baker CR, Armijo K, Belka S, Benhabib M, Bhargava V et al, 2007).They both have the hardware to facilitate of the routing multi-stage radio (micro radio frequency).Install the same architecture for wireless sensor networks (WSN) is traditional, and both of them have been used repeatedly as an interface to the outside world in WSN, which all sensor nodes or node are routers yet.Hence, they are a single radio message; all communications have the same bandwidth.A concussion occurs so easily.To determine the number of nodes in sensor/actuator and navigation in certain areas usually use a mechanism asynchronous MAC.It is known as CSMA/CA-carrier sense multiple access with collision avoidance, in ZigBee/IEEE 802.15.4 and dealing with collisions.AP variety of these systems has a mesh structure or network.The features are: (1) An extensive radio coverage is achieved, so that a multi-phase release of the data, allowing the best backup patients planets.
(2) Wireless high-speed, flexible can be accessed with a quick emergency response systems, for example, different routing nodes that can spread to the wall (Baker CR, Armijo K, Belka S, Benhabib M, Bhargava V et al 2007) or along the emergency routes ( 6) and (3) can easily spread without the effect of the integrated networks and the AP may whenever necessary to be added.Inter-BAN communication technology includes WLAN, Bluetooth, Zigbee, cellular, 3G Zigbee protocol's ability to support mesh networks.AP WLAN networks with higher speed than cellular networks or groups of the dwelling.

Third Layer: Beyond-BAN Communication
Compare the second and third layer is to figure out how to use communication design in urban areas.In the Connection Settings for these two networks (inter-BAN and beyond-BAN), the gateway is required (Gatewaydissimilar network connection between two computers, two different distinctly communication network to connect).The third layer can facilitate communication coverage rates and schedules an E-health system.The next step is equipped with a licensed healthcare professionals (eg, doctor or nurse) and doesn't have access to patients' medical information via the Internet and cellular networks.Layer beyond-BAN is an important component of the database.The personnel files and medical history database to support the maintenance and preservation.According to doctor's access and priority customer service doctor to inform users that need access.Each time, based on the data relative to the patient, automatic alerts can be sent via remote communication of different abilities.

The Body Sensors
With the advances in circuit design, signal, MEMS-Micro-Electro Mechanical System and body sensors were smaller and wearable devices.Some of the commercially available sensor devices in the area of the body are such as following: Accelerometer ،blood glucose ،blood pressure ،carbon dioxide CO2 ، ECG ،EEG ،EMG ،gyroscope ،pulse oximetry, in addition, many types of sensors that are used in network WSN.Antennas that are placed inside the human body should only make of non-perishable materials and biocompatibility with the body, such as; platinum or titanium circular of spiral fig antenna.

MAC layer
MAC layer here offs between reliability, downtime or latency and energy consumption in terms of the necessity to be able to decide.
Obviously: (Quality of Service-QoS), reliability, downtime or latency works on the executive career, which is reflected in energy consumption, complexity, and a mix of protocols.
MAC protocol for data transmission with QoS has three components: 1. control entry or admission 2. Scheduler QoS 3. Virtual MAC.
Distributed Queuing Body Area Network-DQBAN, general of source 8 in purpose MAC protocol which is the network supports QoS.


Working with the IEEE 802.15.4 standard.


The timing and control algorithms allow time.
 CAPs-contention access periods used for GTSs-guaranteed time slots and CFPs-contentionfree periods.


Working with the IEEE 802.15.6 standard.


Working with the IEEE 802.15.4 standard and combine, those with the new radio technology applied, such as WB-Ultra-Wideband.

First
layer: Intra-BAN communication Second layer: Inter-BAN communication Third layer: Beyond-BAN communication.

Figure 1 .
Figure 1.BAN communication system with three-layered architecture Figure 1.Covering the range of several components that are described that at low levels and high levels indicate and facilitating the creation because of these components, BAN efficient systems for a wide range of applications.Each component is designed to formalize.
and Smart (The development of networking body monitor the physiological signals in the emergency room of waiting area) (Curtis D. Shih, Waterman J. Guttag, Bailey.Etal, 2008) that cables used in directly linking smart.Various commercially available sensors with a personal device (PS), such as a mobile phone or PDA is shown in Fig a2.

Figure 2 .
Figure 2. communication between PS and PDA Figure 3. Infrastructure based architecture

Figure 4 .
Figure 4. Ad hoc based architecture Fig6.Communications of sensor components

Table 1 .
Sensors commonly employed BAN systems and their typical data rates