Challenges

Wireless Sensor Network

Wireless Body Area Sensor Network

Scale

Monitored environment (meters/kilometers)

Human body (centimeters/meters)

Node Number

Many redundant nodes for wide area coverage

Fewer, limited in space

Result accuracy

Through node redundancy

Through node accuracy and robustness

Node Tasks

Node performs a dedicated task

Node performs multiple tasks

Node Size

Small is preferred, but not important

Small is essential

Network Topology

Very likely to be fixed or static

More variable due to body movement

Data Rates

Most often homogeneous

Most often heterogeneous

Node Replacement

Performed easily, nodes even disposable

Replacement of implanted nodes difficult

Node Lifetime

Several years/months

Several years/months, smaller battery capacity

Power Supply

Accessible and likely to be replaced more easily and frequently

Inaccessible and difficult to replace in an implantable setting

Power Demand

Likely to be large, energy supply easier

Likely to be lower, energy supply more difficult

Energy Scavenging Source

Most likely solar and wind power

Most likely motion (vibration) and thermal (body heat)

Biocompatibility

Not a consideration in most applications

A must for implants and some external sensors

Security Level

Lower

Higher, to protect patient information

Impact of Data Loss

Likely to be compensated by redundant nodes

More significant, may require additional measures to ensure QoS and real-time data delivery.

Wireless Technology

Bluetooth, ZigBee, GPRS, WLAN, . . .

Low power technology required

Node Tasks

Node performs a dedicated task

Node performs multiple tasks

Node Size

Small is preferred, but not important

Small is essential

Network Topology

Very likely to be fixed or static

More variable due to body movement