Lecture 5B: Wireless Personal Area Network Flashcards
1
Q
WPAN Technology Standards (IEEE 802.15)
A
- Bluetooth (IEEE 802.15.1-2005)
- Ultrawideband (IEEE 802.15.3c-2009)
- Zigbee & Low rate technologies (IEEE 802.15.4)
- Body Area Networks (IEEE 802.15.6)
- Visible Light Communications (IEEE 802.15.7)
2
Q
Wireless Sensor Networks
A
- Enable reliable monitoring and analysis of unknown and untested environments
- Useful for continuous and regular monitoring such as facility and environmental sampling security and surviellance, health care monitoring, and underwater measurments
- These are a collection o tiny disposable and low power sensor devices
3
Q
Wireless Sensor Networks (Cont. 1)
A
- A sensor node is a device that convert a sensed attribute (e.g. temperture, vibration) into a form understandable by users
- Includes a sensing module, a communication module, and typically a small battery.
- The number of sensors can be large to cover as much as desirable
- Sensor networks are usually unattended and some degree of fault-tolerance needed.
4
Q
Wireless Sensor Network (cont.2)
A
- Wireless sensor networks are the newest members of one special class of wireless ad hoc networks wherein a large number of tiny and low power immobile wireless sensors are planted on an ad hoc basis to sense and transmit some physical characteristics of the environment.
- An associated BS (Base Station) collects the information gathered by the sensors on a data-centric basis.
5
Q
Advantages of Wireless Sensor Networks
A
- Ease of deployment
- Extended range
- One single huge wired sensor can be replaced by many similar wireless sensors for the same cost.
- A network of smaller wireless sensors can be distributed over a wider region
- Fault tolerance
- Failiure of one node may not affect the network operation, as there are other nodes collecting similar data
- Mobility (some)
6
Q
ZigBee and IEEE 802.15.4
A
- Zigbee is pertinent in various wireless sensor applications.
- Based upon IEEE 802.15.4 - Low Rate WPANs Standard
- Sometimes preferable to have low-speed, low power wireless devices
- The device size can be dramatically reduced/
- IEEE 802.15.4 standard addresses requirements for RF transmissions requiring low consumption and cost.
- Sometimes preferable to have low-speed, low power wireless devices
7
Q
ZeeBee Standard
A
- Provides for the connectivity of simple statoinary and mobile devices
- Low data rates between 20 and 250 Kbps
- Consume a minimum amount of power
- Designed to be short in range
- Typically connect at distances of 33 feet (10 meter) to 150 feet (50 meters)
8
Q
Zeebee
A
- ZigBee is a control technology that works by standardizing an existing wireless networking powered by small batteries, requiring low bandwidth and low latency and low energy consumption for the long operational lifetiime of network devices.
- ZigBee specification
- Based on the relatively low-level performance requirements of sensor and control systems
9
Q
ZigBee (cont. 1)
A
- ZigBee: low-power, short-range, and low-data rate specification that is based on 803.15.4 but that includes standards for network configuration, security, and other high-level features
- Typically found in the following applications:
- Smart lighting
- Advanced temperature control
- Medical data collection
- Smoke and intruder detection
10
Q
ZigBee (cont. 2)
A
- ZigBee network with many ZigBee devices can cover a large area since
- ZigBee specification and IEEE 802.15.4 standards include full Mesh networking.
- Some ZigBee devices have the ability to route packets to other devices.
- Each ZigBee network can simultaneously support up to 65,536 nodes
- Each device has a 16-bit node address
- So a ZigBee network can have 216= 65,536 devices
- Ideal for sensors and control applications: heating, cooling, security, lighting, and smoke and CO detector systems, etc
11
Q
ZigBee vs. Bluetooth
A
- Both ZigBee and Bluetooth occupy the category of low-data-rate WPAN.
- However, ZigBee focus on control and automation with a very low data rate and low power consumption, while
- Bluetooth focuses on connectivity between consumer electronics products such as laptops, PDAs, mice and keyboards with the intent of replacing cable connections.
12
Q
ZigBee vs. Bluetooth (cont.)
A
- Bluetooth requires a higher data rate and higher power consumption for continous data forwarding and receiving.
- The lifetime of Bluetooth applications is short compared with that of ZigBee applications, which must operate for years without the need to replace the power source.
- In time-critical applications, ZigBee is designed to respond quickly, while Bluetooth takes much longer to respond.
13
Q
ZigBee Overview
A
- ZigBee specification
- Based on the relatively low-level performance requirments of sensors and control systems
- ZigBee devices are designed to remain quiescent for long periods of time - use very little power
- ZigBee transmissions are designed to be short in range
- Spec includes full-mesh networking - some ZigBee devices have the ability to route packets to other devices
14
Q
ZigBee Protocol Stack
A
- Based on the OSI seven-layer model
- Defines only those layers that are relevant to achieving specific functionality
15
Q
ZigBee Protocol Stack (cont. 1)
A
- The upper layers include specific procedure that devices use to join a network (called an association), leave a network (called a disassociation), apply security to frames, and perform routing. Also responsible for device discovery, maintaining routing tables, and storing information about neighbor devices.
- MAC layer handles all access from the upper layers to the physical radio channel
- The Logic Link Control (LLC) is responsible for managing the data-link communication, link addressing, defining service access point, and frame sequencing.
