170 likes | 263 Views
E N D
1. EmberNet – Wireless Networks for Industrial Systems Presented by Ryan WuApril 11, 2003Some slides and figures courtesy EmberNet, Rob Poor and Cliff Bowman
2. Motivation Traditional Wireless Systems for Industry
Point-to-Point
Point-to-Multipoint
Pros v.s. Cons
Structure, planning, signal failures…
New approach:
Wireless Mesh Network
3. To meet the need
The network does not require sophisticated planning and site mapping to achieve reliable communication
Self-configuring, no human assistance needed
Devices are able to transmit without moving
Low error rate
Low cost (energy and $ )
4. Mesh Network:
At least two nodes with two or more paths between them (Redundancy)
E.g. Internet backbone
Pros:
Reliability;
Adaptability;
Scalability
Cons:?
Mesh Network v.s. Peer-to-Peer?
Wireless Mesh Network
5. Outline Communication Architecture
Ember Technology (Nodes and Gateway)
Gradient Routing and Service Discovery
6. Communication-Mesh Network IEEE 802.15.4 (WPAN)
Low rate (250,40,20 kbps at 2.4G/868/915MHz)
Low power (goal: 3 AA for years)
Antennas: 1000 feet in open air, 20dBM
No clear support for network diagnosis
Loss retransmission at higher layer…
7. Ember Networks EmberNet nodes
embedded wireless networking peripheral
900MHz/2.4GHz
3.81 x 5.59 x .76 cm
EmberNet gateways
192 MHz,32 MB SDRAM,
Intrinsyc Linux 4.1 Distribution
8. EmberNet Nodes EmberNet SPI: Synchronous serial hardware interface
Host API provides a simple, consistent interface to the routing, discovery, and service management in the EmberNet Protocol Stack on the EmberNet Node
9. EmberNet Gateway 10 Base-T Ethernet port
16MB Flash, 32 MB SDRAM, diskless
Intrinsyc Linux 4.1 Distribution
EmberNet Protocol Stack, EmberNet View, Apache HTTP Server
10. Design and Programming Distributed task and messaging
Match to available resources (compute, space, etc. )
Exception-based (event driven) msg
Reliability? (when multi-hops…)
11. Ad Hoc Routing Things to consider:
Energy
Scalability
And ?
Traditional routing protocols
Distance vector approach
Link state approach
12. Gradient Ad Hoc Routing Each node is also a router
”Cost” as a measurement, advertising to others
Only the neighboring ones that can delivery at a lower cost will relay the msg
13. More details of GRAd
14. And more … A service point of view
Services are destinations for messages
Service descriptions not unique: (need nodeID)
Change nodeID to represent devices added/lost replaced
Discovery: send msg with discovery flag
Processors could filter messages and drop the not matched ones…
15. And more: Discussion Pros of GRAd
Conceptually simple
Loop free (gradient like)
Limited data to keep at each node
And?
Cons of Grad
Scalability ?
Problems with broadcast ?
Interference and Collision ?
Others ?
16. Discussions Compared with ”smart dust” ?
Compared with ”TinyOS” ?
Other Comments ?
17. Reference
White Paper of EmberNet
Gradient Routing in Ad Hoc Networks
IEEE 802.15.4 http://www.ieee802.org/15/pub/TG4.html
www.ember.com