sChat: A Group Communication Service Over Wireless Sensor Networks Fei Sun, Chien-Liang Fok, Gruia-Catalin Roman Washington University in St. Louis This research was supported by the NSF under NOSS grant CNS-0520220. Mobile Computing Laboratory Motivation Wireless sensornets are more robust and less likely to fail in disaster scenarios They can serve as an alternative medium through which rescuers can communicate Problem Statement The sensornet is initially deployed for some other purpose (e.g., environmental monitoring) Users (rescuers) must remain in contact with each other while continuously moving. Limited resources Membership? Unreliable wireless links Join - Member agents can join a specific group to exchange messages within the group. A group is formed when the first member joins. Leave - A member agent can leave a specific group to stop sending or receiving messages within the group. A group is disbanded when the last member leaves. Send - Member agents can send messages that will be forwarded Approach Implement the group communication service on top of Agilla, a mobile agent middleware for sensornets Each user has a member agent in the network that “follows” the user and handles communication between the user and the group TinyOS Node (1,1) Tuplespace Neighbors Agilla Middleware MICA2 Mote Agents TinyOS Node (2,1) Tuplespace Neighbors Agilla Middleware MICA2 Mote Agents migrate remote access Mobile agents move and clone across nodes can be dynamically injected Simplifies development high-level agent abstraction context discovery multi-hop geographic greedy routing The leader agent keeps track of member locations and distributes group broadcast messages The registry keeps track of leader location Supported Operations Agilla Middleware <“mbr”, enumerator, agent id, location> Enumerator: iterative access for broadcast Agent id: random access for member location updates When a user moves, it “drags” its member to its new location. Member updates its new location with leader when it is dragged. User injects a new member if it fails to drag its old member. Leader Tuplespace Leader Agent M em ber Agent M em ber Agent M em ber Agent R egistry PDA PDA PDA sensornet

sChat: A Group Communication Service Over Wireless Sensor Networks

Download PPT Report

Upload
honorato-hurley
View
16
Download
2

Tags:

Embed Size (px)

DESCRIPTION

Neighbors. Neighbors. sChat: A Group Communication Service Over Wireless Sensor Networks Fei Sun, Chien-Liang Fok, Gruia-Catalin Roman Washington University in St. Louis. Mobile Computing Laboratory. Approach. Motivation. - PowerPoint PPT Presentation

Citation preview

sChat: A Group Communication Service Over Wireless Sensor Networks

Fei Sun, Chien-Liang Fok, Gruia-Catalin RomanWashington University in St. Louis

This research was supported by the NSF under NOSS grant CNS-0520220.

Mobile Computing Laboratory

Motivation Wireless sensornets are more robust

and less likely to fail in disaster scenarios

They can serve as an alternative medium through which rescuers can communicate

Problem Statement The sensornet is initially

deployed for some other purpose (e.g., environmental monitoring)

Users (rescuers) must remain in contact with each other while continuously moving.

Limited resources Membership? Unreliable wireless links

Join - Member agents can join a specific group to exchange messages within the group. A group is formed when the first member joins.

Leave - A member agent can leave a specific group to stop sending or receiving messages within the group. A group is disbanded when the last member leaves.

Send - Member agents can send messages that will be forwarded to all the other members in the same group.

Approach Implement the group communication

service on top of Agilla, a mobile agent middleware for sensornets

Each user has a member agent in the network that “follows” the user and handles communication between the user and the group

TinyOS

Node (1,1)

TuplespaceNeighbors

Agilla Middleware

MICA2 Mote

Agents

TinyOS

Node (2,1)

Tuplespace Neighbors

Agilla Middleware

MICA2 Mote

Agents

migrate

remote access

Mobile agents move and clone across nodescan be dynamically injected

Simplifies developmenthigh-level agent abstractioncontext discoverymulti-hop geographic greedy

routing

The leader agent keeps track of member locations and distributes group broadcast messages

The registry keeps track of leader location

Supported OperationsAgilla Middleware

<“mbr”, enumerator, agent id, location>

Enumerator: iterative access for broadcast

Agent id: random access for member location updates

When a user moves, it “drags” its member to its new location. Member updates its new location with leader when it is dragged. User injects a new member if it fails to drag its old member.

Leader Tuplespace

LeaderAgent

MemberAgent

Registry

PDA

PDA PDA

sensornet