Wireless sensor networks in autonomic environments

1
Wireless sensor networks in autonomic
environments

• Shuping Liu
• Networking Lab
• HUT

2
Agenda

• What is sensor?
• What is WSN?
• Communication topology
• Why we need it?
• WSN special characters
• Some filed interesting
• A programmable routing for autonomic WSN
• Data dissemination in autonomic WSN

3
What is sensor?
4
What is WSN?

• Habitat monitoring on the Great Duck Island
  (USA Maine. 2002/2003. UCB Intel Atlantic
  Univ.)

5
Communication topology
6
Why we need it?

• Seamless and Ubiquitous communication with the
  real world.
• Wide usages
• Military application
• Environmental application
• Health application
• Home application
• Traffic Surveillance
• Other commercial applications

7
WSN special characters

• Person unattended, inaccessible ? autonomic
• Limited resource power, memory, MPU
• Topology changes / breaks frequently (war field,
  etc.)
• High density employed, broadcast communication
  paradigm (normal ad-hoc networks uses
  point-to-point communications)
• ? Must be self-organized, self-maintaining and
  operate at low duty cycle.

8
Some fields interesting

• Efficient routing
• Data dissemination
• Low power
• Security
• Programming the Ensemble (configuration)
• ? WSN is a new field, especially in autonomic
  environment. I will introduce some work in the
  first two topics in autonomic WSN

9
A programmable routing for autonomic WSN (1/19)

• The goal of a WSN is to collect, process, and
  forward sensed data to other sensor nodes and/or
  base stations.
• Therefore, the proper routing algorithm is
  essential to WSN applications, which must be
  lightweight, due to limited available resources.

10
A programmable routing for autonomic WSN (2/19)

• Several existing routing for WSN
• GPSR Greedy Perimeter Stateless Routing
• GEAR Geographical Energy Aware Routing
• TBF Trajectory Based Routing
• DD Directed-Diffusion
• TTDD Two-Tier Data-Dissemination
• CBM Content-Based Multicast
• RR Rumor-Routing

11
A programmable routing for autonomic WSN (3/19)

• These routings have distinct properties,
• Try to meet the resource-limited requirements
• Different from traditional routing such as
  OSPF,RIP,BGP
• (see table 1 for difference in details)
• Each of them is designed to meet specific goals
  and therefore is not efficient for all
  applications.
• e.g. DD is more energy-efficient than TTDD
  when the number of sink nodes is large, while
  TTDD is better when the number of sink nodes is
  small
• There is a need to have a routing for WSN that
  can adapt to different applications and different
  network conditions ? autonomic WSN

12
A programmable routing for autonomic WSN (4/19)

• Table 1. Comparison of routing services in WSN
  and Traditional Networks

13
A programmable routing for autonomic WSN (5/19)

• Currently, it is very difficult, if not
  impossible, to change a routing service in a
  large WSN because the service is statically
  pre-configured into each node, which is often
  unattended.
• Yu He et. al. in USC propose a programmable
  routing for autonomic WSN.
• Their work includes a universal routing service
  and an autonomic deployment service.

14
A programmable routing for autonomic WSN (6/19)

• The universal routing service allows the
  introduction of different services through its
  tunable parameters and programmable components.
• The deployment service completes the
  configuration of the universal routing service
  throughout a WSN in an autonomic and
  energy-efficient way.
• Through this deployment service, a
  self-configuration ability is realized for sensor
  routing service.
• With the changeable parameters and programmable
  components of the universal routing service, the
  self-optimizing as well as other autonomic
  abilities can be explored.

15
A programmable routing for autonomic WSN (7/19)

• Sensor node architecture with programmable
  routing

16
A programmable routing for autonomic WSN (8/19)

• Table 2. shows the data-forwarding and
  state-collecting functions of the existing
  routing is covered by the programmable structure

17
A programmable routing for autonomic WSN (9/19)

• The suggested architecture is proposed to cover
  all existing routing services and to introduce
  new services for WSN.
• The state information is a list of neighbor
  entries, each of which consists of four parts,
• Neighbor description (id, location,
  direction, distance, energy reading, etc.)
• Neighbor interest (type, rate, duration,
  etc.)
• Neighbor data availability (type, duration,
  etc.)
• Neighbors latest data copy (data, timestamp,
  etc.)
• ? the above state involves only local
  information and thus is scalable

18
A programmable routing for autonomic WSN (10/19)

• Different packets are used to collect each part
  of the state information, (state collecting)
• Neighbor description hello / announcement /
  query packets
• Neighbor interest query packets
• Neighbor data availability announcement /
  data packets
• Neighbor latest data copy data packets

19
A programmable routing for autonomic WSN (11/19)

• The deployment service receives deployment
  packets that contain parameters or modules of the
  programmable routing services and deploy services
  according to packet content.
• There are three levels of deployment,
• (1) the deployment service only changes
  parameters to the state-collecting and/or
  data-forwarding modules. (least bandwidth
  requirement ? relatively frequently)
• (2) either of the two modules is replaced.
  (middle case)
• (3) the entire routing service is changed.
• (most overhead ? only occasionally)

20
A programmable routing for autonomic WSN (12/19)

• Note that this deployment service allows
  different routing services to reside in different
  parts of WSN. For example, GPSR service and RR
  (Rumor-Routing) service can be deployed in
  heterogeneous parts of a WSN.

21
A programmable routing for autonomic WSN (13/19)

• Now let us consider a case with complex routing
  service, then we will deploy a large code.
• Transferring the large routing code can be very
  expensive in WSN where energy is a very scarce
  resource.
• A. Boulis et. al. proposed a separate running
  environment for deployment service. But it is
  computation inefficiency.
• A deployment approach for routing services should
  be both energy-efficient and computation-efficient
  .

22
A programmable routing for autonomic WSN (14/19)

• The approach proposed by Yu He. et. al. is to
  move a part of routing service code into WSN,
  which contains common routing services operations
  and is designed as a shared library, before
  deploying routing service modules.
• With shared library, the written routing modules
  have small code size while keeping the
  computation efficiency.

23
A programmable routing for autonomic WSN (15/19)

• A sample node architecture with shared library

24
A programmable routing for autonomic WSN (16/19)

• The deployment discussed above assumes that all
  nodes in a network can be reached at one time.
• But this is generally not the case for WSN
  because,
• Sensor node is prone to fail due to running
  out of energy
• Communication failure due to lossy channel or
  obstacles
• Sensor node sleep periodically or dynamically
  for some time due to energy-saving mechanisms
• ? inconsistency among nodes for deployed
  services

25
A programmable routing for autonomic WSN (17/19)

• Yu He et. al. proposed a synchronization protocol
  that enables a sensor node to make itself
  consistent with its neighbors in an
  energy-efficient way.
• Each node runs this protocol after waking up from
  sleeping or after a period.
• Each node maintains a version number for each
  deployed component (a parameter or a module).

26
A programmable routing for autonomic WSN (18/19)

• A broadcasts an initial request among its
  neighbors
• ? each neighbors Ni with greater version
  number starts a timer
• ?after timeout, the neighbor sends an initial
  reply to A
• ?A also starts a timer after sending initial
  request
• ?A sends formal request to the node with
  higher version number
• ? reply with formal reply
• ? complete synchronization

27
A programmable routing for autonomic WSN (19/19)

• Deployment synchronization from neighbors

28
Data dissemination in autonomic WSN (1/5)

• In WSNs, data communication, from the point of
  view of the communication entities, can be
  divided into three cases,
• From sensor to a monitoring node
• Among neighboring sensors
• From a monitoring node to sensors

29
Data dissemination in autonomic WSN (2/5)

• Data communication schemes in WSNs

30
Data dissemination in autonomic WSN (3/5)

• Reliable data dissemination is crucial to WSN
  since a monitoring node has to perform some
  specific activities, such as
• Change the operational mode of part or entire
  WSN
• Broadcast a new interest to the network
• Activate / deactivate one or more sensors
• Send queries to the network

31
Data dissemination in autonomic WSN (4/5)

• Max do Val Machado et. al. proposed a new data
  dissemination algorithm, TEDD (Trajectory and
  Energy-based Data Dissemination).
• The key idea is to combine concepts presented in
  TBF (Trajectory-Based Forwarding) with the
  information provided by the energy map of the
  network to determine routes in a dynamic fashion,
  according to the energy level of the sensor nodes.

32
Data dissemination in autonomic WSN (5/5)

• Simulation result revealed that the energy spent
  with the data dissemination activity can be
  concentrated on nodes with high-energy reserves,
  whereas low-energy node can use their energy only
  to perform sensing activity or to receive
  information addressed to them.

33
Thanks!Any comments and questions?