LEACH

WIRELESS  SENSOR NETWORK SIMULATION


INTRODUCTION

  • A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants.

INTRODUCTION

  • The Wireless Sensor protocol examined in this study is           Low Energy Adaptive Clustering Hierarchy LEACH.

  • It has the functionality of dividing the sensor nodes into groups (clusters) which are managed by a coordinator node called the cluster head (CH).
  • These are the ones that then transmit the data to the destination data sink or base station(BS)

LEACH PROTOCOL (1)

  • Layered routing protocol for WSN with self organisation and dynamic cluster formation giving the advantage of low energy consumption and long survival time.

  • The sensor nodes in a WSN based on the LEACH protocol have three operational activities with respect to data :

 -   acquisition
-   processing
-  transmission


LEACH PROTOCOL(2)

  • Operation of LEACH is split into two phases: Setup phase and Steady state phases with the duration time of each know as a round. 
  • Setup phase has the following:

 Cluster-Head advertisement, 

 Cluster setup

 Transmission 

schedule creation 

  •  Each sensor node generates a random number  0-1 and used to  select the Cluster heads for the Clusters

 

LEACH PROTOCOL(3)

  • In the Steady-state phase the main operation is maintaining the CH while data is transmitting between the nodes with the operations: 

Data transmission to CH 

Signal processing 

Data transmission to the base  station. 



LEACH PROTOCOL(4)

  •  Cluster-head Advertisement
  •  Let x be the random # between 0 and 1, n is the given node, P is the cluster-head probability, r is the current round, G is the set of nodes that were not cluster-heads the previous rounds.
  • If x as operation according to the T(n) equation.
  • Nodes that are cluster-heads in round 0 can’t be again next 1/P rounds ; after 1/P - 1, the threshold value will be T(n)=1
  • In 1/P rounds, all nodes are eligible again to become cluster-heads
  • After the election of cluster head, each of the  nodes will broadcasts an advertisement message to the rest of the nodes by using a CSMA MAC protocol. 

LEACH PROTOCOL(5)

Steady-state phase algorithm: 

The following occurs once the cluster enters the steady-state phase:

  • Begin sensing and transmitting data to the cluster- heads.

  • Then, the cluster-head node, receive all the data, aggregates it before sending it to the base-station. 

  •  After a certain time, which is determined a priori, the network goes back into the setup phase. 

SIMULATION(1)

  • NS3 is not backward compatible with NS2; it’s built from the scratch to replace NS2.

  • NS3 is written in C++, Python Programming Language can be optionally used as an interface.

  • NS3 is trying to solve problems present in NS2.
  • There is very limited number of contributed codes made with NS3 compared to NS2

  • NS-3 generates pcap packet trace files; other utilities such as Wireshark can be used to analyse traces as well. 

SIMULATION(2)

LEACH parameters: Cluster type Dynamic Cluster Heads percentage (Cluster Heads selection cycle 1.00)

Number of Nodes             50

Network size                   100 X 100

Initial Battery power                  0.75

Sensors that elect to CH                     5% of total sensors 

Dead nodes            1
Base Station Position          X=99 Y=99

ADV broadcast Distance              25

Trials               15   

SIMULATION(3)

Simulation cast https://asciinema.org/a/9544

RESULTS(1)


RESULTS(2)


RESULTS(3)


CONCLUSION

  • The energy of the network decreases rapidly and then increase and so on in 2 minutes , as shown in Results graphs.

  • This is because the effective of transmitting and receiving data in the network. In LEACH protocol we have the limited energy. In it we have a given interval after a given interval of time; a randomised rotation of the role of the CH is conducted so that uniform energy dissipation in the sensor network is obtained. 

  • In LEACH protocol more energy is consumed because of head changes, advertisements etc. 

QUESTIONS




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