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LEACH module. 林政龍. Outline. Introduction LEACH (Low-Energy Adaptive Clustering Hierarchy) Installation LEACH module. WSN (wireless sensor network). Sensor node 的能力 Sensing Process communication Sensor node 的特色 量多 ( hundreds or thousands of sensor nodes ), 體積小 , 夠便宜 電池供電 衍生問題

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Leach module

LEACH module

林政龍


Outline
Outline

  • Introduction

  • LEACH (Low-Energy Adaptive Clustering Hierarchy)

  • Installation

  • LEACH module


Wsn wireless sensor network
WSN (wireless sensor network)

  • Sensor node的能力

    • Sensing

    • Process

    • communication

  • Sensor node的特色

    • 量多(hundreds or thousands of sensor nodes), 體積小, 夠便宜

    • 電池供電

  • 衍生問題

    • 很難各別去置換sensor或是它的電池

    • power conservation is a critical design issue for routing protocol.



Problem of en ergy consumption
Problem of energy consumption

Sensor node

Base station


Problem of en ergy consumption cont
Problem of energy consumption (cont.)

Sensor node

Base station


Leach low energy adaptive clustering hierarchy
LEACH (Low-Energy Adaptive Clustering Hierarchy)

  • Employs randomized rotation of the cluster-heads to evenly distribute the energy load among the sensor nodes in the network


Leach
LEACH的圖解


Leach cont
LEACH (cont.)

  • The operation is divided into rounds.

  • Each of these rounds consists of 2 phases: a set-up phase and a steady-state phase.

  • During the set-up phase cluster-heads are determined and the clusters are organized.

  • During the steady-state phase data trans-ference to the base station occurs.


Leach cont1

Cluster-head election process : (the same as LEACH)

A sensor determines whether to become a cluster

head by generating a random number

and compare this value with a threshold

A node becomes a cluster head if the random number

is less than a threshold

LEACH (cont.)

P,the desired percentage to become a cluster-head;

the set of nodes that have not being selected as a cluster-head in the last 1/P rounds.

r,the current round


Leach cont2
LEACH (cont.)

  • 形成cluster後,cluster-head會排定TDMA schedule給屬於相同cluster的non-cluster傳輸的時槽(time slot),已決定每個non-cluster傳輸時間

  • 等待cluster-head收集完non-cluster的資料後,便將資料傳給BS

  • ㄧ開始cluster-head發送adv.給所有的sensor nodes 與sensor nodes 加入某個cluster是利用CSMA機制,之後non-cluster傳輸資料給cluster或是cluster收集完資料,再將資料傳送給BS,都是利用CDMA的機制去傳輸資料


Leach flow chart
LEACH的flow chart


Installation
Installation

  • http://www.internetworkflow.com/downloads/ns2leach/



Mobile node
Mobile node

cmu-trace.cc

mac-sensor-timer.cc

mac-sensor.cc

wireless-phy.cc


Resource adaptive node
Resource-Adaptive node

rcagent.cc

resource.cc

ns-ranode.tcl

rca-all.cc

energy.cc


Leach1
LEACH程式結構

Leach主程式

執行

Wireless.tcl

Leach.tcl

ns-leach.tcl

設定參數

uamps.tcl

執行base station的功能

ns-ranode.tcl

ns-bsapp.tcl

ns-resource-manager.tcl

extras.tcl

ns-energy-resource.tcl

stats.tcl

ns-neighbor-resource.tcl

Resource Adaptive Node

統計產生檔案


Reference
Reference

  • http://nslab.ee.ntu.edu.tw/NetworkSeminar/slides/EDACH.ppt

  • http://www.internetworkflow.com/resources/ns2leach.pdf

  • http://www.internetworkflow.com/downloads/ns2leach/




Act scheme
ACT scheme

  • 提出了temporal suppression與spatial suppression兩種抑制傳輸,目的是為了達到energy efficient,但省energy卻會造成傳回給BS的資料有精確性的問題,所以又提出α值來使誤差降至最低


Temporal spatial sensor node
Temporal 與Spatial 圖解(sensor node端)


α的選定

  • 為了使誤差降至最低,因此,提出了下列公式,來選定α為最小誤差值

  • SV為sensor node的前一輪的感測值

  • dj為cluster-head目前的感測值

  • di為sensor node目前的感測值



Temporal spatial bs 1
Temporal 與 Spatial (BS端) (1)

  • 若sensor node並未達到suppression的條件,會將完整的感測值傳回給BS,因此,BS可以得到正確的感測資料,便不需要執行估計的程序,反之,若BS未得到sensor node的感測值,就必須根據下列公式來估計其sensor node的感測值 :


Temporal spatial bs 2
Temporal 與 Spatial (BS端) (2)

  • SV為temporal的估計值,將直接採用sensor node最後傳給BS的感測值當估計值

  • 為spatial的估計值,利用線性方程式 求得斜率m與截距b後,再使用兩點內插法或外插法來求得估計值


Simulation
Simulation

  • 環境

    • NS2

    • field of 100 * 100

    • base station (50 , 170)

    • initial battery capacity of 2 Joules






Conclusion
Conclusion

  • proposed the Adaptive Color Threshold (ACT) scheme to provide priority treatments to enhance the efficiency of redundancy suppression

  • 利用α、temporal及spatial的機制來提升sensor node被抑制感測值的精確度



Introduction teen
Introduction TEEN

  • TEEN : Threshold sensitive Energy Efficient sensor Network protocol

    • Good for time-critical applications

    • This sensor network model likes LEACH uses a hierarchical clustering scheme

    • Cluster headers broadcast:

      • Hard Threshold

        • This is a threshold value for the sensed attribute

      • Soft Threshold

        • This is a small change in the value of the sensed attribute which triggers the node to switch on its transmitter and transmit



TEEN的運作示意圖


Leach and teen
LEACH and TEEN

  • LEACH

    • Abstract: Reelect Cluster head (CH) each round

      • Advantage: Load balance

      • Disadvantage: Data Redundancy

  • TEEN

    • Abstract: Hard and soft threshold

      • Advantage: Reduce similar data to transmit at each node

      • Disadvantage:

        • Thresholds are fixed

        • 無法得知node存亡

        • 沒有考慮環境的變化,資料重要性相同


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