Leach module
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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

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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

    • 很難各別去置換sensor或是它的電池

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


能量消耗模組


Problem of energy consumption

Sensor node

Base station


Problem of energy consumption (cont.)

Sensor node

Base station


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的圖解


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.


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 (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的flow chart


Installation

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


LEACH module


Mobile node

cmu-trace.cc

mac-sensor-timer.cc

mac-sensor.cc

wireless-phy.cc


Resource-Adaptive node

rcagent.cc

resource.cc

ns-ranode.tcl

rca-all.cc

energy.cc


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

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

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

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


Final project


ACT : Adaptive Colored Threshold


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 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


流程圖


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 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

  • 環境

    • NS2

    • field of 100 * 100

    • base station (50 , 170)

    • initial battery capacity of 2 Joules


metrics


Result (heat source module)


Result (heat oscillation module)


Result (wave front module)


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


Thank you


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


hierarchical clustering scheme


TEEN的運作示意圖


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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