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LEACH module

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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  1. LEACH module 林政龍

  2. Outline • Introduction • LEACH (Low-Energy Adaptive Clustering Hierarchy) • Installation • LEACH module

  3. 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.

  4. 能量消耗模組

  5. Problem of energy consumption Sensor node Base station

  6. Problem of energy consumption (cont.) Sensor node Base station

  7. 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

  8. LEACH的圖解

  9. 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.

  10. 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

  11. 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

  12. LEACH的flow chart

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

  14. LEACH module

  15. Mobile node cmu-trace.cc mac-sensor-timer.cc mac-sensor.cc wireless-phy.cc

  16. Resource-Adaptive node rcagent.cc resource.cc ns-ranode.tcl rca-all.cc energy.cc

  17. 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

  18. Reference • http://nslab.ee.ntu.edu.tw/NetworkSeminar/slides/EDACH.ppt • http://www.internetworkflow.com/resources/ns2leach.pdf • http://www.internetworkflow.com/downloads/ns2leach/

  19. Final project

  20. ACT : Adaptive Colored Threshold

  21. 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

  22. Temporal 與Spatial 圖解(sensor node端)

  23. 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

  24. 流程圖

  25. 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 :

  26. 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

  27. Simulation • 環境 • NS2 • field of 100 * 100 • base station (50 , 170) • initial battery capacity of 2 Joules

  28. metrics

  29. Result (heat source module)

  30. Result (heat oscillation module)

  31. Result (wave front module)

  32. 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

  33. Thank you

  34. 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

  35. hierarchical clustering scheme

  36. TEEN的運作示意圖

  37. 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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