ad hoc wireless networks

2002 년 2 학기 이동인터넷프로토콜 1

Ad Hoc Wireless Networks


Agenda

• Ad Hoc Network• Issues• Power Conservation Approaches• Routing Protocols• Energy Conservation at the Network Layer


Ad hoc network

• A collection of two or more devices equipped with wireless communications and networking capability (Infrastructure-less Infrastructure)

• Every node can forward packets• Self-organizing, adaptive• IETF WG

– MANET (Mobile Ad hoc Network)

• http://www.ietf.org/html.charters/manet-charter.html

http://www.ietf.org/html.charters/manet-charter.html






Ad Hoc Network

ad hoc network Infrastructured network

● ●

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●

■BS

● ●

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●

●

이동단말기가 Router 역할 수행 유선으로 연결된 BS 을 통하여 통신


Ad Hoc Network

• 3 Groups (G1, G2, G3)

A has data to send to H A looks for a route to H through G

A finds the route


Ad Hoc Network

• Applications– Conferencing

– Home Networking

– Emergency Services

– Personal Area Networks (PAN) and Bluetooth

– Embedded Computing Applications (PDA etc.)

– Sensor Networks


Ad Hoc Network

• Issues– Spectrum Allocation and Purchase

– Media Access

– Routing

– Multicasting

– Energy Efficiency

– TCP Performance

– Security & Privacy


Protocol Layer Power Conservation Techniques

• Data-Link Layer– MAC (Media Access Control) – IEEE802.11

• Network Layer– Routing Protocol

• Transport Layer– TCP Performance


Data-Link Layer

• Avoid unnecessary retransmissions• Avoid collisions • Put receiver in standby mode whenever possible• Use/allocate contiguous slots for transmission and

reception whenever possible• Turn radio off (sleep) when not transmitting or

receiving


Network Layer

• Consider route relaying load• Consider battery life in route selection• Reduce frequency of sending control message• Optimize size of control headers• Efficient route reconfiguration techniques


Transport Layer

• Avoid repeated retransmissions• Handle packet loss in a localized manner• Use power-efficient error control schemes


Routing

• New routing protocols for Ad Hoc networks are needed– OSPF

• Link-state protocol

• High bandwidth required to maintain a current view of the network

– RIP• Distance-vector algorithm

• Very slow convergence (count to infinity)


Ad Hoc Routing Protocols

AD-HOC MOBILEROUTING PROTOCOLS

TABLE DRIVEN/PROACTIVE

ON-DEMAND-DRIVEN/REACTIVE

HYBRID

DSDV WRP

CGSR STAR

DSR ABR

TORA AODV

CBRP RDMAR

ZRP


Routing Protocols• Proactive (Table driven)

– DSDV (Destination Sequenced Distance vector)– WRP (Wireless Routing Protocol)– CSGR (Cluster Switch Gateway Routing)

• Reactive (On-demand-driven)– AODV (Ad Hoc On-Demand Distance Vector Routing) : RREQ, RREP– DSR (Dynamic Source Routing) – use cache– SSR (Signal Stability Routing)– PAR (Power-Aware Routing)– ABR (Associativity-Based Long Lived Routing)

• Hybrid– ZRP (Zone Routing Protocol)


DSDV

• Destination Sequenced Distance Vector– Charles E. Perkins

• Table-driven• Based on Bellman-Ford routing algo.• Full dump & incremental packet• Too many overhead for Ad hoc


AODV

• Ad Hoc On-Demand Distance Vector Routing– Charles E. Perkins, Elizabeth M. Royer

• Improvement on DSDV• RREQ, RREP• Support only bidirectioinal link


AODV

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination


AODV

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination

Propagation of the RREQ

RREQ Broadcast

Each node adds previous node to its routing table (to establish a reverse path)


AODV

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination

Path of the RREP to the source

RREQ


AODV

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination

Sending Data

Data


DSR

• Dynamic Source Routing– David B. Johnson (Carnegie-Mellon Univ.)

• Two major phase– Route discovery

• On cache misses

– Route maintenance• Use cache -> Router Error packet (passive ack)

• Support unidirectioinal links


DSR

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination


DSR


N1

N1-N2

N1-N2-N5

N1

N1-N3

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination

N1-N3-N4

N1-N3-N4

N1-N3-N4

N1-N3-N4-N6

N1-N3-N4-N7


DSR

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination

Propagation of the route reply with the route record

N1-N2-N5-N8 N1-N2-N5-N8

N1-N2-N5-N8


DSR

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination

Sending Data (by Source Routing)

Data


ABR

• Associativity-Based Long Lived Routing– C-K Toh

• Consider– Associativity Ticks/Counts

– Link Delay

– Signal Strength

– Power Life

– Route Relay Load


ZRP

• Zone Routing Protocol– Haas, Pearlman (Cornell University)

• Proactive + Reactive– Intrazone (Routing Zone) - Proactive

• IARP(Intrazone Routing protocol) – Interzone - Reactive

• BRP(Bordercast Routing protocol)

• IERP(Interzone Routing Protocol)


Energy conservation

Ad Hoc routing


Geography-informed Energy Conservation for Ad Hoc Routing

Ya Xu, John Heidemann, Deborah Estrin

ACM/IEEE Mobicom2001


Abstract

• GAF– Geographical Adaptive Fidelity

• Use application- and system-level info.• Independent of underlying ad hoc routing protocol

(DSR, AODV)


Introduction

• Energy dissipation in idle state cannot be ignored• Routing fidelity

– Uninterrupted connectivity between communication nodes

• Employ location info (from GPS, etc.)


Introduction

1 4

3

2

5

1Nominal radio range


Energy-conserving routing

• Virtual grid– All nodes in a particular grid square are equivalent with

respect to forwarding packets

– For two adjacent grids A and B, all nodes in A can communicate with al nodes in B and vice versa

– Based on the nominal radio range R


Determining node equivalence

1 4

3

2

5

r rr

A B C

5

)2( 222

Rr

Rrr


GAF State Transition

• Three states– Sleeping (Ts)

– Discovery (Td)• Discovery message

– node id, grid id, enat(estimated node active time)

– Active (Ta)• Periodically re-broadcast its discovery msg at intervals Td


GAF State Transition

sleeping

discovery

activeafter Ts

after Td

after Ta

receive discovery msg from high rank nodes


Tuning GAF

• enat (estimated node active time)– enlt/2

• enlt : time to use up all remaining energy

• Td (discovery message interval)– A uniform random value between 0 and some constant

• Ta– enat

• Ts– Uniformly in [enat/2, enat]


Tuning GAF

• Node Ranking– Accorting to remaining energy level…

1. A node in active state has higher rank than a node in discovery state

2. For nodes with same state, GAF gives nodes with longer enat higher rank


Adapting to high mobility

• engt (expected node grid time)– In the discovery message

– Ts < engt

– engt = r/s• s : current speed of a node

• GAF-b (basic)• GAF-ma (mobility adaption)


Simulation

• 50 mobile nodes – random waypoint model by Johnson, CMU

– Speed : 0~1 m/s, 0~20 m/s

– Nominal range : 250m

• Area – 1500m x 300m

• Pause times (0~900ms)

• Traffic – CBR UDP

– 1, 10, 20 pkts/sec by 10 traffic nodes


Simulation

• Energy Model– AT&T 2Mb/s WaveLAN

• 1.6W for transmit

• 1.2W for receiving

• 1.0W for listening

• 0.025W for sleeping


Simulation

Network lifetime comparisons : GAF-b vs. AODV at low node speed (1m/s) under various pause time. Movement : 1m/s, traffic : 20 pkts/s

In case of AODV, all

nodes die out around 450ms!!


Simulation


BECT: A Balanced Energy Consumption Algorithm by Threshold-Tuning for Mobile Ad Hoc Networks

2002. 11. 1

Real Time Internet Lab.Jaeho Chang


Agenda

• DSR– Dynamic Routing Protocol

• BECT– DSR modification

– Energy-Balancing by Threshold Tuning

• Simulation• Conclusion & Future Work


DSR

• Dynamic Source Routing– Monarch Project (CMU)

• http://www.monarch.cs.rice.edu

– On-demand wireless Ad Hoc routing protocol

– Source routing

– Promiscuous mode (overhear), cache

• Two major phase– Route discovery

• RREQ, RREP msg

– Route maintenance• On receiving RERR msg -> cache -> Route Discovery

http://www.monarch.cs.rice.edu/

http://www.monarch.cs.rice.edu/


DSR


N1

N1-N2

N1-N2-N5

N1

N1-N3

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination

N1-N3-N4

N1-N3-N4

N1-N3-N4

N1-N3-N4-N6

N1-N3-N4-N7


DSR

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination

Propagation of the route reply with the route record

N1-N2-N5-N8 N1-N2-N5-N8

N1-N2-N5-N8


DSR

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination


DSR

N1 N2N3

N4 N5

N8N7

N6

Source Destination


BECT

• BECT– Energy-Balancing by Threshold Tuning

– Two phases• Route Discovery by Threshold

• Route Change by Threshold


BECT

N1

N2

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N5N8

N7

N6

Source

Destination

RREQ (th)

RREQ (th)RREQ (th)


BECT (Route Discovery)

N1

N2

N3

N4

N5N8

N7

N6

Source

Destination

Data


Basic Operation 1

N1 N2N3

N4 N5

N8N7

N6

Source (th) DestinationRREQ (th)

Route Change by Threshold


Basic Operation 2

N1 N2N3

N4 N5

N8N7

N6

Source (th) DestinationN1-N3-N5N1-N4-N5-N2N1-N6-N7-N8-N2

RREP


N1 N2N3

N4 N5

N8N7

N6

DestinationN1-N3-N5N1-N4-N5-N2N1-N6-N7-N8-N2

Basic Operation 3

Data (th)

Source (th)


N1 N2N3

N4 N5

N8N7

N6


Basic Operation 4

Data (th)

Source (th)


N1 N2N3

N4 N5

N8N7

N6


Basic Operation 5

Source (th)

data (th)


N1 N2N3

N4 N5

N8N7

N6


Basic Operation 6

Source (th)


Basic Operation 7

N1 N2N3

N4 N5

N8N7

N6

DestinationRREQ (th-c)

Source (th-c)


Basic Operation 8

N1 N2N3

N4 N5

N8N7

N6


RREP

Source (th-c)


N1 N2N3

N4 N5

N8N7

N6


Basic Operation 9

Data (th-c)

Source (th-c)


BECT Algorithm

• Addition to DSR– Node

• EnergyThreshold

• EnergySelf = INIT_ENERGY – EnergyComsumed

– Packet Headers• EnergyThreshold

– data, rreq, rrep, rerr packet


BECT Algorithm

• Threshold Tuning– 보내는 모든 packet 에 자신의 Th 추가– 수신 또는 overhear 하는 모든 packet

• Packet th < 자신의 th 이면 자신의 th tuning

• Route Discovery– RREQ 시 자신의 th 삽입

• 중간 노드에서 RREQ 수신시 packet th > 자기 E 이면 drop

– SRC 에서 RREP 못받으면 th 낮추어 다시 RREQ• THRESHOLD_RESOLUTION


BECT Algorithm

• 중간노드 Data 전송– Data packet 의 th > 자신의 E 이면 , drop 없이 RERR

• Packet th > E – (Th_resolution*0.2) 이면 RRER

N1 N2 N3 N4 DestinationSource

N5N6

N7

N8


BECT Algorithm (Summary)

Node Action

Source When initiating a RREQ;

Set ethp to ethn;

When a RREQ timeout;

ethn -= eth_dec;

Initiate a new RREQ;

When receiving or overhearing packets;

If ethn > ethp, then set ethn to ethp;

Intermediate When receiving a RREQ;

If rel < ethp, then drop the RREQ;

When forwarding a data packet;

If ethp > (rel – eth_dec / m), then initiate a RERR;

When receiving or overhearing packets;


Destination When receiving or overhearing packets;



Simulation

N1 N2N3

N4 N5

N8N7

N6

DestinationSource


Simulation (Simple Topology)

t

DSR

BECT

t

tt1 t2 t3 t4 t5 t6

N1-N3-N2

N1-N4-N5-N2

N1-N6-N7-N8-N2

Path

t1 t2 t3 t4 t5 t6

N1-N3-N2

N1-N4-N5-N2

N1-N6-N7-N8-N2

Path

N1 N2N3

N4 N5

N8N7N6

DestinationSource


Simulation (GloMoSim)

• SIMULATION-TIME 900S• TERRAIN-DIMENSIONS (1000, 1000)• NUMBER-OF-NODES 50• NODE-PLACEMENT UNIFORM/RANDOM• ROUTING-PROTOCOL DSR/BECT• Traffic

– cbr– 10 /20 sources– Packet size : 128/512/1024 Bytes– Packet Interval : 5 packets/s

• Movement– Random-waypoint

• pause time : 0/100/300/600/900 sec• speed : min 0, max 1 m/s


Simulation

• Energy Model– Lucent 2Mb/s WaveLAN 802.11 cards.

• 1.4W for transmit

• 1.0W for receiving

• 0.83W for listening/idle

• 0.043W for sleeping


Simulation (Avg Consumed Energy)

2.250

2.300

2.350

2.400

2.450

2.500

2.550

2.600

2.650

0 100 300 600 900

pause time

Ener

gy C

onsu

mpt

ion

(mW

hr)

DSRBECT (1)BECT (0.2)

4.650

4.700

4.750

4.800

4.850

4.900

4.950

5.000

5.050

0 100 300 600 900

pause time

Ener

gy C

onsu

mpt

ion

(mW

hr)


10 src 20src


Simulation (Standard Deviation)

10 src 20src

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

0 100 300 600 900

pause time

Stan

dard

Dev

iati

on (

mW

hr)


0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

0 100 300 600 900

pause time

Stan

dard

Dev

iati

on (

mW

hr)



Simulation (Data Delivery Fraction)

10 src 20src

0.940

0.950

0.960

0.970

0.980

0.990

1.000

0 100 300 600 900

pause time

Dat

a D

eliv

ery

Frac

tion


0.960

0.965

0.970

0.975

0.980

0 100 300 600 900

pause time

Dat

a D

eliv

ery

Frac

tion



Simulation (Control Overhead Fraction)

10 src 20src

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0 100 300 600 900

pause time

Con

trol

Ove

rhea

d


0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0 100 300 600 900

pause time

Con

trol

Ove

rhea

d


ad hoc wireless networks

Documents

routing table

routing protocolsad

routingnew routing protocols

bellmanford routing

wireless networks cs

network layercs

source routingdatacs

dsrsending data