Page 1 Approximately Maximum Bandwidth Routing for Slotted Wireless Ad Hoc Networks Approximately...

Approximately Maximum Bandwidth Routing Approximately Maximum Bandwidth Routing for Slotted Wireless Ad Hoc Networksfor Slotted Wireless Ad Hoc Networks

Jianping LI

August 29, 2008

WAKAHARA Laboratory

Information Technology Center The University of Tokyo

E-mail: [email protected]

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Routing protocol for Maximum bandwidth

Research Objective

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OutlineOutline

1. Introduction1. Introduction

3.1 Difference 1 from DSR ----- RREP(Route REPly)

3.2 Difference 2 from DSR ----- Information of time slots

3.3 Difference 3 from DSR ----- Bandwidth estimation

5. Conclusion and Future Work

3. MB(Maximum Bandwidth)-DSR

2. DSR(Dynamic Source Routing Protocol)

1.1 Ad hoc networks

2.2 TDMA(Time Division Multiple Access)-based ad hoc networks

4. Evaluation by Simulation

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3. MB-DSR


1.1 Ad hoc networks



Department of Computer Science, University of

Cyprus

No base stations

Easy and low-cost to establish a network

1. Introduction1.1 Ad hoc networks

– Ad hoc networks offer unique benefits and versatility for certain environments and certain applications

– One of the most promising terminal networks in future communications


For complex multimedia applications Ad hoc conditions Earthquake WarMuch bandwidth is necessary.

Multihop

Mutual interference


Slotted wireless ad hoc Slotted wireless ad hoc networksnetworks

Contention-based protocols Contention-based protocols in ad hoc networksin ad hoc networks

1. Introduction1.2 TDMA-based ad hoc networks

For networks with heavy load carrying mixed trafficFor networks with heavy load carrying mixed traffic

Deterministic scheduling Deterministic scheduling

Collision-free packet transmission Collision-free packet transmission

1. Introduction1.2 TDMA-based ad hoc networks

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3. MB-DSR


1.1 Ad hoc networks




DSR : Route Discovery and Route Maintenance

A B C D E

A B C D E (“A”) (“A.B”) (“A.B.C”) (“A.B.C.D”)

RREQ RREQ RREQ RREQ

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3. MB-DSR2. DSR(Dynamic Source Routing Protocol)

1.1 Ad hoc networks



3. MB-DSR

Objective: Objective:

To select the route of To select the route of maximum bandwidthmaximum bandwidth from many routes in from many routes in

order to transfer data for the application.order to transfer data for the application.

R: the number of total routes between node S and node D

• All the RREQs are forwarded as far as the destination node and all the RREPs are generated by the destination node and returned to the source node.

• When route request packets are transferred, the information of time slots is gathered to the destination node.

• Route selecting of maximum bandwidth by destination node

3. MB-DSR--- Characteristics

3. MB-DSR3.1 Difference 1 from DSR --- RREP

3. MB-DSR3.2 Difference 2 from DSR --- Information of time slots

Data structure of RREQ in MB-DSR

3. MB-DSR3.2 Difference 2 from DSR --- Information of time slots

Data structure of RREQ in DSR

Step 1: To estimate the bandwidth of every route stored in the destination node.

wi = min (t/3,gi)

t: the number of total time slots in every link;gi: the number of free time slots in the bottleneck link of route ri; bottleneck link: the link with the minimum number of free time slots in a route

Step 2: To find the largest estimated bandwidth BE by destination node. If there are U(U>1) routes of largest bandwidth BE, go to Step 3.

Step 3: To assign the time slots for U routes in order to get every bandwidth cj (j=1,…,U) of these routes assigned by SAGO-D.

3. MB-DSR3.3 Difference 3 from DSR --- Bandwidth estimation

where

Let BA = max cj , j=1,…,U 　　 BA: Route Bandwidth by MB-DSR

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3. MB-DSR


1.1 Ad hoc networks




0

1

2

3

4

5

6

0 0.2 0.4 0.6 0.8 1

Ratio of free time slots in a network

Num

ber

of a

ssig

ned

time

slot

s in

a r

oute

Zhu's protocol

MB-DSR

Slots: 16

Hops: 8

Iterative calculation in Zhu’s routing protocol

Chenxi Zhu and M. Scott Corson, “Bandwidth Calculation in a TDMA-based Ad Hoc Network”, University of Maryland, 2001


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3. MB-DSR


1.1 Ad hoc networks



The route of maximum bandwidth can be found by MB-DSR, which has the following characteristics:

• All the RREQs are forwarded as far as the destination node and all the RREPs are generated by the destination node and returned to the source node.

• When route request packets are transferred, the information of time slots is gathered to the destination node.

• Route selecting of maximum bandwidth by destination node


Future work: Future work: Improvement of bandwidth estimation of every route.Improvement of bandwidth estimation of every route.

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Thanks for your Thanks for your attention.attention.

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