1 Minimum Latency Broadcasting in Multiradio, Multichannel, Multirate Wireless Meshes Junaid Qadir*, Chun Tung Chou+, Archan Misra ++, and Joo Ghee Lim.

1

Minimum Latency Broadcasting in Multiradio, Multichannel, Multirate

Wireless Meshes

Junaid Qadir*, Chun Tung Chou+, Archan Misra++, and Joo Ghee Lim+

* National University of Sciences and Technology, Islamabad, Pakistan.+University of New South Wales, Sydney, Australia

++Applied Research, Telcordia Technologies,

IEEE/ACM TRANSACTIONS ON MOBILE COMPUTING, VOL. 8, NO. 11, NOVEMBER 2009

2

Outline

Introduction Network and interference model Heuristics to construct MLB tree in MR2-MC

multi-rate mesh Simulation Conclusions

3

Introduction

A wireless mesh network is a multihop wireless network consisting of A large number of wireless nodes Some gateway nodes and connected with a wired

network. However, low spatial reuse of a single radio

channel (due to wireless interference) poses an impediment to the widespread adoption of WMN as a viable access technology.

4

Introduction

The minimum latency broadcasting (MLB) problem is particularly challenging in Multi-Radio, Multi-Hop Wireless Mesh Networks

How to support “efficient” broadcast in such networks is an important issue.

5

Network and interference model

The system has C non overlapping orthogonal frequency channels Each node is equipped with Q radio interfaces

where Q <= C. In order to efficiently utilize the network

resources, two radio interfaces at the same node are not tuned to the same channel.

The channel assignment is done by the following channel assignment algorithms CCA, VCA and ISNTC

6

Network and interference model

A graph ,where l and A denote the latency of each link and the channel assignment function, respectively.

vu 23 1 3

A(u)={2,3} A(v)={1,3}

7

Network and interference model

Each edge is represented by a ,where

vuChannel k

8

Network and interference model

A(y)={2,3}

l(w, x, 1)=l(w, x, 2)=l(y, z, 3)= 1/5.5

300 m

l(w, z, 1)=l(x, y, 2)=1

400 m

latency

9

Network and interference model

Link-layer multicast transmissions 4-tuple : the node p V is to transmit to all

the nodes in the set I V in a link-layer multicast using latency l on channel k.

For , the following are required

10

Problem statement

Given the graph , and the broadcast source node s, the objective is to find a set of link-layer multicast transmissions such that: The union of all links from all the transmissions

forms a spanning tree on G The broadcast latency is minimized

11

Heuristics to construct MLB tree in MR2-MC multi-rate mesh

Multiradio, Multichannel Shortest Path Tree (MSPT)

Multi-radio, Multichannel WCDS Tree (MWT) Locally Parallelized, Multi-radio, Multichannel

WCDS Tree (LMT) Parallelized, Approximate-Shortest, Multi-

radio, Multichannel WCDS Tree (PAMT)

12

Multiradio, Multichannel Shortest Path Tree (MSPT)

13

Multiradio, Multichannel Shortest Path Tree (MSPT)

S

2 311

2

3

3

2

3

7

53

3

54

1

2 3 14

Multiradio, Multichannel Shortest Path Tree (MSPT)

S

1

1

1

2

3

3

2

3

7

53

3

54

1

2

3

2

3

3

2

1

1

15

Multi-radio, Multichannel WCDS Tree (MWT)

2 3 16

Multi-radio, Multichannel WCDS Tree (MWT)

S

1

2

1

1

3

2

3

7

53

3

54

3

3

3

1/3 2/1<

1

2

1

2 3 17

Multi-radio, Multichannel WCDS Tree (MWT)

S

1

1

1

1

3

2

3

7

33

3

54

3

3

3

2

2

1

3

1

2

5

1

1

21/3 2/1<

18

Locally Parallelized, Multi-radio, Multichannel WCDS Tree (LMT)

19

Locally Parallelized, Multi-radio, Multichannel WCDS Tree (LMT)

A

B

CS

1

3

2

3

3

2

1

31

1

2 1

2 1

Channel 2|{B,C}| / 1 = 2Channel 3

|{A, B,C}-{B,C}| / 3 =0

3

2 32 4

2 1

2 1

2 1

2 3

1

1

20

Parallelized, Approximate-Shortest, Multi-radio, Multichannel WCDS Tree (PAMT)

21

C1 5

B 12

A 12

E 32

S 32

D 31

Label=1=latency

Label=2

1

2

12

2

2

N(A,2,1)={B,C,D} N(A,2,1)={B,C}

22

Simulation

N nodes are randomly located in an area of 1200m * 1200 m

three channel assignment schemes in our current work: CCA, VCA, and INSTC

A

1

CCA

2

B

1 2

A

1

VCA

2

B

1 3

C

1 2

C

1 4

fixed random

23

Simulation

INSTC—construct a K-connected graph

1-connected topology

24

25

26

VCA, INSTC > CCA

27

Simulation

CCA channel assignment100 packets

28CCA channel assignment

29

Conclusions

The authors proposed four heuristic algorithm for MR2-MC WMNs

PAMT outperforms the other algorithms The performance of CCA (which usually

performs poorly for unicast flows) is generally better than both VCA and INSTC.

30

Thank you~

31

MSPT

LMT PAMT

MWT