a load aware hybrid channel assignment for multi-radio wireless mesh network

8/8/2019 A Load Aware Hybrid Channel Assignment for Multi-Radio Wireless Mesh Network

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A Load Aware Hybrid Channel

Assignment for Multi-Radio

Wireless Mesh Network

Tran Minh Trung

[email protected]


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Multi-channel, Multi radio

Mesh router Mesh router:Multiple interfaces

Each interface can workon multiple channels

Challenges

How to assign channel for each interface?How to decide when to transmit packets

and which interface will be used?

Mesh

router

IF1

IF2

Mesh

router

IF1

IF2

Mesh

router

IF1

IF2


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Channel assignment

Dynamic

StaticHybrid

Scheduling algorithm

CSMA/CD

TDMA

Existing approaches

Can utilize the

advantage of both

dynamic and static

mechanisms


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Hybrid mechanism

Hybrid mechanism

Some interfaces fixed on a channel

Different nodes use different fixed channels

Other interfaces switch as needed Dynamic assignment

Mesh

router

IF1

IF2

Mesh

router

IF2

IF2

Mesh

router

IF2

IF2

c1

c2

c3

c4


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Fixed interface contention problem

4

6

5

8

1

2

3

2

7

9

C(6)=1

C(7)=1

C(4)=1

9 links contending on a single channel


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Net-X:

Equalize the # of fixed interfaces on each channel

Problem: Each node have different traffic load and

contention degree

Proposed solution:

Load aware channel assignment

Solution approaches


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Load aware channel assignment

4

6

5

8

1

2

3

2

7

9

C(4) = 2

C(6) = 1

C(7) = 1

C(5) = ?

Channel ID # Fixed

Interface

Contention

Deg.

1 2 2

2 1 4

Net-X: FC(5)= 2

Proposed solution: FC(5)=1


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Channel selection procedures

Step 1: Initializing

Nodes choose the same common channel

Broadcast hello message including channel status table

Step 2: Selecting channel Select channel basing on contention degree information

If contention degrees are equal -> select channel basing on thenumber of fixed interface on each channel

Step 3: Finalizing

Update channel status basing on new selected channel

Broadcast new channel status on common channel

Switch channel from common channel to selected channel


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Simulation parameters (2)

param.topo maxx: 1000(m)

maxy: 1000(m)

nnodes: 36

type: [1:random 2:manual]

param.mac Slotted base

framesize: 10 (~20ms) slotsize: 1 (~2ms)

allocatetype: [1 2 3] 1: Hop based

2: Load based 3: Hybrid

param.phy txrange: 250 (m)

nchannel: 1-5

linkrate: 2 Mbps

swtime: 0.0500 (~0.1ms)

Pktsize = 512bytes

param.conn method: [1 2]

1: Random

type: [1 2]

1: CBR

param.route Type: [1] 1: Min-hops


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Simulation result

The throughput of three different channel

assignment algorithms


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Conclusions

Utilize both advantage of dynamic and static

mechanisms

Avoids co-ordination issues, deafness problems

Retain flexibility of dynamic assignment

Easy for implementation (more realistic)

Modify existing 802.11 protocol

Can be implemented in user space daemon


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References

1. Akyildiz, I.F., Wang, X. and Wang, W., ``Wireless Mesh Networks: A Survey,'' Computer

Networks Journal (Elsevier), March 2005

2. Pradeep Kyasanur and Nitin H. Vaidya, Routing and Interface Assignment in Multi-Channel

Multi-Interface Wireless Networks, in WCNC, 2005.

3. Richard Draves, Jitendra Padhye, and Brian Zill, Routing in Multi-Radio, Multi-Hop Wireless

Mesh Networks, in ACM Mobicom, 2004.4. Ashish Raniwala, Kartik Gopalan, and Tzi-cker Chiueh, Centralized Channel Assignment and

Routing Algorithms for Multi-Channel Wireless Mesh Networks, Mobile Computing and

Communications Review, vol. 8, no. 2, pp. 5065, April 2004.

5. Jungmin So and Nitin H. Vaidya, Multi-channel MAC for Ad Hoc Networks: Handling Multi-

Channel Hidden Terminals using a Single Transceiver, in Mobihoc, 2004.

6. P. Bahl, R. Chandra, and J. Dunagan, SSCH: Slotted Seeded Channel Hopping for CapacityImprovement in IEEE 802.11 Ad-Hoc Wireless Networks, in ACM Mobicom, 2004.

7. Shih-Lin Wu, Chih-Yu Lin, Yu-Chee Tseng, and Jang-Ping Sheu, A New Multi-Channe MAC

Protocol with On-Demand Channel Assignment for Multi-Hop Mobile Ad Hoc Net works, in

International Symposium on Parallel Architectures, Algorithms and Network (ISPAN), 2000


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Appendix

Implementation


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Implementation architecture


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Channel selection procedure

a load aware hybrid channel assignment for multi-radio wireless mesh network

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