static channel assignment and routing in multi-radio wireless mesh networks neil tang 3/9/2009

CS541 Advanced Networking 1

Static Channel Assignment and Routing in Static Channel Assignment and Routing in Multi-Radio Wireless Mesh NetworksMulti-Radio Wireless Mesh Networks

Neil TangNeil Tang3/9/20093/9/2009


OutlineOutline References

End-to-End Bandwidth

Problem Definition

Channel Assignment Algorithm

Bandwidth Aware Routing Algorithms

Simulation Results

Conclusions


ReferencesReferences

Tang-MobiHoc’2005: J. Tang, G. Xue and W. Zhang, Interference-aware topology control and QoS routing in multi-channel wireless mesh networks, ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc), 2005 (Acceptance Ratio:14%, Cited by 105 according to Google Scholar), pp. 68-77.


Wireless Mesh Networks (WMNs)Wireless Mesh Networks (WMNs)

Mesh Client

Mesh Router

Mesh Router/Gateway

Mesh Router/Gateway

WLAN Wireless Sensor Network

Cellular Network

Internet

Mesh Router/Gateway

Mesh Router/Gateway

Mesh Router

Wireless Mesh Backbone

Mesh Router


End-to-End BandwidthEnd-to-End Bandwidth

Instance: Link CAP = 1Mbps, single channel and single radio

Connection 1 (A,D)

Connection 2 (E,G)


B

D

A C

F

E

G1/3Mbps

1/3Mbps1/3Mbps

1/3Mbps

1/3Mbps



Instance: Link CAP = 1Mbps, single channel and single radio

Connection 1 (A,D)

Connection 2 (E,G)


B

D

A C

F

E

G0.5Mbps

1Mbps

0.5Mbps

1Mbps

0.5Mbps



Instance: Link CAP = 1Mbps, 3 channels {1,2,3} and 2 radios

Connection 1 (A,D)

Connection 2 (E,G)


B

D

A C

F

E

G1Mbps

1Mbps1Mbps

1Mbps

1Mbps

1

2 3


AssumptionsAssumptions A stationary wireless mesh backbone network

Multiple radios in each node and multiple channels

The same fixed transmission power

Half-duplex and unicast communications

Static channel assignment

MAC layer: 802.11 DCF and scheduling-based


Connectivity GraphConnectivity Graph

A

D

C

F

E

G

B

G(V,E)


Network Topology (Communication Graph)Network Topology (Communication Graph)

A

D

C

F

E

G

B

Network topology GA (V,EA) determined by a channel assignment A{2, {1,3

}

{1,3}

{2,3}

{1,2}

{1,2}

{1,

2

1

1

3

2

3

2

1

3

3

(B,D;3)

3}

3}

3

(A,C;2)

(A,C;1)


Link/Topology InterferenceLink/Topology Interference

A

D

C

F

E

G

B

Network topology GA (V,EA) determined by a channel assignment A{2,3}

{1,3}

{1,3}

{2,3}

{1,2}

{1,2}

{1,3}

2,3

1,2

1,2

3,4

2,3

3,5

2,3

3,5

3,4

3,5

Link Interference: e.g., I(B,D;3) = 4 Topology Interference: e.g., I(GA) = 5

1,1


Channel Assignment ProblemChannel Assignment Problem

Input: a network G and an integer K

minimum INterference Survivable Topology Control (INSTC) problem: seeks a channel assignment A s.t. its corresponding network topology GA is K-connected and has the minimum topology interference.


QoS Routing ProblemQoS Routing ProblemQoS Routing Problem: seeks a source to destination route and a channel assignment s.t. the end-to-end bandwidth requirement is satisfied.

Connection 1 (A,D,0.5Mbps)


B

D

A C

F

E

G


Bandwidth-Aware Routing (BAR) ProblemBandwidth-Aware Routing (BAR) Problem

Link Load L(e) Link Available Bandwidth A(e) = CAP(e) - ∑e’IEeL(e’)

Input: a network topology GA, ρ(s, t, B)

Bandwidth-Aware Routing (BAR) problem: seeks a flow allocation F, s.t. the total s-t flow is B and that ∑e’IEef(e’,ρ) ≤ A(e), for e GA.

Remark: IEe – the set of links interfering with link e. f(e’,ρ) – the flow added to link e’ for establishing ρ.


A Complete QoS Routing Solution A Complete QoS Routing Solution

BAR Algorithm

Feasible solution?

End

Output the solution and update NY

Block the request

Static Channel Assignment Algorithm Network

Topology


Channel Assignment AlgorithmChannel Assignment Algorithm

A

D

C

F

E

G

B

9

9

9 8

7

7

8

6

8

Link Potential Interference (LPI)


Channel Assignment AlgorithmChannel Assignment Algorithm

Theorem. The algorithm correctly computes a channel assignment whose

corresponding network topology is K-connected in O(Kn3 logm + m2) time

Binary search to find Imin andk-connected G’(V,E’), s.t.

LPI(e) Imin, eE’

Assign the “least” used channel

to the link in G’ one by one

based on 4 rules

All Radios assigned?

End

Assign nodes havingunassigned radios withthe “least” used channels

Y

N


Channel Assignment Algorithm Channel Assignment Algorithm (Example) (Example)

Instance: Q=2, Channel = {1,2,3}, K=2

A

D

C

F

E

G

B

3

1

1

3

2

3

3

2

{1,3}

{1,2}

1

{1,2}

{1,3}

{2,3}

{2,3}

{2,3}

2

1

Topology Interference I(GA) = 4

2


Auxiliary Graph ConstructionAuxiliary Graph Construction

A

D

C

F

E

G

B

3

1

1

3

2

3

3

2

{1,3}

{1,2}

1

{1,2}

{1,3}

{2,3}

{2,3}

{2,3}

2

1

2

C1

C2

E1

E2


Auxiliary Graph ConstructionAuxiliary Graph Construction

C1

C2

E1

E2

D3

D1

F3

F1

G

B2 B3

A2 A3


BAR LPBAR LP

Minimize Interference Impact:

Flow Conservation:

Variables:

Interference:

Bandwidth Requirement:


BAR AlgorithmBAR Algorithm

Theorem. The algorithm correctly solves the BAR problem in polynomial time.

Solve the BAR LP

Feasible solution?

End

Output the solution and update NY

Block the request

Construct GA’

Weakness?


Bottleneck CapacityBottleneck Capacity

The Link Bottleneck Capacity of link e, denoted by BC(e) is BC(e) =

mine IEe∈ A(e)/B. The Path Bottleneck Capacity of a single path P, denoted by BC(P), is BC(P) = mine P∈ BC(e).


Maximum Bottleneck Capacity Path (MBCP) Heuristic (Single Path)


QoS RoutingQoS Routing

(n = 25, C = 3, Q = 2, c = 10.9) (n = 40, C = 3, Q = 2, c = 10.9)


QoS RoutingQoS Routing

(n = 40, C = 12, Q = 3, c = 53.9)(n = 40, C = 12, Q = 2, c = 53.9)


ConclusionsConclusions Simulation results show that compared with the CSP scheme, the BAR

scheme improves the system performance by 57% on average.

static channel assignment and routing in multi-radio wireless mesh networks neil tang 3/9/2009

Documents

single channel

minimum topology interference

d connection

link e

single radio connection

radios connection

link cap

network g