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Static Channel Assignment and Routing in Multi-Radio Wireless Mesh Networks Neil Tang 3/9/2009. Outline. References End-to-End Bandwidth Problem Definition Channel Assignment Algorithm Bandwidth Aware Routing Algorithms Simulation Results Conclusions. References.
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Static Channel Assignment and Routing in Multi-Radio Wireless Mesh NetworksNeil Tang3/9/2009 CS541 Advanced Networking
Outline • References • End-to-End Bandwidth • Problem Definition • Channel Assignment Algorithm • Bandwidth Aware Routing Algorithms • Simulation Results • Conclusions CS541 Advanced Networking
References 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. CS541 Advanced Networking
Wireless Mesh Networks (WMNs) Internet Mesh Router/Gateway Mesh Router Mesh Router Mesh Router/Gateway Wireless Mesh Backbone Mesh Router Mesh Router/Gateway Mesh Router/Gateway Cellular Network WLAN Wireless Sensor Network Mesh Client CS541 Advanced Networking
End-to-End Bandwidth • Instance: Link CAP = 1Mbps, single channel and single radio • Connection 1 (A,D) • Connection 2 (E,G) 1/3Mbps 1/3Mbps F D B 1/3Mbps Wireless Mesh Backbone G 1/3Mbps 1/3Mbps C E A CS541 Advanced Networking
End-to-End Bandwidth • Instance: Link CAP = 1Mbps, single channel and single radio • Connection 1 (A,D) • Connection 2 (E,G) 0.5Mbps 1Mbps 0.5Mbps F D B Wireless Mesh Backbone 0.5Mbps G 1Mbps C E A CS541 Advanced Networking
End-to-End Bandwidth • Instance: Link CAP = 1Mbps, 3 channels {1,2,3} and 2 radios • Connection 1 (A,D) • Connection 2 (E,G) 1Mbps 1Mbps F D B 1Mbps Wireless Mesh Backbone G 2 3 1Mbps 1Mbps C E A 1 CS541 Advanced Networking
Assumptions • 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 CS541 Advanced Networking
Connectivity Graph G(V,E) D F B G A C E CS541 Advanced Networking
Network Topology (Communication Graph) Network topology GA (V,EA) determined by a channel assignment A {1,3} {2, 3} 3 D F {1, 3} 3 B 3 (B,D;3) 1 2 3 G {1,3} 1 3 (A,C;2) 2 A C E 2 1 {1,2} {2,3} {1,2} (A,C;1) CS541 Advanced Networking
Link/Topology Interference Network topology GA (V,EA) determined by a channel assignment A {1,3} {2,3} 3,5 D F {1,3} 3,4 B 3,5 1,1 2,3 3,5 G {1,3} 1,2 3,4 2,3 A C E 2,3 1,2 {1,2} {2,3} {1,2} Link Interference: e.g., I(B,D;3) = 4 Topology Interference: e.g., I(GA) = 5 CS541 Advanced Networking
Channel 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. CS541 Advanced Networking
QoS Routing Problem QoS 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) F D B Wireless Mesh Backbone G C E A CS541 Advanced Networking
Bandwidth-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. CS541 Advanced Networking
A Complete QoS Routing Solution Static Channel Assignment Algorithm BAR Algorithm Network Topology Feasible solution? Output the solution and update Block the request Y N End CS541 Advanced Networking
Link Potential Interference (LPI) Channel Assignment Algorithm 9 D F 8 7 B 9 8 G 6 7 8 9 A C E CS541 Advanced Networking
Channel Assignment Algorithm Binary search to find Imin and k-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? Assign nodes having unassigned radios with the “least” used channels N Y End Theorem. The algorithm correctly computes a channel assignment whose corresponding network topology is K-connected in O(Kn3 logm + m2) time CS541 Advanced Networking
Channel Assignment Algorithm (Example) {1,3} {1,3} 3 D F {2,3} 3 1 3 B 1 1 G {2,3} 3 2 Instance: Q=2, Channel = {1,2,3}, K=2 2 2 1 A C E 2 {2,3} {1,2} {1,2} Topology Interference I(GA) = 4 CS541 Advanced Networking
{1,3} {1,3} Auxiliary Graph Construction 3 D F {2,3} 3 1 3 B 1 1 G {2,3} 3 2 2 2 1 A C E 2 {2,3} {1,2} {1,2} C1 E1 C2 E2 CS541 Advanced Networking
Auxiliary Graph Construction D3 F3 B2 B3 D1 F1 G A2 A3 C1 E1 C2 E2 CS541 Advanced Networking
BAR LP Minimize Interference Impact: Flow Conservation: Bandwidth Requirement: Interference: Variables: CS541 Advanced Networking
Construct GA’ Solve the BAR LP BAR Algorithm Feasible solution? Output the solution and update Block the request Y N End Theorem. The algorithm correctly solves the BAR problem in polynomial time. Weakness? CS541 Advanced Networking
Bottleneck Capacity The Link Bottleneck Capacityof link e, denoted by BC(e) is BC(e) = mine∈IEeA(e)/B. The Path Bottleneck Capacityof a single path P, denoted by BC(P), is BC(P) = mine∈PBC(e). CS541 Advanced Networking
Maximum Bottleneck Capacity Path (MBCP) Heuristic (Single Path) CS541 Advanced Networking
Maximum Bottleneck Capacity Path (MBCP) Heuristic (Single Path) CS541 Advanced Networking
QoS Routing (n = 25, C = 3, Q = 2, c = 10.9) (n = 40, C = 3, Q = 2, c = 10.9) CS541 Advanced Networking
QoS Routing (n = 40, C = 12, Q = 2, c = 53.9) (n = 40, C = 12, Q = 3, c = 53.9) CS541 Advanced Networking
Conclusions • Simulation results show that compared with the CSP scheme, the BAR scheme improves the system performance by 57% on average. CS541 Advanced Networking