multicast algorithms for multi- channel wireless mesh networks guokai zeng, bo wang, yong ding, li...
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Multicast Algorithms for Multi-Channel Wireless Mesh Networks
Guokai Zeng, Bo Wang, Yong Ding, Li Xiao, Matt Mutka
Department of Computer Science and EngineeringMichigan State University
IEEE International Conference on Network Protocols (ICNP 2007)
Outline
Introduction System Model Multicast Algorithms Simulation Conclusion
Introduction
Mesh networks are characterized by the use of multiple channels and multiple interfaces
There are three types of nodes in wireless mesh networks Gateways (access points)
Enable the integration of WMNs with various other networks, including the Internet
Mesh routers Minimal mobility and form the mesh backbone Equipped with multiple wireless interfaces
Mesh clients End users, such as laptops and PDAs Within one-hop of the mesh routers
Introduction
Video On Demand poses a big challenge for the limited bandwidth of WMNs
However, traditional multicast protocols assume that each node is equipped with one interface
Goals
To improve the system throughput by allowing simultaneous close-by transmissions with multi-channel and multi-interface
To assign all the available channels to the interfaces instead of just the non-overlapping channels
System Model
Partial Overlap Assumptions
System Model_ Partial Overlap
Some researches assume that 802.11b/g only use three non-overlapping channels: 1, 6, and 11 binary interference model
R
R’
Assume R’ = 2R
Channel 1
Channel 6
System Model_ Partial Overlap
R
R’
Channel 1
Channel 6
R
R’
Channel 5
R
δt is Interference Factor, channel separation of two links is tEx: δ0=2, δ6=0
Interference range = R * δt
System Model_ Assumptions
The following assumptions for Mesh routers Limited mobility Don’t rely on battery power Equipped 2 interface Multi-channel
Multicast Algorithms
Level Channel Assignment Algorithm (LCA) Multi-Channel Multicast Algorithm
Multicast Structure Construction Broadcast Structure Multicast Structure
Channel Assignment Ascending Channel Allocation Heuristic Channel Assignment
Failure Recovery
Multicast Algorithms_ Level Channel Assignment Algorithm (LCA)
s
a b
c e
fh
ij
s
a b
c e
fh
ij
Level 0
Level 1
Level 2
Level 3
d
gd
g
0 00
1 11 1 1
22 2
2
3
2
3Network Topology
Multicast Tree
Multicast Algorithms
The goals of Multi-Channel Multicast Algorithm Minimizing the delay Minimal number of relay nodes
Broadcast Structure Multicast Structure
Multicast Algorithms
Level Channel Assignment Algorithm (LCA) Multi-Channel Multicast Algorithm
Multicast Structure Construction Broadcast Structure Multicast Structure
Channel Assignment Ascending Channel Allocation Heuristic Channel Assignment
Failure Recovery
Multicast Algorithms_ Broadcast Structure
s
a b
c e
fh
ij
s Level 0
Level 1
Level 2
Level 3
d
g
Network Topology Tree Mesh
BFS
h i j
a b
c d e
f g
Broadcast Structure_ Find Relay node
Relay node
Level i+1
1.Find minimal number of parents
c db
1 2 3 4 5 6 7
a
{1,5,7}
2.Find the maximal number of children From {a,c,d}
,and their parent of set{1,5,7} is {a,c,d}
a
1 2 3
aa
c d
c
4 5
c d
6 7
d
Multicast Algorithms_ Broadcast Structure
s
Broadcast Tree
h i j
a b
c d e
f g
Relay node
a
d ec
Top-Down
Multicast Algorithms
Level Channel Assignment Algorithm (LCA) Multi-Channel Multicast Algorithm
Multicast Structure Construction Broadcast Structure Multicast Structure
Channel Assignment Ascending Channel Allocation Heuristic Channel Assignment
Failure Recovery
Multicast Algorithms_ Multicast Structure
s
Multicast Tree
h i j
a b
c d e
f g
Relay node
b
c
Bottom-up
a
Multicast member node
Multicast Algorithms
Level Channel Assignment Algorithm (LCA) Multi-Channel Multicast Algorithm
Multicast Structure Construction Broadcast Structure Multicast Structure
Channel Assignment Ascending Channel Allocation Heuristic Channel Assignment
Failure Recovery
Multicast Algorithms_ Ascending Channel Allocation
s
i j
a b
c d e
f g
0 00
11 1
2
2
00 0
1
1 1
Receive-interface (RI) Send-interface (SI)
Available Channel = 3
channel = 0
channel = ( channel + 1 ) mod 3
Multicast Algorithms
Level Channel Assignment Algorithm (LCA) Multi-Channel Multicast Algorithm
Multicast Structure Construction Broadcast Structure Multicast Structure
Channel Assignment Ascending Channel Allocation Heuristic Channel Assignment
Failure Recovery
Multicast Algorithms_ Heuristic Channel Assignment
indicates the interference range of sender uof one link with respect to sender v of another link
channelu v
channel RR
Multicast Algorithms
Level Channel Assignment Algorithm (LCA) Multi-Channel Multicast Algorithm
Multicast Structure Construction Broadcast Structure Multicast Structure
Channel Assignment Ascending Channel Allocation Heuristic Channel Assignment
Failure Recovery
Multicast Algorithms_ Failure Recovery
Tree construction
1
8
2
7
11
Node 5 break down
1.Find Relay node
2.Random select Relay node
Recovery
9
3
4
10
6
Simulation_ Parameters
NS2 simulator (version 2.29) 900m * 900m Flat area Transmission range is 250m Carrier sensing range is 550m Default IEEE 802.11 MAC Packet size is set to be 512 bytes.
Simulation_ Impact of Network Size
Simulation_ Impact of Number of Available Channels
Simulation_ impact of Number of Transmission Rate
Simulation_ Delay Comparison
Simulation_ Partially Overlapping Channel Test
Conclusion
Two multicast algorithms, LCA and MCM, are proposed by using multi-channel and multi-interface
The performance evaluation shows that algorithms and channel assignment can further improve throughput and reduce delay
Thank You~