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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
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Minimum Latency Broadcasting in Multiradio, Multichannel, Multirate Wireless Meshes JunaidQadir*, Chun Tung Chou+, ArchanMisra++, 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
Outline • Introduction • Network and interference model • Heuristics to construct MLB tree in MR2-MC multi-rate mesh • Simulation • Conclusions
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.
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.
Network and interference model • The system has • C non overlapping orthogonal frequency channels • Each node is equipped with Q radio interfaces where Q <= C. • Inorder to efficiently utilize the network resources, two radiointerfaces at the same node are not tuned to the samechannel. • The channel assignment is done by the following channel assignment algorithms • CCA, VCA and ISNTC
Network and interference model • A graph ,where l and A denote the latency of each link and the channel assignment function, respectively. v u 3 2 1 3 A(u)={2,3} A(v)={1,3}
Network and interference model • Each edge is represented by a • ,where Channel k u v
Network and interference model 400 m 300 m latency A(y)={2,3} l(w, x, 1)=l(w, x, 2)=l(y, z, 3)= 1/5.5 l(w, z, 1)=l(x, y, 2)=1
Network and interference model • Link-layer multicast transmissions • 4-tuple : the node pV 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
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
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)
Multiradio, Multichannel Shortest Path Tree (MSPT) 3 2 S 3 5 2 4 1 3 3 1 1 2 3 7 3 5
Multiradio, Multichannel Shortest Path Tree (MSPT) 3 3 2 3 S 3 5 2 4 1 1 3 1 3 1 3 2 7 3 5 1 2 2 1 2 3
Multi-radio, Multichannel WCDS Tree (MWT) 3 1 1/3 < 2/1 3 1 3 2 S 1 5 2 4 3 3 3 1 2 7 3 5 1 2 3
Multi-radio, Multichannel WCDS Tree (MWT) 3 1 1/3 < 2/1 3 1 3 2 S 1 5 2 4 3 2 3 1 3 5 1 2 3 7 3 3 2 1 1 1 2 3
Locally Parallelized, Multi-radio, Multichannel WCDS Tree (LMT)
Locally Parallelized, Multi-radio, Multichannel WCDS Tree (LMT) 3 1 2 3 B 2 1 2 3 1 |{A, B,C}-{B,C}| / 3 =0 C Channel 2 S |{B,C}| / 1 = 2 1 Channel 3 2 1 A 3 1 3 2 1 1 3 2 1 2 4 2 3 2 1 2 1
Parallelized, Approximate-Shortest, Multi-radio, Multichannel WCDS Tree (PAMT)
S 2 3 1 2 Label=1=latency B 2 1 E 2 3 1 2 A 2 1 2 Label=2 2 D 1 3 C 1 5 N(A,2,1)={B,C,D} N(A,2,1)={B,C}
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 B C CCA 1 2 1 2 1 2 A B C VCA 1 2 1 3 1 4 fixed random
Simulation • INSTC—construct a K-connected graph 1-connected topology
Simulation 100 packets CCA channel assignment
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.
MSPT MWT PAMT LMT