AARON LEE 1 Energy-Limited Wireless Networking with Directional Antennas: The Case of Session-Based Multicasting Jeffrey E. Wieselthier, Gam D. Nguyen Naval Research Laboratory INFOCOM 2002

AARON LEE2 Outline InstructionModel Algorithm for Broadcasting and Multicasting with Directional Antennas –Reduced Beam MIP –D-MIP Performance Results Conclusions

AARON LEE3 Instruction Develop a multicasting algorithms – –suitable for use in networks with directional antennas – –Improve MIP to D-MIP – –limited battery capability – –compare performance with omnidirectional environment Energy-efficient operation does not ensure good performance in energy-constrained applications

AARON LEE4 Model The network consists of N nodes, which are randomly distributed over a specified region. Each node has T transceivers, and can thus support up to T multicast sessions simultaneously. There is a total of F frequencies available to the network.

AARON LEE5 Model Multicast requests and session durations are generated randomly at the network nodes. Each multicast group consists of the source node plus at least one destination node. The set of nodes that support a multicast session is referred to as a multicast tree.

AARON LEE6 Model Propagation Model –Received signal power is –Received power threshold =1 –Omnidirectional antennas –Directional antennas

AARON LEE7 Model Energy Expenditure

AARON LEE8 Model Performance Measures –Delivered traffic Volume Each destination node Each destination node participating in multicast session i receives

AARON LEE9 Model Performance Measures –Delivered traffic volume per unit energy The energy expenditure in session i is

AARON LEE10 Algorithm for Broadcasting and Multicasting with Directional Antennas Reduced Beam MIP (RB-MIP) – –First, a low-cost broadcast or multicast tree is formed, using any tree-construction algorithm – –Second, each transmitting node’s antenna beamwidth is reduced to the smallest possible value that provides coverage of the node’s downstream neighbors

AARON LEE11 Algorithm for Broadcasting and Multicasting with Directional Antennas Directional MIP(D-MIP) –MIP (Multicast Incremental Power) MIP is similar in principle to Prim’s algorithm for the formation of minimum-cost spanning trees (MSTs) New nodes are added to the tree one at a time incremental cost = j k i h j k i h

AARON LEE12 Algorithm for Broadcasting and Multicasting with Directional Antennas Example Broadcast Tree

AARON LEE13 Algorithm for Broadcasting and Multicasting with Directional Antennas Example Broadcast Tree

AARON LEE14 Algorithm for Broadcasting and Multicasting with Directional Antennas Example Broadcast Tree

AARON LEE15 Algorithm for Broadcasting and Multicasting with Directional Antennas The Incorporation of Energy Limitations

AARON LEE16 Performance Results Number of Nodes = 50 region with dimensions 5 x 5 RF power values of r 2 to support a link between two nodes that are separated by distance r. initial energy at each node is 200 β = 0, 0.5, 1, and 2.

AARON LEE17 Performance Results Network Lifetime

AARON LEE18 Performance Results Delivered Traffic Volume

AARON LEE19 Performance Results

AARON LEE20 Performance Results

AARON LEE21 Performance Results

AARON LEE22 Performance Results

AARON LEE23 Conclusions Reduced-Beamwidth MIP (RBMIP), uses the trees formed by MIP under the assumption of omnidirectional antennas, and then reduces the beamwidth to concentrate the RF energy in the cone where it is needed. Directional-MIP (D-MIP), exploits the directionality of the antennas throughout the tree-construction process.

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AARON LEE25 Prim’s Algorithm

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