Throughput-Oriented MAC for Mobile Ad Hoc Networks with Variable Packet Sizes Fan Wang, Ossama Younis, and Marwan Krunz Department of Electrical & Computer engineering University of Arizona, Tucson 3rd Annual IEEE Communications Society on Sensor and Ad Hoc Communications and Networks (SECON), vol.2, pp , Sept. 2006

Outline Introduction Introduction Related work Related work Theoretical background Theoretical background –Game theory Proposed MAC Protocols Proposed MAC Protocols –TOMAC-D –TOMAC-S Performance evaluation Performance evaluation Conclusion Conclusion

Introduction Improving the network throughput is a primary objective in MANETs Improving the network throughput is a primary objective in MANETs Transmission power control (TPC) was proposed for improving spatial resue and reducing energy consumption Transmission power control (TPC) was proposed for improving spatial resue and reducing energy consumption

Introduction scheme is over-conservative scheme is over-conservative –RTS/CTS silence all overhearing terminals –Fixed transmission power are used by all terminals Network throughput can be significantly improved by using TPC Network throughput can be significantly improved by using TPC

Optimal link scheduling

Link scheduling in POWMAC [8] – JSAC, 2005

Link scheduling in GMAC [9] - WiOpt, 2006

Theoretical background Utility function Utility function P i : Transmission power of link i P -i : the TPs of all links other than i γ i : SINR α i p i : pricing function, α i = 1/P max

Standard non-cooperative game problem

Players ’ best response functions (7) Can be reduced into the following matrix-form expression H: a n*n matrix representing the channel gains between each transmission pairs G: an n*1 vector, where

Back-to-back scheduling To optimally schedule a link, a processing complexity of O (m n ) To optimally schedule a link, a processing complexity of O (m n ) Two rules to lower the scheduling complexity Two rules to lower the scheduling complexity –An already scheduled link is not re- scheduled in the AW –A contending link can not be scheduled at the beginning of the DW, should checks the smallest unoccupied space

Space list for back-to- back transmission

Operation of TOMAC-D Worst Fit

Operation of TOMAC-S Using all frames in it ’ s queue

Other design issues Computing the AW size Computing the AW size –Using a default threshold, increase/decrease 1 slot each round Contention resolution Contention resolution –Using a modified scheme to lower the overhead of contention

Other design issues Overhead Overhead – Out-regional slave terminal Out-regional slave terminal –Data transmission of out-regional transmitter does not add significant interference to the master receiver –A transmitter within two master regions is prohibited from contending S c : size of control packet S d : size of data packet N: slots of the AW n: average number of concurrent links

Performance evaluation Simulator: CSIM Simulator: CSIM Two-ray propagation model with a path loss factor of 4 Two-ray propagation model with a path loss factor of 4 Nodes are randomly distributed Nodes are randomly distributed DATA generation: Poisson process with the same λ DATA generation: Poisson process with the same λ 1 Mbps, SINR threshold is 6 dB, Max Transmission range is 750 M 1 Mbps, SINR threshold is 6 dB, Max Transmission range is 750 M

Network goodput in a 500x500 meters 2

Energy consumption in a 500x500 meters 2

Number of admitted links in a 500x500 meters 2

Network goodput in a 1500x1500 meters 2

Energy consumption in a 1500x1500 meters 2

Network goodput in a 1500x1500 meters 2

Energy consumption in a 1500x1500 meters 2

Network goodput in a 1500x1500 meters 2

Conclusion Two throughput-oriented MAC protocols are proposed Two throughput-oriented MAC protocols are proposed –Inspired by game theory Throughput gains come at no additional energy consumption cost Throughput gains come at no additional energy consumption cost

Thank you!!