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Power Control For Distributed MAC Protocols in Wireless Ad Hoc Networks. Wei Wang, Vikram Srinivasan, Kee-Chaing Chua Department of Electrical and Computer Engineering National University of Singapore. IEEE TMC, Vol. 7, No. 10, October 2008. Outline. Introduction
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Power Control For Distributed MAC Protocols in Wireless Ad Hoc Networks Wei Wang, Vikram Srinivasan, Kee-Chaing Chua Department of Electrical and Computer Engineering National University of Singapore IEEE TMC, Vol. 7, No. 10, October 2008
Outline • Introduction • RTS/CTS-based system model and discussion • Spatial utilization in other distributed MACs • Experimental results • Conclusions
Introduction • Power control MAC protocols in wireless ad hoc networks • Increasing the efficiency of space-time utilization • Reducing the transmission power • Causing the less interference to nearby receivers Hidden terminal problem 4 way handshake Exposed terminal problem power control
System model • The received power • SINR (β)
RTS/CTS-based discussion • Max tolerated interference i dij j k
Avoid the collision problem • Power level of CTS
The minimum transmission floor RTS i j CTS dij Min TR floor reserved = the union of the area (RTS/CTS) Optimal power control scheme
Impact of the optimal TR on transport throughput • The maximal No. of simultaneous transmission pairs • The maximal transport throughput =
Discussion of power control in routing • Fixed link length • Transport throughput can at most be improved by a constant factor • Heterogeneous link length • Short link • Tolerate the more interference • Increase the simultaneous transmssion
Spatial utilization in other distributed MACs • The power control model work on other MAC protocols • Rate-adaptive MAC • Lower rate, lower interference • Physical carrier sensing • Larger effective range than TR • Busy tone • Higher spatial utilization
Experimental Setting • NS 2.28
Comparison • Power control schemes • NTPC, TPC-O, TPC-L1, TPC-L2, TPC-E • Scenario • String topology • Random topology • 500 m *500 m and 200 nodes
Experiment results • Random Networks
Experiment results • Random Networks for different routing with fixed link length
Experiment results • Random Networks for different routing with heterogeneous link length • 40 - 400 nodes
Conclusions • In distributed MAC systems • Optimal transmission floor area • Improve the transport throughput • The system complexity and massage overhead are higher