PhD Thesis Proposal Defence


"Power control in wireless ad hoc networks"

by

Mr. Jun Zhang


Abstract:

Power control in mobile and wireless ad hoc networks has received growing
research interest in recent years. The main idea of power control is to
transmit a packet at an appropriately low power level to guarantee its
successful reception,with the objective of maintaining a high throughput
and/or low energy consumption. In this proposal, we study the correlations
that exist among the required transmission power of the successive frames
of IEEE802.11 DCF 4-way handshake to guarantee its successful delivery.
Based on this study we propose power control algorithms that take into
account such correlations.

First, an adaptive power control algorithm based on packet loss/success
count measurement is proposed to improve the network throughput and energy
efficiency. The packet delivery curve is employed to trigger the
adjustment in transmission power in time. The adjustment in transmission
power of RTS, CTS, DATA, and ACK frames is restricted by a finite state
machine to avoid false action.

Secondly, a class of power control algorithm based on interference
prediction is proposed to improve the network throughput and energy
efficiency. We analyze the interference level at the receiver and derive
the constraints of transmission power for successful packet delivery. A
class of correlative power control algorithms is presented according to
this analysis.

From these studies we find that power control at the MAC layer alone has
some limitations and cannot improve the throughput dramatically. Instead,
the design of routing protocols that are Power control driven may help
improve the throughput further. For this purpose, we analyze the
relationship between the network throughput capacity and the transmission
range in ad hoc networks. We find that, for a random two-dimensional
network, a small transmission range improves the network throughput
capacity only when the network scale is quite large. Therefore, our
proposed algorithms are good enough to achieve a near-optimal performance
for general small scale or medium scale networks without modifying the
routing protocol.

Future work includes investigating routing protocols that are
power-control driven to improve the throughput further in large scale
networks, and to address the fairness isue among flows when the assigned
transmission power levels are different.


Date:     		Monday, 25 September 2006

Time:                   3:00p.m.-5:00p.m.

Venue:                  Room 3416
			lifts 17-18

Committee Members:      Dr. Brahim Bensaou (Supervisor)
                        Prof. Mounir Hamdi (Chairperson)
			Dr. Gary Chan
			Dr. Jogesh Muppala


**** ALL are Welcome ****