IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 57, NO. 3, MAY2008 1733 Distributed Correlative Power Control Schemes for Mobile Ad hoc Networks Using Directional Antennas Basel Alawieh, Student Member, IEEE, Chadi M. Assi, Member, IEEE, and Wessam Ajib, Member, IEEE Abstract—Medium access control (MAC) protocols simulta- neously integrating transmission power (TP) control with direc- tional antennas have the potential to enhance both energy savings and capacity throughput in wireless multihop Mobile Ad hoc NET- works (MANETs). In this paper, we present a model to calculate future interference in networks with directional antennas, and based on this model, we derive some relations that should exist between the required TP of RTS, CTS, DATA, and ACK frames for successful data packet delivery in MANETs based on the directional version of the IEEE 802.11 distributed coordination function. From these relations, we propose a distributed power control scheme. Furthermore, we show, via simulations, that the true potentials from the proposed control scheme cannot be shown due to the imperfection of the derived model. Based on these observations, we introduce another class of power control algo- rithm that instead deploys a prediction filter (Kalman or extended Kalman) to estimate future interference. Simulation experiments for different topologies are used to verify the significant through- put and energy gains that can be obtained by the proposed power control schemes. Index Terms—Directional antenna, interference, Kalman filter, Mobile Ad hoc NETwork (MANET), power control. I. I NTRODUCTION T HE RAPID evolution of mobile Internet technology has provided incentives for building efficient multihop ad hoc networks. Recent research activities have focused on the design of better physical layers, development of efficient medium access control (MAC) protocols, and use of directional anten- nas. Due to the great potential that directional antennas have shown in the cellular wireless area, it is expected that using directional antennas in a multihop wireless local area network (WLAN) environment could also lead to better performance in terms of higher data rates, reduced interference, and energy consumption. However, to take full advantage of these potential benefits, efficient MAC protocols that are directional antenna friendly need to be designed. A. IEEE 802.11 and Power Control The most popular MAC for WLAN is IEEE 802.11 [1], which is based on Carrier Sense Multiple Access with Manuscript received March 1, 2007; revised June 24, 2007 and August 18, 2007. The review of this paper was coordinated by Dr. E. Hossain. B. Alawieh and C. M. Assi are with Concordia University, Montréal, QC H3G 1M8, Canada (e-mail: b_alawi@encs.concordia.ca; assi@encs. concordia.ca). W. Ajib is with the Department of Computer Sciences, Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada (e-mail: ajib.wessam@uqam.ca). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TVT.2007.909264 Fig. 1. Power control and directional antenna merits. (a) Power control merits. (b) Directional antenna merits. Collision Avoidance using omnidirectional antenna. Request- to-send/clear-to-send (RTS/CTS) control messages are added as extensions to prevent packet collisions and solve the hidden terminal problem. In particular, the RTS/CTS control messages are used to reserve a transmission floor for data message transmission. Hence, nodes lying in the vicinity of the omni- directional transmission that hear the RTS or the CTS message defer their transmissions until the ongoing communication is complete. In IEEE 802.11, all packets (RTS/CTS/DATA/ACK) are sent with maximum power. It has been shown that this kind of handshake communication decreases spatial reuse and, thus, decreases capacity throughput and additionally yields unnecessary energy consumption [2]. To illustrate, consider the scenario in Fig. 1(a), where node A uses its maximum transmission power (TP) to send packets to node B, and nodes D and E will try to initiate a communication with nodes C and F, 0018-9545/$25.00 © 2008 IEEE