ALCA: A New Scheme for Power Control on 802.11 Ad Hoc Networks

— This paper presents the ALCA (Asymmetric Link Collision Avoidance) protocol. ALCA was designed to deal with a known deficiency of the Basic Scheme [1] for power control in 802.11 ad hoc networks, which occurs when links become asymmetrical as a result of power control. In this mechanism, which is the model for many other power control algorithms, RTS and CTS control frames are sent at the maximum power level, while the DATA and ACK frames are sent at the minimum power level required for communication. In RF communication, there is a carrier-sensing zone around each transmitter, inside which other neighboring nodes are able to sense a carrier on the transmission medium, but cannot correctly receive a frame. As a result, these terminals are not able to access the transmission duration field present in RTS and CTS frames in order to avoid collisions. When transmission power is reduced for DATA frame transmission, these terminals may no longer sense the data carrier. Thus, if any one...

• Type: Conference
• Year: 2005
• Where: WOWMOM
• Authors: Alexandre Andrade Pires, José Ferreira de Rezende, Carlos de M. Cordeiro
• Keywords: Power Control, Power Level, Transmission Duration, WOWMOM 2005