Abstract
This paper presents an energy efficient H.264 video transmission over wireless ad hoc networks based on an adaptive IEEE 802.11e EDCA (enhanced distributed channel access) mechanism. The standard IEEE 802.11e EDCA mechanism provides only service priority differentiation for time bound applications over ad hoc networks. However, this standard does not provide adaptation mechanism to respond to the time varying network link status. Furthermore, the critical issues in energy efficient transmission have not been addressed under EDCA mechanism. In this research we develop a new adaptive scheme to adjust the Contention Window (CW) after each transmission attempt based on current network link status. This adaptation scheme is also integrated with energy efficient FHSS (BFSK) scheme in order to save the energy consumption during the transmission. An analytical model of Energy efficient estimator (E3 metric) is developed to support the selection of modulation scheme. We also carry out NS-2 based simulation, in combination with E3 model, to evaluate the proposed scheme in comparison with standard IEEE 802.11e EDCA. Based on extensive simulation with H.264/AVC video over the proposed AEDCA and the standard EDCA, we demonstrate that the proposed AEDCA with Energy efficient BFSK scheme outperforms the standard IEEE 802.11e EDCA with an improved video quality as well as reduced energy dissipation.