Minimizing energy consumption is becoming more and more crucial in today's mobile terminals communications. Reducing its use pass necessarily by exploiting low power design techniques and by adopting novel energy-aware applications and protocols. The focus in this paper mainly concerns the Voice over IP over Wireless Local Area Network (VoWLAN) application, which is beyond doubt the most popular application in mobile terminals. The real-time nature of this application makes the conventional approaches inefficient, as they conserve energy by either: (i) switching the wireless device from the active mode to the sleep mode when no data is buffered for transmission or reception, which completely block the mobile terminal in the active mode (i.e. waste of energy), or (ii) forcing the switching to the sleep mode, which is clearly a detrimental behavior for such delay-constrained application. The idea of the proposed paper is to wisely determine the optimal schedule between the Sleep and Wakeup periods based on the application requirements. Hence, we propose in the following a quality of experience (QoE)-aware protocol, maximizing the sleep mode duration, for VoIP application. The performance of the proposed protocol is performed through computer simulation. The obtained results clearly demonstrate the superiority of the protocol in conserving energy while keeping the QoE at a desired level.