In industrial automation systems, the introduction of wireless networks as an extension of the existing wired networks is increasing. However, with the existing wireless technologies, it is impossible to guarantee this coexistence for those applications with strict real-time and reliability requirements such as Networked Control Systems (NCS) or Distributed Control Systems (DCS). The main problem lies in the design of the Medium Access Control (MAC) protocol, as this plays a key role in fulfilling real-time and deterministic requirements. Moreover, the integration of both networks is fundamental to provide a seamless coexistence guaranteeing the demanding requirements of these applications. So, in order to expand the wired network used in NCS to a wireless domain, a hybrid IEEE 802.3/IEEE 802.11 real-time TDMA-based MAC scheme is proposed in this paper. The proposed scheme can support the transmission of periodic real-time traffic and aperiodic real-time traffic in a deterministic way, together with best-effort (BE) traffic. Moreover, with the aim of increasing the reliability of the communication system, retransmission mechanisms are defined. The performance of these MAC schemes has been evaluated over Rayleigh fading channel through OMNeT++ simulator. Provided results show that the transmission of periodic real-time traffic is not affected by the transmission of aperiodic or BE traffic. Moreover, results show that the transmissions and retransmissions are adapted to tight control cycles.