Over the last decade, Wireless Sensor Network (WSN) has gained considerable attention in various real-time applications. Since WSN works with battery operated nodes, utilization and optimization of node energy is one the primary challenge. For effectively handling and controlling the energy consumption problem in WSN, cross-layer optimization is one of the important methods. For a researcher working in the domain of WSN, energy constraint is a huge challenge to deal with. MAC layer is one of the major source of energy consumption so, an innovative energy efficient MAC protocol using a cross-layer approach in the heterogeneous wireless sensor network is proposed. In this protocol, first, packet retransmission by reducing packet loss is addressed by considering buffer space, channel state and remaining energy. Second, the synchronization scheme for a global schedule is implemented by deliberating adaptive listening using the length of the transmission queue. Finally, sleep time issue is worked out to reduce energy consumption. In this scenario, the nodes will be in sleep mode unless it has some packets to send or receive. The proposed protocol is implemented in Network Simulation (NS2). The simulation results show that the heterogeneous wireless network performs better in terms of energy consumption, packet data rate and energy buffer state while implementing through the proposed protocol.