In this work, we introduce an enhanced cooperative medium access control protocol which merges a cooperative protocol with a packet correction technique at the link layer level. The proposed protocol aims to improve data communication reliability of in-home broadband power line communication (PLC) systems. More specifically, the cooperative protocol performs relayed retransmissions according to the relay availability, for assisting data communication between nodes source and destination. In case a data packet retransmission fails, the node destination uses corrupted copies from the transmitted and the retransmitted packets from nodes source and relay, respectively, which are stored in its buffer, in order to detect and correct the erroneous bits. The performance evaluation of the proposed protocol is accomplished by simulations based on measured power line channel frequency responses and an additive noise model of in-home electric power grids, which cover broadband applications and bit error pattern at the link layer level. The physical layer makes use of orthogonal frequency division multiplexing and orthogonal frequency division multiple access schemes. Furthermore, a comparison among PLC systems using the proposed protocol to others using only a cooperative protocol and without any cooperative protocol at link layer is analyzed. Numerical results show that improvements in terms of data communication reliability can be achieved in comparison with previous protocols under the presence of background and impulsive noises.