Abstract: An adaptive rate control is proposed to improve Transmission Control Protocol (TCP) performance in the Home Area Networks (HANs) in smart grid. The HAN has heterogeneous feature and adopts Power Line Communications (PLC) and Wireless Local Area Network (WLAN) technologies. The proposed method exploits the communications mechanism of WLAN to improve the PLC link utilization. The Heuristic Dynamic Programming (HDP) technique is employed to obtain the optimal rate control policy. The bottleneck link capacity is estimated by neural network training. The sending rate of TCP data packet is adapted according to the long-term quality of service (QoS) of applications. Simulation results illustrate that the proposed method effectively filters out the negative impact from the impulse noise in PLC channel and outperforms the existing TCP.