This paper presents a robust frame boundary synchronization technique for In-Band Full-Duplex (IBFD) communication systems, that employ Orthogonal Frequency Division Multiplexing (OFDM). First, we describe the system model of a wireless link consisting of a full-duplex (FD) base station, that is receiving a signal from a remote station while transmitting simultaneously on the same frequency. Received signal impairments such as carrier frequency offset (CFO), sampling time offset (STO), channel response and channel delay are modeled. We then identify two common scenarios that can occur and cause the correlation base frame edge detection to fail. We present a novel and robust frame start detection technique taking into account STO, CFO and channel estimation effects. Performance of the proposed technique is quantified using a simulation framework and confirmed using experimental measurements. The proposed robust synchronization method demonstrated successful frame edge detection with up to 65 ppm carrier frequency offset versus a loss of 40% of the frames without using the proposed method.