As a method to realize a high-speed communication in home network, the power-line communication (PLC) technique is known. A problem of the PLC is that leakage radiation interferes to existing systems. When OFDM is used in PLC system, the leakage radiation is not sufficiently reduced, even if the subcarriers corresponding to frequency-band of the existing system are never used, because the signal is not strictly band-limited. To solve this problem, each subcarrier must be band-limited. In this paper, we apply the OQAM based multi-carrier transmission (OQAM-MCT) to high-speed PLC system, where each subcarrier is individually band-limited. We also propose a pilot-symbol sequence for frequency offset estimation, symbol-timing detection and channel estimation in the OQAM-MCT system. In this method, the pilot signal-sequence consists of the succession of the same data symbol. Computer simulation results show that the OQAM-MCT system achieves both good transmission rate performance and low out-of-band radiation in the PLC channels. It is also shown that the proposed pilot-sequence improves frequency offset estimation, symbol-timing detection and channel estimation performance as compared with the case of using pseudo-noise sequence.