This paper proposes a channel monitor-based unequal error protection scheme using a dynamic OFDM subcarrier assignment technique for broadband video transmission systems in frequency selective fading environments. In the proposed system, to achieve stable regeneration of the received video, subcarriers with relatively high channel gain are assigned to the high priority data (HPD) in the MPEG data. To further guarantee a required transmission quality of the HPD, the proposed system also employs subcarrier transmission power control with delay profile information (DPI) feedback-type channel estimation technique. Computer simulation confirms that the proposed technique is effective in preventing quality degradation with about 20 dB lower transmission power than the conventional systems in frequency selective fading environments.

A peak power reduction technique is proposed for subcarrier transmit power control applied orthogonal frequency division multiplexing (OFDM) system. In the proposed system, carrier-holes are created by applying a partial non-power allocation (PNPA) technique in which no transmit power is allocated to subcarriers with lower received Eb/N0, and the amplitude and phase adjusted peak reduction subcarrier (PRS) is iteratively inserted in the non-power allocated subcarrier so as to suppress peak power. Computer simulation confirms that the proposed scheme can reduce peak power by 3.6 dB while keeping the same information bit-rate with conventional subcarrier transmit power control applied OFDM systems.