Resource Allocation Method for OFDM System to Transmit SVC over Frequency Selective Channel

摘要

Orthogonal frequency division multiplexing provides frequency diversity gain when assuming frequency selective channel which happens in most cases of wireless mobile communications. The frequency diversity can be utilized by considering data which requires unequal protection. Video data coded by scalable video coding method is an example. The video coding method encodes a certain picture period termed as group of pictures into a bit stream which can be divided into one or more decodable units. The unit is called as video layer. However the decodability of each video layer is dependent on existence of other video layers in the same bit stream. The dependency causes priority of the layer. This paper proposes a method to improve video transmission performance by adaptively providing radio resources according to the priority of the layers and also by controlling the number of the layers according to channel condition. The proposed method actives only useful subchannels and adaptively applies modulation level to the active subchannels. In the simulation, the proposed system showed 4 to 5 dB improvement in terms of channel quality, compared to a single carrier system.