APPARATUS AND METHOD FOR PILOT INSERTION AND ARRANGEMENT FOR HIERARCHICAL MODULATION IN OFDM TRANSMISSION SYSTEM

摘要

Provided is a hierarchical modulation apparatus capable of improving transmission performance of an OFDM transmission system through pilot insertion and a pilot array structure. In the OFDM transmission system having a base layer channel encoder, an enhancement layer channel encoder, and hierarchical modulator, the hierarchical modulation apparatus includes: a pilot insertion unit inserting pilots into an encoded enhancement layer signal sequence output from the enhancement layer encoder, the pilots having a correlation with a base layer signal sequence corresponding to the same sub-carriers as those of the encoded enhancement layer signal sequence; and a pilot size controller controlling sizes of the pilots received from the hierarchical modulator. Accordingly, by applying the hierarchical modulation to an existing DMB system, it is possible to minimize influence of channels to an existing service and increase a data transmission rate.