| Summary: | 碩士 === 國立高雄師範大學 === 光電與通訊工程學系 === 101 === In this thesis, we study a simple precoding technique, which employs short block codes to create coding as well as diversity advantages across the subcarriers of an OFDM system over Rayleigh fading. Such a signaling mechanism, termed the constellation index precoding, maps each data symbol of the original constellation into a set of coded symbols selected from the expanded constellation by means of the well-defined algorithm. Since the coded symbols of a codeword are interleaved and then modulated each by an individually subcarrier of OFDM, the diversity gain can be achieved. Based on the statistics of the received signals, we present a maximum-likelihood coherent receiver for the considered system. The union bound of the error probability is defined as the code value figure, which can be used to search for high-performance codes. We conduct the computer simulations to verify the tightness of the union bounds for the error probability, and make a performance comparison among the proposed and the existing precoding techniques found in related literature. It is shown that the system provides a distinguished performance improvement when compared with an uncoded OFDM system.
|
|---|
