Applications of Complementary Codes in QPSK Communication Systems
| Autor: | Chi-Hui Chang, 張啟慧 |
|---|---|
| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 In multi-carrier transmission system such as the Orthogonal Frequency Division System (OFDM) it may generate a large peak-to-average power (PAP) ratio when the consisting sub-carriers add up coherently. A large PAP ratio will generate certain problems in the design of the transmission system such as the increase of the complexity of the analog-to-digital (A/D) and digital-to-analog (D/A) converters and the reduction of the efficiency of the RF power amplifier. In this paper we study and employ the complementary code keying (CCK) scheme to generate a code set and use this code set to modulate the QPSK digital waveform so that the system’s PAP ratio will be limited below certain level. Two code sets, namely the complementary sequences and the Walsh-Hadamard code, are considered. The decoding scheme associated with each encoding set is also derived. In order to study the effectiveness of our derived encoding and decoding schemes we use simulation technique to evaluate the system bit error rate performance when a sequence of QPSK data are transmitted through an additive white Gaussian noise environment. From the simulation result it reveals that the system is working in the way as the system is designed by using either code set. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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