| Author | Supachai Ruangsuthinarupap |
| Call Number | AIT Thesis no.TC-03-17 |
| Subject(s) | Code division multiple access
Multiplexing
|
| Note | A thesis submitted in partial fulfillment of the requirements for the
degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. TC-03-17 |
| Abstract | MC-CDMA is a combination technique of Orthogonal Frequency Division
Multiplexing (OFDM) and Code Division Multiple Access (CDMA). MC-CDMA has
several advantages such as, high rate data transmission, high bandwidth efficiency,
frequency diversity and interference reduction. The main drawback is high Peak to
Average Power Ratio (PAPR). Therefore, PAPR reduction methods are researched
extensively.
In this thesis, the effect of spreading sequences on PAPR by using three different
Walsh Hadamard code allocations have been studied. The result shows that PAPR
variation depends on the way the Walsh sequences are allocated to different users
especially for a small number of active users. A code selection method is introduced for
PAPR reduction. However, the achieved PAPR reduction by this technique is
insignificant for large number of active users. To reduce PAPR further, PAPR reduction
by combining selected mapping and selected spreading code is proposed. From the
simulation results, it is observed that PAPR can be reduced significantly at a cost of
increased system complexity proportional to the number of different phase sequences.
The BER performances for multipath fading of three systems, the original system, the
proposed system, and PTS are almost the same. Finally, four orthogonal sets of sequences
namely, Walsh Hadamard sequences, Golay complementary sequences, Orthogonal Gold
sequences, and Shapiro-Rudin sequences, are employed for spreading to study PAPR
characteristic with different number of active users. The simulation result shows that
Golay complementary sequences offer best PAPR reduction gain among the four types of
sequences. |
| Year | 2003 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. TC-03-17 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Ahmed, Kazi M. ; |
| Examination Committee(s) | Erke, Tapio J. ;Teerapat Sanguankotchakorn; |
| Scholarship Donor(s) | TOT Corporation Public Company Limited; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2003 |
