OCC-CDMA system design for wireless communications
high data rate is important because of factors such as a higher demand in
multimedia capability of mobile devices and the exponentially increasing number of
subscribers. Wireless communications in today’s technology have many limitations
due to channel imperfections, which result in less than satisfactory speed of
transmission and less reliability. Moreover, bandwidth, one of the most the precious
resources of all communication schemes, has been reaching the limit established
either by the spectrum governing bodies such as the FCC in the U.S. or by
technological shortcomings. This means that increasing the number of users is
extremely difficult. Researchers have been inventing and developing many
techniques to overcome such limitations. Good examples are real-time channel
estimation and compensation, new modulation techniques, efficient coding
algorithms and novel multiple-access techniques.
This thesis presents a new CDMA modem (modulator-demodulator) which
achieves a higher bandwidth efficiency in a multiple user scenario than conventional
CDMA-based systems and attains low BER performance through the application of
orthogonal-complementary coded CDMA (OCC-CDMA) and non-conventional QAM.
The OCC-CDMA itself has the advantages of less multiple access interference (MAI) and capability of transmitting the maximum of 1 bit per spreading chip, which
is impossible to achieve with conventional CDMA. By utilizing such unique
properties of OCC-CDMA, high information transmission rates with acceptable BER
performance can be achieved.
Advisor:Magaña, Mario E.
School:Oregon State University
School Location:USA - Oregon
Source Type:Master's Thesis
Keywords:code division multiple access wireless communication systems design and construction signal processing digital techniques
Date of Publication:07/12/2004