In mobile radio systems, the bandwidth of spread
spectrum signals for CDMA system is very wide. If
the bandwidth exceeds the coherence bandwidth of
the channel, the signal is seriously distorted by
the multiple propagation paths. The available
bandwidth is divided into a lot of small parts in
Multi-carrier-CDMA system. Selecting the number
of subcarriers according to the environment of
channel will make the bandwidth of spread
spectrum signals smaller than the coherence
bandwidth of channel. And then the system can
overcome the question of multiple propagation
paths.
The performance of Multi-carrier CDMA system
is sensitive to frequency offset. Frequency
offset results from Doppler shift due to mobile
movement, as well as from a mismatch between the
carrier frequency of local oscillators at the
transmitter and receiver. Consequently, the
subcarriers¡¦ orthogonality are lost, causing
Inter-carrier Interference (ICI). The
interference of other subcarriers will make the
error of estimated channel coefficients. Effect
of frequency offset will lower the performance of
the combing detector that needing channel
estimated.
In this thesis, we propose a method to
correct the frequency offset. Using the relation
of two continuous received signals to estimate
the frequency and compensate it. We will analysis
and compare this method in different condition.
Simulation results will demonstrate the
performance of this proposed method.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0623101-184903 |
| Date | 23 June 2001 |
| Creators | Chen, Yue-Shuan |
| Contributors | Chao-Hung Chen, Shiunn-Jang Chern, Ching-Tai Chiang, Jin-Nan Li |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0623101-184903 |
| Rights | not_available, Copyright information available at source archive |
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