In this thesis, we investigate a wireless communications system with distributed transmit antennas. Under such system scenario, the received signal has multiple carrier frequency offsets (CFOs) since each transmitter has its own oscillator, leading to serious inter-carrier interference (ICI) at the receiver end. Therefore, an ICI self-cancellation scheme is proposed in this thesis, where two different relay nodes use different sub-carriers. When the signals from different relay nodes are combined at the destination node, the ICI self-cancellation can be achieved.
In addition, the quality of the received signal can be further improved if the residual CFO can be properly compensated. Traditionally, the medium value of the various CFOs is taken for compensation because of its simplicity. However, a medium value does not result in the optimal performance. In this thesis, a close form expression of optimal CFO is derived to maximize the average signal to interference power ratio. It is shown that the optimal CFO compensation is a function of channel state and individual CFOs.
Simulation experiments are conducted to investigate the performance of the proposed scheme. It is shown that the system bit error rate can be substantially improved when the CFO is less than 0.3 subcarrier spacing.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0825110-151604 |
| Date | 25 August 2010 |
| Creators | Chou, Yi-chuan |
| Contributors | Yu-Te Su, Chih-Peng Li, Chin-Liang Wang, Ding-Bing Lin, Char-Dir Chung |
| 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-0825110-151604 |
| Rights | campus_withheld, Copyright information available at source archive |
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