| Summary: | 碩士 === 國立交通大學 === 電信工程系 === 91 === Due to its high-data rate transmission capability, multi-carrier code division multiple access (MC-CDMA) systems have attained increasing significance in wireless communications. The multi-user interference is one of the main factors limiting the system capacity of a MC-CDMA system. While the conventional linear minimum mean square error detector (LMMSE) has good performance, its computational complexity is high. The parallel interference cancellation (PIC) detector can have good performance; however, it may have incorrect decisions in the early stages. In this thesis, we propose new methods to overcome these problems. Using the multi-carrier channel characteristics, we propose a new LMMSE method such that the number of the combining weights can be significantly reduced. To reduce decision errors in the PIC detector, we propose a partial PIC approach in which partial cancellation factors (PCF) are introduced to control the interference cancellation level. Optimal PCFs are derived using a MMSE criterion. Simulations show that the proposed LMMSE method can have the similar performance as conventional ones. The proposed partial PIC detector can outperform the full PIC detector.
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