Pre-filtering Technique for MAI Cancellation in Multi-Code MC-CDMA Systemsin Multi-Code MC-CDMA SystemsPre-filtering Technique for MAI Cancellation

• Main Authors: Cherng-Chang Yu, 顏正宗
• Other Authors: Jyh-Horng Wen
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/05867809951727157005

碩士 === 國立暨南國際大學 === 通訊工程研究所 === 95 === Abstract Multi-carrier (MC) multiplexing and code division multiple access (CDMA) are two common signaling technologies in wireless communications. In MC-CDMA system, instead of applying spreading sequences in time domain, we can apply them in frequency domain. The resulting spectrum of each sub-carrier can satisfy the orthogonality condition with the minimum frequency separation. In a (synchronous) down-link mobile radio communication channel, we can use Hadamard Walsh codes as an optimum orthogonal set. In down-link, the performance of single-user detectors becomes worse due to multiple access interference (MAI) disturbances. In this thesis, we consider the use of transmitter filters to reduce the MAI in Multi-code (MC) MC-CDMA systems over a multi-path fading channel. To satisfy different quality of service (QoS), we can assign different power for every sub-carrier by least-square solution. In down-link, total virtual user signals are transmitted simultaneously. The QoS requirement can be satisfied. Besides, the computational complexity is easy to be reduced by using pre-filtering technique at the same time.