A Study on Improving Performance of Pre-Post-RAKE Combining in UWB-IR System

The purpose of this study is to analyze and improve performance of pre-post-RAKE combining in UWB-IR system. In UWB-IR system, it is easy and effective to improve communication quality by means of the path-diversity techniques such as RAKE combining. However, combining many paths requires large amount of calculations and this leads to the increase of the hardware complexity. This complexity may spoil the advantages of UWB-IR system in hardware implementation. Therefore, this research has focused on the division of RAKE combining to the transmitter and the receiver using Pre-Post-RAKE to improve this complexity problem and to maintain high quality communication. As seen in the result, there are some good pre-post combinations based on system parameters and an accuracy of channel estimation. Especially it is shown that the case of using channel estimation over 10 symbols is enough to achieve the good BER performance. Moreover, the results show that IPI must be taken care. The results also show that complex channel estimation scheme and other complex combining scheme that make the UWB-IR system complex are not always necessary