Signalakquisition in DS-Spreizspektrum-Systemen und ihre Anwendung auf den 3GPP-FDD-Mobilfunkstandard

Robust signal acquisition is an important task in DS-SS receivers. The objective of the acquisition is to coarsely estimate the signal parameters such that the succeeding parameter tracking algorithms can be initialized. In particular, acquisition is needed to coarsely synchronize the receiver to the timing and frequency of the received signal. For this purpose mainly data aided and feedforward algorithms are applied. Using the maximum likelihood (ML) criterion, an estimator for the joint estimation of receive timing and frequency offset can be derived which determines the maximum of the Likelihood function over the whole parameter uncertainty region. Due to its high complexity the ML synchronizer is difficult to implement for practical applications. Hence, complexity reduced algorithms need to be derived. This thesis gives a systematic survey of acquisition algorithms and of performance analysis methods for analyzing such algorithms under mobile radio propagation conditions. The exploitation of multiple observations is investigated in order to improve the acquisition performance in terms of false alarm rate and acquisition time. In particular, optimal and suboptimal combining schemes for a fixed observation interval as well as sequential utilization of successive observations resulting in a variable observation length are analyzed. Another possibility to make the signal acquisition more efficient in terms of the acquisition time is to use multi stage acquisition algorithms. One class of those algorithms are the well known multiple dwell algorithms. A different approach is to design acquisition procedures in which the information about the unknown parameters is distributed among several stages such that each stage has to cope with a smaller uncertainty region in comparison to the overall parameter uncertainty. Analysis of multi stage algorithms followed by an extensive discussion of the 3GPP FDD downlink acquisition procedure as an example of a multi stage procedure with distributed information conclude the work.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Technische Universität Dresden

Year

2004

Author dc:creator

• Zoch, André

Contributors dc:contributor

• Fettweis, Gerhard
• Jondral, Friedrich
• Finger, Adolf

• 3GPP-FDD
• Mobilfunk
• PN-Code-Akquisition
• Signalakquisition
• Synchronisation
• UMTS
• WCDMA
• Mobile Communications
• PN code acquisition
• Signal acquisition
• Synchronization