Academic Journal
Adaptive DS-CDMA multiuser detection for time variant frequency selective Rayleigh fading channel
| العنوان: | Adaptive DS-CDMA multiuser detection for time variant frequency selective Rayleigh fading channel |
|---|---|
| المؤلفون: | Tang, Xin |
| المصدر: | Dissertations |
| بيانات النشر: | Digital Commons @ NJIT |
| سنة النشر: | 2002 |
| المجموعة: | Digital Commons @ New Jersey Institute of Technology (NJIT) |
| مصطلحات موضوعية: | Code Division Multiple Access (CDMA), Multi-user detection, Time-variant channel, Channel estimation, Rayleigh fading, Electrical and Electronics |
| الوصف: | The current digital wireless mobile system such as IS-95, which is based on direct sequence Code Division Multiple Access (DS-CDMA) technology, will not be able to meet the growing demands for multimedia service due to low information exchanging rate. Its capacity is also limited by multiple accessed interference (MAI) signals. This work focuses on the development of adaptive algorithms for multiuser detection (MUD) and interference suppression for wideband direct sequence code division multiple access (DS-CDMA) systems over time-variant frequency selective fading channels. In addition, channel acquisition and delay estimation techniques are developed to combat the uncertainty introduced by the wireless propagation channel. This work emphasizes fast and simple techniques that can meet practical needs for high data rate signal detection. Most existing literature is not suitable for the large delay spread in wideband systems due to high computational/ hardware complexity. A de-biasing decorrelator is developed whose computational complexity is greatly reduced without sacrificing performance. An adaptive bootstrap symbolbased signal separator is also proposed for a time-variant channel. These detectors achieve MUD for asynchronous, large delay spread, fading channels without training sequences. To achieve high data rate communication, a finite impulse response (FIR) filter based detector is presented for M-ary QAM modulated signals in a multipath Rayleigh fading channel. It is shown that the proposed detector provides a stable performance for QAM signal detection with unknown fading and phase shift. It is also shown that this detector can be easily extended to the reception of any M-ary quadrature modulated signal. A minimum variance decorrelating (MVD) receiver with adaptive channel estimator is presented in this dissertation. It provides comparable performance to a linear MMSE receiver even in a deep fading environment and can be implemented blindly. Using the MVD receiver as a building-block, an adaptive ... |
| نوع الوثيقة: | text |
| وصف الملف: | application/pdf |
| اللغة: | unknown |
| Relation: | https://digitalcommons.njit.edu/dissertations/542; https://digitalcommons.njit.edu/cgi/viewcontent.cgi?article=1597&context=dissertations |
| الاتاحة: | https://digitalcommons.njit.edu/dissertations/542 https://digitalcommons.njit.edu/cgi/viewcontent.cgi?article=1597&context=dissertations |
| رقم الانضمام: | edsbas.4AA3F426 |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |