Performance Comparison of Multi-user Detection and Multi-Antenna Technique for Multi-user DS-CDMA UWB System
Date Issued
2005
Date
2005
Author(s)
Hu, Wen-Feng
DOI
en-US
Abstract
In this thesis, we adopt Multi-User Detection (MUD) and multi-antenna technique in a DS-CDMA UWB system. Then, based on the simulation results, we compare the improvement in system performance between MUD and multi-antenna technique.
During wireless communication, the channel delay spread will cause considerable Inter Symbol Interference (ISI) and hence equalizer or channel estimator has to be employed. Besides, we can utilize multipath energy to increase Signal to Noise Ratio (SNR). The use of a RAKE receiver is one possible method.
Due to the lower correlation of users’ spreading code, we apply them to obtain the weightings of the typical MUD receiver. If the receiver doesn’t know all users’ spreading code, blind adaptive MUD receiver is applied, which has the lower complexity and can track the fast-varying channel.
The multi-antenna technique can be classified into SIMO、MISO and MIMO systems. The spatial and time diversity combining techniques are employed to improve the system performance in SIMO and MISO systems.
On the other hand, the antenna effect is crucial in the UWB system. Therefore, we compare the antenna effect between the DS-CDMA UWB system and MB-OFDM UWB system.
Subjects
超寬頻
直接序列分碼多工
耙式接收器
線性等化器
線性通道偵測器
時間分集
路徑分集
最小平均誤差平方法
多用戶偵測
可適性猜測技術
子空間追蹤
最小輸出能量法
多天線系統
多輸入多輸出
最大比例結合
空時編碼
正交分頻多工
Ultra-Wideband (UWB)
Direct-Sequence Code-Division Multiple Access (DS-CDMA)
RAKE receiver
Linear Equalizer (LE)
Linear channel estimator
time diversity
path diversity
Minimum Mean-Square Error (MMSE)
Multi-use Detection (MUD)
blind adaptive technique
subspace tracking
Minimum Output Energy (MOE)
multi-antenna
MIMO
Maximum Ratio Combining (MRC)
Space Time Block Code (STBC)
Orthogonal Frequency Division Multiplexing (OFDM)
Type
thesis
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