WCDMA智慧型天線下相關性空時寬頻通道之塑模與模擬

Modeling and Simulation of Correlated Space-Time Wideband Channel with Application to WCDMA Smart Antenna System

黃彥儒(Yan Ru Hwang)

指導教授 ： 黃正光博士

元智大學/工程學院/電機工程學系/碩士(2002年)

摘要

WCDMA是第三代行動通訊系統中，普遍所採用的規格，其上鏈路實體通道訊號產生的過程，分別要經過兩層不同作用的展頻碼，第一層主要是用來區分各種不同傳輸速率的服務，而第二層則是用來區分不同用戶的身份，因此透過這兩層展頻碼的作用，使WCDMA比昔日窄頻的IS-95 CDMA系統，預留了許多的可以變動的彈性和優點，包括可使用以智慧型天線為基礎的接收機或採用干擾消除技術以增進系統性能及容量。
往昔的通道模型，並沒有將通道的各種性質，整合至一個完整的通道模型中，吾人特提出一所謂細胞式『三多』『三展』衰減通道模型(Cellular Triple-multiplicity Triple-spread Fading Channel Model),簡稱CM3S3FC，整合了下列多樣的通道特點：(1)多使用者分佈的情形，(2)多根陣列天線之空間幾何特性，(3)多路徑衰減的特性，(4)衰減訊號之PDF及PSD特性，(5)散射物質分佈的空間特性，最後並利用一向量通道模擬器( Vector Channel Simulator )，將上述各種通道特性的接收訊號模擬產生出來。
在以天線陣列解調WCDMA上鏈路訊號時，為了要解決多用戶干擾( MAI )的問題，便設計了以波束成型為基礎的接收機架構，吾人更進一步的推演出干擾消除多用戶接收機，以增進接收機的性能，此外，也可以以傳統空間分集技術為基礎的接收機，來解調WCDMA上鏈路的訊號，吾人透過電腦模擬實驗，來比較基於這兩大類設計基礎的接收機，其在不同用戶狀況及空時通道條件下，性能的差異處。

關鍵字

WCDMA ； 智慧型天線 ； 相關性 ； 寬頻時空通道

並列摘要

One of the most promising approaches to the third generation (3G) cellular systems is to combine a Wideband CDMA (WCDMA) air interface with the fixed network of GSM. For the uplink of WCDMA, two kinds of spreading codes, one is used to select different transmission rates and the other is used to distinguish different users. Therefore, WCDMA inherits more flexible ability and benefits than the conventional narrow band CDMA system that is IS-95 system. Besides, WCDMA can also together use the smart antenna or the MAI cancellation technique to increase the system performance and system capacity.
In this thesis, a novel vector channel model called Cellular Triple-multiplicity Triple-spread Fading Channel (CM3S3FC) Model with all kinds of channel characteristics is investigated. It consists of: (1) the distribution of users, (2) the geographic property of the antenna array, (3) the fading property of the multi-path transmission, (4) the character PDF and PSD of the fading signals, and (5) the distribution of the scatters. Herein, we will use a vector channel simulator to generate the received signals to meet all these properties.
Based on the above novel channel model, we adopt two receiver structure for the WCDMA uplink signals. First, we induce a beam-forming based receiver structure to overcome the MAI (multiple access interference). Then induce the extended receiver structure with the MAI cancellation to increase the receiver performance. Then, we propose the receiver structure with spatial diversity technique to demodulate the WCDMA uplink signals. Finally, some computer simulations demonstrate the performance comparisons of these two kinds of receiver structures in different environment conditions.

並列關鍵字

WCDMA ； Smart Antenna ； Correlated ； Wideband Space-Time Channel

參考文獻

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