使用連續干擾消除技術之3GPP寬頻分碼多重進接上鏈接收機之研討及在數位訊號處理器上的實現

Abstract

寬頻分碼多重進接是最重要的第三代行動通訊系統之一，它提供高速的資料傳輸，達到每秒3.84百萬片(chip)資料。由於多個使用者同時被服務，因此可使用多使用者偵測技術來大幅提昇傳輸品質。在各種多使用者偵測技術中，連續干擾消除技術是一個直覺並常見的方法，且在實現上較可行。在本論文中，我們在Innovative Integration公司的Quatro6x DSP板上實現一個使用連續干擾消除技術的寬頻分碼多重進接接收機。 首先，我們回顧寬頻分碼多重進接的實體層(physical layer)上鏈傳輸，以及它的接收技術。接著簡介Quatro6x DSP板的架構與操作，並詳述使用PCI介面在DSP和主電腦之間的溝通方法。然後，我們提出在DSP實現上的架構和效能，以及完成在多種通道狀態下的模擬，包括在固定和Rayleigh淡化下的通道。 若只實現rake接收機在DSP上，在所有情況下我們皆可達到即時(real-time)的處理。至於使用連續干擾消除技術的接收機，在四條路徑的情況下，速度落後即時的要求約三倍。未來可再精煉DSP程式，以及在架構上改變以達到更佳的DSP效能。

UMTS/W-CDMA has become one of the most important third-generation (3G) cellular systems, providing high data rate transmission at a rate of 3.84M chips per second. Since many users are being served at the same time, multiuser detection technique can be employed to effect significant improvement of transmission performance. Among the multiuser detection methods, successive interference cancellation (SIC) is an intuitive and common approach, and more easily realizable in implementation. In this thesis, we implement an SIC receiver for W-CDMA on Innovative Integration company’s Quatro6x DSP board. First, we review the physical layer uplink transmission of W-CDMA, and discuss the associated receiving techniques. Secondly, we introduce the structure and operation of the Quatro6x DSP board, and detail the method of communication between the DSP and the host PC via the PCI interface. Thirdly, we describe the structures, the DSP implementation and the resulting performance. In addition, simulations are performed under several channel conditions, including static and Rayleigh fading channels. We can achieve real-time processing in all conditions if merely rake receiver is implemented on DSP. If employing the SIC receiver, we fall behind real-time requirements by about three times in 4-path condition. We may further refine the DSP code and modify the structure in the future to attain better efficiency of DSP.