| 摘要: | 在本論文中，我們提出一種結合時域、頻域、空域之寬頻/分時雙工/多天線/多調-分碼多工接取系統之整合架構收發機，考慮多使用者及外來干擾於下鏈傳送之通訊情形，並以旁波辦消除器(GSC)及最小變異無失真響應(MVDR)之波束構成技術來抵抗其他使用者所造成的多重接收干擾(MAI)。本系統架構中，發射訊號同時產生於頻域及空域中以達成平行傳送資料之高速下鏈能力，其次，因為在分時雙工的系統中，通道增益可以藉由上鏈接收獲得，此時將其運用於下鏈發射訊號上進行空-頻之通道預先處理。再者，為增加系統之容量與速率，吾人利用多個展頻碼產生器，同時傳送多個通道預先處理過的訊號。然後，藉由反快速傅利葉轉換與保護區間來達成寬頻多載波平行傳送高速資料。最後，多天線同時發射訊號，使用戶台獲得空間上分集增益。經由上述之發射處理後，在接收端部分，吾人使用陣列間格半波長之智慧型天線接收來強調某方向之抗干擾之能力，以電腦模擬結果與傳統單一天線接收機做比較，並針對不同的環境加以分析。 In the thesis, we propose an integrated architecture of wideband, time division duplex (TDD), multiple input-smart antenna output (MIS*O), and multitone-code division multiple access (MT-CDMA) transceiver, which is advantageous characteristics of frequency, time, spatial domain. We consider multiuser and multiple access interference (MAI) scenarios in downlink communication and combat MAI of other users by generalized sidelobe canceller (GSC) and minimum variance distortionless response (MVDR) beamforming techniques. Firstly, in our proposed system architecture, transmission signals are generated simultaneously in frequency and spatial domains to reach high speed downlink capability through parallel data transmission. Secondly, due to the availability of channel gains by means of uplink receiving in a TDD system, it is therefore applied in the downlink transmission signals to proceed spatial-frequency channel preprocessing. Hereafter, in order to increase system capacity and speed, we take advantage of multiple spread spectrum code generators, and transmit multiple channel preprocessed signals simultaneously. Then, the goal of wideband, multi-carrier, parallel transmission of high speed of data is reached by means of inverse fast Fourier transform and guard band intervals. Finally, the diversity gain in spatial domain is obtained in subscriber through simultaneous multi-antenna transmission signals. After through the transmission processing as aforementioned, in the subscriber side, we can also utilize a smart antenna with many antenna elements spaced within half wavelength, different from conventional single antenna, to receive transmitting signals from base station to enhance anti-jamming capability in specific directions. |
