臺灣博碩士論文加值系統

在本篇論文中，吾人考慮在GSM/DCS-1800無線行動通訊系中使用智慧型天線陣列技術來解決通道衰減(fading)，多重路徑(multipath)以及共通道干擾(CCI)的影響，並且增進系統容量。首先不同於GSM下非線性GMSK調變訊號之模型，吾人利用一階近似AMP(Amplitude Modulation Pulse)合成GMSK之線性訊號模型，並使用反轉(de-rotation)技巧配合上分數間距取樣，提出GMSK訊號之SIMO線性近似模型，也產生濾波器組(Filter Bank)新型接收機結構。吾人也針對GSM系統之空間介面建立空間-時間通道數學模型，並利用ML最佳化準則，發展出空間-時間濾波器組Viterbi等化器，(Space-Time Filter Bank Viterbi,ST-FBVA)，其與傳統GMSK下Viterbi最大的不同點在於不用再去考慮CPM(Continue Phase Modulation)信號所帶來的瞬時"相位"狀態問題，因此降低了接收機的複雜度。
其次吾人尋求更簡單及低複雜度的空間-時間接收機，使用MMSE準則，提出空間-時間可適性濾波器組DFE(Space-Time Adaptive Filter Bank Decision Feedback Equalizer,ST-AFB-DFE)，並探討相關之通道估測問題，隨後更在ST-AFB-DFE下建立MIMO(Multi-Input Multi-Output)系統模型以研究GSM系統之多使用者偵測(multiuser detection)，以此大幅擴充系統容量。
在GSM真實系統通常考慮的三種不同通道模型，即山區、丘陵(Hilly Terrain,HT)，鄉村(Rural Area,RA)，及城市(Typical Urban,TU)，經由電腦實驗模擬得知，吾人顯示出原本在單天線接收所遭受的困頓情況，並證實出加入空間-時間處理技術後可顯著改進系統效能及容量。而且即使是採用低複雜度的新型接收機，其效能也達到近似最佳化接收機。

In this thesis, we consider using smart antenna array technique to combat Channel fading, multipath and Co-Channel Interference(CCI) in GSM/DCS-1800 mobile communication system,thereby increasing both performance and capacity .In contrast with the conventional nonlinear GMSK signal for GSM, we approximate the GMSK signal in terms of a first-order linear AMP(Amplitude Modulation Pulse) model. Then we exploit de-rotation skill and fractionally spaced structure to construct an SIMO linearized GMSK model, and develop various multichannel or filter Bank receiver structures. Then the whole structure is extended to the resulting space-time channel through using smart antenna array for diversity reception. Under this framework, various space-time GSM receivers are derived and investigated .
First, by using the ML optimization criterion, we develop a Space-Time Filter Bank Viterbi equalizer(ST-FBVA), which is simpler than the conventional GMSK Viterbi receiver in that it doesn't need to care the instant phase status in the original nonlinear CPM(Continue Phase Modulation) signal model, therefore reducing the number of states and computationl complexity.
Second, the MMSE criterion is exploited to derive simpler and low complexity spatial-temporal receiver structure. This results in the Space-Time Adaptive Filter Bank Decision Feedback Equalizer (ST-AFB-DFE) which can be regarded as a good tradeoff between the complexity and performance. Besides, we also investigate the problem of channel estimation. To increase the capacity of GSM system, a possible MIMO space-time channel model and associated multiuser detection scheme are also presented.
With extensive computer simulations, we investigate the above ST receivers under three typical GSM channel models, including hilly terrain (HT), rural area (RA),and typical urban(TU). It is demonstrated that by using the antenna array for reception, the space-time processing techniques can significantly improve the system performance as well as system capacity, as compared to the receiver with only single antenna.

中文摘要 I
英文摘要 II
誌謝 IV
目錄 V
第一章 簡介 1
第二章 數位傳輸技術及空間-時間處理法 4
2.1數位通訊系統之離散時間通道模型 4
2.2 GMSK調變系統 5
2.3可適性智慧型天線陣列 10
2.3.1 時間處理法 10
2.3.2 空間處理法 11
2.3.3 空間-時間處理法 12
第三章 GSM/DCS1800智慧型天線陣列之整合空間-時間處理技術 15
3.1 GSM系統規格 15
3.1.1傳統GMSK等化器 15
3.1.2 通道估測及窗口 16
3.1.3 估測訊號產生器 17
3.1.4 增量運算 17
3.2 GMSK信號線性近似模型(AMP 表示法) 21
3.3 GMSK信號下SIMO線性近似模型 24
3.4 智慧型天線陣列之空間-時間處理技術 28
3.4.1 智慧型天線陣列 28
3.4.2 GSM系統空間-時間濾波器組Viterbi等化器(ST-FBVA) 29
3.4.3 ST-FBVA 通道估測器 33
3.5 GSM系統可適性濾波器組DFE 36
3.5.1 ST-MMSE 準則 36
3.5.2 可適性濾波器組DFE(AFB-DFE) 37
3.5.3 空間-時間可適性濾波器組DFE(ST-AFB-DFE) 41
3.5.4 EDFE(Erasure Decision Feedback Equalizer) 44
3.5.5 重複訓練模式(re-training mode) 46
3.6 多使用者偵測(Multiuser detection) 48
第四章 電腦實驗結果 54
4.1 GSM/DCS-1800 系統參數 54
4.2 通道模型 54
4.3 電腦模擬實驗 57
4.3.1 模擬GMSK信號 57
4.3.2 GMSK Viterbi 等化器 59
4.3.3 GMSK FBVA 等化器 64
4.3.4 GMSK AFB-DFE 66
4.3.5 AFB-DFE下MIMO系統 73
4.3.6 共通道干擾(Co-Channel Interference) 77
第五章 結論 84
參考文獻 86

[1] Bernard. Sklar, "Rayleigh fading channels in mobile digital communication systems Part 1: Characterization," IEEE Commun. Mag.,Jul. 1997.
[2] M. D. Yacoub, Foundations of mobile radio engineering. CRC, 1993.
[3] J. Paulraj, and B. Papadias, "Space-time processing for wireless communications," IEEE Signal Processing Mag., pp. 49-83, Nov. 1997.
[4] J. H. Winters, "Signal acquisition and tracking with adaptive arrays in the digital mobile radio system IS-54 with flat fading," IEEE Trans. Veh. Technol., Vol. 42, pp. 377-384, Nov. 1993.
[5] J. H. Winters, J. S. Salz, and R. D. Girlin, "The impact of antenna diversity on the capacity of wireless communication systems," IEEE Trans. Commun., Vol.42, pp. 1740-1751, 1994.
[6] J. H. Winters, "Smart antennas for wireless systems," IEEE Personal Commun., pp.23-27, Feb. 1998.
[7] L. C. Godara, "Applications of antenna arrays to mobile communications, Part 1: Performance improvement, feasibility, and system considerations," Proc. IEEE, pp.1029-1060, Jun. 1997.
[8] S. Haykin, Adaptive filter theory. Prentice-Hall, 1996.
[9] J. G. Proakis, Digital communications. 3rd edition, McGraw-Hill, 1995.
[10] S. Haykin, Communication systems. 3rd edition, John-Wiley & Sons. 1994.
[11] Marco Chiani, "Introducing erasures in decision-feedback equalization to reduce error propagation," IEEE Trans. Commun., Vol.45, pp. 757-760, Jul. 1997.
[12] R.D. Gitlin, J.F. Hayes, and S.B. Weinstein, Data communications principles. Plenum, 1992.
[13] W. C. Jakes, Microwave mobile communications. New York: Wiley, pp.66-70, 1974.
[14] J.-T.Chen, A. Paulraj, and U.Reddy,"Multichannel Maximum-Likelihood Sequence Estimation (MLSE) Equalizer for GSM Using a Parametric Channel Model,"IEEE Trans.Commun.,Vol.47, No1, pp.53-63,Jan.1999.
[15] R. Stell, Mobile Radio Communications. New York: IEEE Press,1992
[16] P. A. Laurent, "Exact and approximate construction of digital phase modulations by superposition of amplitude modulated pulses (AMP),"IEEE Trans .Commum.,Vol.COM-34,pp. 150-160,Feb.1986.
[17] B. A. Bjerke, J. G. Proakis., M. K. Lee and Z. Zoonar,"A Comparison of Decision Feedback Equalization and Data Directed Estimation Techniques for GSM System,"IEEE 6th International Conference.Vol. 1 pp.84-88 1997.
[18] G. E. Bottomley and K. Jamal,"Adaptive arrays and MLSE equalization," in Proc. 45th IEEE Vehicular Technology Conf. pp. 50-54.July 1995.
[19] P.Jung and P.Baier,"On the representation of CPM signals by linear superposition of impulses in the baseband domain,"IEEE J. Select. Areas Commun.,Vol. 10, pp. 1236-1242, Oct. 1992.
[20] G.D. Forney,"Maximum likelihood sequence eseimateion of digital sequences in the presence of intersymbol interfierence," IEEE Trans. Inform. Theory, Vol.18,No. 5,pp. 363-378,1972.
[21] G. Li and Z. Ding,"A semi-blind channel identification method for GSM receiver,"Proc. 1998 ICASSP,Vol.6, pp.3389-3392 pn. 1834,Seattle,1998.
[22] G. K. Kaleh, "Simple Coherent Receivers for Partial Response Continuous Phase Modulation",IEEE Journal on Selected Areas in Communications, Vol.7,pp.1427-1436,Dec.1989.
[23] Asha Mehrotra,"GSM System Engineering,"Artech House,Inc.,Boston,London
[24] J.Salz,"Optimum Mean Square Decision Feedback Equalization,"Bell System Tech.J.,Vol. 53,No.8,pp. 1341-1373,Oct.1973.
[25] D.D. Falconer and F. R. Magee, Jr., "Adaptive Channel Memory Truncation for Maximum Likelihood Sequence Estimation,"Bell System Tech.J.,Vol. 52,No.9, pp.1541-1562, Nov.1973.
[26] Siavash M. Alamouti, "A Simple Transmit Diversity Technique for Wireless Communications," IEEE J. Select. Areas Commun.,Vol.16,No.8 ,pp.1451-1458, Oct.1998 .
[27] Xiaodong Wang and H. Vincent Poor, "Robust Adaptive Array for Wireless Communications," IEEE J. Select. Areas Commun.,Vol. 16,No. 8,pp 1352-1366, Oct. 1998.
[28] L. C. Godara, "Applications of antenna arrays to mobile communications, Part II: Beam-Forming and Direction-of-Arrival Considerations," Proc. IEEE,Vol. 85 pp.1193-1245,Aug. 1997.
[29] G .L. Stuber, "Principles of Mobile Communication," Kluwer Academic , Boston,Dordrecht , London.