臺灣博碩士論文加值系統

多重輸入多重輸出之正交分頻多工(multiple-input multiple-output orthogonal frequency-division multiplexing，MIMO-OFDM)通訊系統有著引人注目的傳輸技術，就是具有高資料傳輸率，所以MIMO-OFDM被應用在高效能的4G寬頻通訊系統上。但是和OFDM一樣有著主要的缺點就是傳輸訊號具有較高的峰值對平均功率比(peak-to-average power ratio，PAPR)。在本篇論文中，我們使用空頻區塊碼(space-frequency block coding，SFBC)，並應用在MIMO-OFDM系統上，提出新型的SFBC架構。新型的SFBC架構除了符合Alamouti所提出的transmit diversity之外，其在接收端combining scheme的部份只要稍作修正，即可符合Alamouti提出的combining scheme，不會增加運算複雜度。而我們藉由提出新型的SFBC架構來降低PAPR。針對2根傳送天線之間的訊號，將訊號等份分成幾個子區塊(subblocks)，每個子區塊可放置不同或者相同的SFBC架構，利用此法來產生多組訊號，並降低PAPR，我們稱為A方法和B方法，其中A方法使用4種SFBC架構，而B方法使用8種SFBC架構。經電腦模擬驗證，我們提出新型SFBC架構利用子區塊可放置不同或者相同SFBC架構的A方法和B方法，還有經過所有組合數統計的C方法，和Bar-Ness等作者提出的PII (Polyphase Interleaving and Inversion)比較，在子區塊分為 2、4和8時，且在CCDF為 機率下我們所提出的B方法較PII方法好約1dB、1.3dB和0.55dB；而C方法較PII方法好0.2 dB、0.7 dB和0.5 dB的縮減PAPR效果，並且適用於任何使用SFBC MIMO-OFDM之通訊系統。

An attractive transmission technique for high-data-rate communication systems is multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM). MIMO-OFDM has become a high performance transmission for 4G broadband wireless communications. However, like OFDM, one main disadvantage of MIMO-OFDM is the high peak-to-average power ratio (PAPR) of the transmitted signals. In this paper, we employ SFBC MIMO-OFDM system, and propose a novel SFBC scheme to reduce PAPR of the MIMO-OFDM transmit signals. The novel SFBC schemes conform to Alamouti SFBC scheme, and the corresponding combining are almost the same in the receiver. We partition data symbol into some subblocks that are taken to have the same sizes between two transmitted antennas, and we get more SFBC patterns to reduce the PAPR. We propose method A and method B; the method A uses 4 SFBC patterns, the method B uses 8 SFBC patterns. We also propose a PAPR reduction method, called method C, that use the best 4 SFBC patterns from the 8 designed SFBC patterns. Computer simulation results show that, compared with polyphase interleaving and inversion method, the proposed method B have better PAPR reduction performance of about 1dB, 1.3dB and 0.55dB for M = 2,4 and 8, respectively. Method C also has a advantage of PAPR reduction of about 0.2dB, 0.7dB and 0.5dB for M = 2,4 and 8, respectively.

目 錄
指導教授推薦書
口試委員會審定書
授權書 iii
誌謝 iv
摘要 v
Abstract vi
第一章 序論 1
1.1 引言 1
1.2 研究動機及目的 2
1.3 論文架構 3
第二章 OFDM基礎原理與訊號模型 4
2.1 OFDM歷史與演進 4
2.2 OFDM訊號模型 4
2.3 OFDM的循環字首 7
2.4 OFDM PAPR的問題 ….9
2.5 PAPR機率統計的描述………...10
第三章 SFBC/STBC MIMO-OFDM系統 12
3.1 MIMO技術 12
3.2 MIMO-OFDM系統……………………………….....13
3.3 Alamouti transmit diversity scheme 14
3.4 SFBC MIMO-OFDM系統介紹 16
3.5 STBC MIMO-OFDM系統介紹 16
第四章 MIMO-OFDM PAPR縮減技術 18
4.1 應用於STBC MIMO-OFDM系統的PAPR縮減技術 18
4.1.1 Concurrent Selective Mapping (concurrent SLM)方法 18
4.1.2 Cross Antenna Rotation and Inversion (CARI)方法 20
4.1.3 SLM with Subband Permutation方法 23
4.2 應用於SFBC MIMO-OFDM系統的PAPR縮減技術 25
4.2.1 Polyphase Interleaving and Inversion (PII)方法 25
4.2.2 PII with Generalized Complex Orthogonal Code 29
4.2.3 Clipping技術 30
4.3 其他的MIMO-OFDM PAPR縮減技術 34
4.3.1 Spatial Shift (SS)方法 33
4.3.2 Directed Selected Mapping (dSLM)方法 37
4.3.3 Two-Dimensional Permutation (TDM)方法 37
第五章 新型SFBC架構 40
5.1 PII方法在接收端的combining scheme 40
5.2 新型SFBC架構的combining scheme 41
5.3 降低PAPR的A方法、B方法和C方法 44
第六章 模擬結果與討論 49
6.1 PAPR模擬參數 49
6.2 PAPR比較 49
6.3 BER模擬參數 56
6.4 BER比較 56
第七章 結論 60
參考文獻 61

圖目錄
圖2.1 OFDM系統架構圖 5
圖2.2 多載波技術與OFDM技術比較圖 5
圖2.3 頻域上子載波正交圖 6
圖2.4 時域上子載波正交圖 7
圖2.5 ISI示意圖 8
圖2.6 ICI示意圖 8
圖2.7 具循環字首的OFDM 9
圖2.8 加入循環字首後的子載波示意圖 9
圖2.9 不同子載波數目之PAPR比較圖…………………………………………11
圖3.1 MIMO示意圖 13
圖3.2 MIMO-OFDM系統傳送端架構圖 14
圖3.3 MIMO-OFDM系統接收端架構圖 14
圖3.4 Alamouti transmit diversity scheme 15
圖4.1 concurrent SLM之示意圖 19
圖4.2 SS-CARI之示意圖 22
圖4.3 SLM with Subband Permutation之示意圖 24
圖4.4 PII方法之示意圖 28
圖4.5 SFBC transmitter for clipping 33
圖4.6 SFBC receiver for IAR method 34
圖4.7 subblock partitioning 35
圖4.8 SS方法之示意圖 36
圖4.9 TDP方法之示意圖 39
圖5.1 新型SFBC架構之示意圖 46
圖6.1 M = 2各種降低PAPR方法之比較圖 50
圖6.2 M = 4各種降低PAPR方法之比較圖 51
圖6.3 M = 8各種降低PAPR方法之比較圖 51
圖6.4 M = 2加入C方法的各種降低PAPR方法之比較圖 52
圖6.5 M = 4加入C方法的各種降低PAPR方法之比較圖 53
圖6.6 M = 8加入C方法的各種降低PAPR方法之比較圖 53
圖6.7 M = 2、V = 16的各種降低PAPR方法之比較圖 55
圖6.8 M = 4、V = 256的各種降低PAPR方法之比較圖 55
圖6.9 8種combining schemes和1對1天線之BER比較圖 57
圖6.10 M = 2各種降低PAPR方法之BER比較圖 57
圖6.11 M = 4各種降低PAPR方法之BER比較圖 58
圖6.12 M = 8各種降低PAPR方法之BER比較圖 58

表目錄
表5.1 PII方法的4種SFBC架構 40
表5.2 PII方法4種SFBC架構的combining架構 41
表5.3 8種形式的SFBC架構 41
表5.4 8種SFBC架構的combining schemes 43
表5.5 70組的PAPR dB值 47

[1] S. M. Alamouti,“A simple transmit diversity technique for wireless communication,”IEEE J. Select Areas Commun., vol. 16, no. 8, pp.1451-1458, Oct. 1998.
[2] K. F. Lee, and B. D. Williams, “A space-frequency coded transmitter diversity technique for OFDM systems,” in Proc. IEEE GLOBECOM, San Francisco, , CA, 2000. pp. 1473-1477
[3] S. H. Han, and J. H. Lee, “An overview of peak-to-average power ratio reduction techniques for multicarrier transmission,” IEEE Wireless Commun., vol. 12, pp. 56-65, Apr. 2005.
[4] Z. Latinović, and Y. Bar-Ness, “SFBC MIMO-OFDM peak-to-average power ratio reduction by Polyphase Interleaving and Inversion,” IEEE Commun. Lett., vol. 10, no. 4, pp. 266-268, Apr. 2006.
[5] Z. Wang and Y. Bar-Ness, “Peak-to-average power ratio reduction by Polyphase Interleaving and Inversion for SFBC MIMO-OFDM with generalized complex orthogonal code,” Inform. Sci. and Syst. 2006 40th Annu. Conference on, pp. 317-320, Mar. 2006.
[6] U. Kwon, D. Kim, K. Kim, and G. Im, “Amplitude clipping and iterative reconstruction of STBC/SFBC-OFDM signals,” IEEE Signal Process. Lett., vol. 14, no. 11, pp. 808-811, Nov. 2007
[7] R. R. Mosier, and R. G. Clabaugh, “Kineplex, a bandwidth efficient binary transmission systems,” IEEE Trans. Commun. , vol. 76, pp. 723-728, Jan. 1958.
[8] G. C. Porter, “Error distribution and diversity performance of a frequency differential PSK HF modem,” IEEE Trans. Commun., vol. COM-16, pp. 567-575, Aug. 1968.
[9] M. S. Zimmerman and A. L. Kirsch, “The AN/GSC-10 (KATHRYN) variable rate data modem for HF radio,” IEEE Trans. Commun., vol. COM-15, pp. 197-205, Apr. 1967.
[10] S. B. Weinstein and P. M. Ebert, “Data transmission by frequency-division multiplexing using the Discrete Fourier Transform”, IEEE Trans. Commun., vol. COM-19, no. 5, pp. 628-634, Oct. 1971.
[11] B. Hirosaki, “An analysis of automatic equalizers for orthogonally multiplexed QAM systems”, IEEE Trans. Commun., vol. COM-28, no. 1, pp. 73–83, Jan. 1980.
[12] M. Jiang, and L. Hanzo, “Multiuser MIMO-OFDM for next-generation wireless systems”, Proc. IEEE, vol. 95, no. 7, July 2007.
[13] L. G. Chen, PAPR reduction using nonlinear companding schemes with iterative receiver for OFDM systems, July 2007, pp. 1-45.
[14] J. Tellado, Multicarrier modulation with low PAPR: applications to DSL and wireless. Norwell, MA: Kluwer, 2000.
[15] R. van Nee and R. Prasad, OFDM for wireless multimedia communications, Artech House, 2000.
[16] Y. L. Lee, Y. H. You, W. G. Jeon, J. H. Paik, and H. K. Song, “Peak-to-average power ratio in MIMO-OFDM systems using selective mapping,” IEEE Commun. Lett., vol. 7, pp. 575-577, Dec. 2003
[17] M. Tan, Z. Latinović, and Y. Bar-Ness, “STBC MIMO-OFDM peak-to-average power ratio reduction by Cross-Antenna Rotation and Inversion,” IEEE Comm. Lett., vol. 9, no. 7, pp. 592-594, July 2005.
[18] B. J. A. Bassem, J. Slaheddine, and B. Ammar, “A PAPR reduction method for STBC MIMO-OFDM systems using SLM in combination with subband permutation,” Proc. Int. Conf. on Wireless and Mobile Commun. (ICWMC’07), Mar. 2007, pp. 88-88.
[19] T. C. W. Schenk, P. F. M. Smulders, and E. R. Fledderus,“Peak-to-average power reduction in space division multiplexing based OFDM systems through Spatial Shifting,”Electron. Lett., vol. 41, no.15, pp. 860-861, July 2005.
[20] R. F. H. Fischer and M. Hoch, ”Directed selected mapping for peak-to-average power ratio reduction in MIMO-OFDM,” Electro. Lett., vol. 24, no. 22, pp. 762-767, Oct. 2006.
[21] L. Wang and Y. Wang, “MIMO-OFDM peak-to-average power ratio reduction by Two-Dimensional Permutation,” Electron. Lett., vol. 43, no. 10, pp. 579-580, May 2007.
[22] V. Tarokh, H. Jafarkhani, and A. R. Calderbank, “Space-time block codes from orthogonal designs,”IEEE Trans. Inform. Theory, vol. 45, no. 5, July 1999.