臺灣博碩士論文加值系統

為了讓無線通訊系統更能應用於實際生活，低複雜度高效能的系統是極需被開發。從之前的文獻研究得知最佳化與低複雜度難以共存，兩者只能擇其一。很幸運地，分解圖(Factor Graph)的方法看起來是有希望的。經由有效地交換含有統計特性的資訊在分解圖中，最佳化與低複雜度是可以共存的。本論文闡述如何使用分解圖的方法來解決三個無線通訊系統的問題：1)以接收信號強度為基礎的室內位置估測；2) 以信號傳遞時間為基礎的室外位置估測；3)一個無線通訊系統盲通道估測與資料偵測。
傳統以接收信號強度為基礎的室內位置估測不是因為模型不吻合而導致不準確，就是沒有考慮測量誤差的統計特性，要不然就是太複雜而無法應用。為了簡化演算法，局部線性化的技術被發展出來，它是建立在功率衰減輪廓圖(Power Decay Profile)曲面上的局部線性，而這個功率衰減輪廓圖是由訓練的指數接收信號強度測量資料所組成的，並且是從個別的無線發射台(Access Point)所蒐集到的；為了確保較好的準確性，測量誤差的統計特性與測量資料的可靠度被引用於分解圖中。實驗數據顯示：所提出演算法不僅具低複雜度，而且可達到近似的最大可能性(Maximum Likelihood)解答，而這個最大可能性解答是建構在訓練的接收信號強度測量資料之基礎上。
大部份現存以信號傳遞時間為基礎的室外位置估測演算法忽略了測量資料的可靠度，因此估測準確性受到限制。為了改善無線用戶在直視(Line-of-sight)與非直視(Nonline-of-sight)環境下的估測準確性，測量資料的可靠度觀念被引用。為了更進一步改善這個準確性，各種複雜的追蹤技術被提出。這裡為了降低追蹤技術之計算複雜度，便利用分散式的處理來實現卡門濾波器(KalmanFilter)。實驗數據顯示：結合測量資料的可靠度與分散式的處理，這演算法不僅可達到高的準確性，而且具低複雜度。
因為分解圖的方法已經被證明成功的解決複雜位置估測的問題，所以這有效的方法也可以被應用在無線通訊系統盲通道估測與資料偵測上。在盲的接收器中，簡單的差分資料偵測機制被選用。為了避免系統效率降低，複雜的通道估測技術被應用來追蹤通道的變化。所以，用分解圖為基礎的盲通道估測與資料偵測的演算法便發展出來。而電腦模擬顯示：針對快速時變的無線通道，所提出的演算法是強健的。

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
LIST OF FIGURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
CHAPTER
1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Indoor RSS-based Position Location Estimation . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Outdoor TOA-based Location Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 The Blind Channel Estimation and Data Detection for a Wireless
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 The Thesis Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. A NOVEL INDOOR RSS-BASED POSITION LOCATION
ALGORITHM USING FACTOR GRAPHS . . . . . . . . . . . . . . . . . . . . . 5
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Indoor PL System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Hyperplane Approximation and Local Constraint . . . . . . . . . . . . . . . . . . . . 12
2.4 The Proposed Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4.1 Factor Graph Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4.2 Soft-Information Calculation and Passing . . . . . . . . . . . . . . . . . . . . 15
2.5 Performance Bound and System Complexity . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5.1 Performance Bound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5.2 System Complexity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.6 Simulation Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.7 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3. A FACTOR-GRAPH-BASED TOA LOCATION ESTIMATOR
INCORPORATING THE RELIABILITY
INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.2 System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.3 Data Reliability and NLOS Mitigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.3.1 Data Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.3.2 NLOS Mitigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.4 The Proposed Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.4.1 Factor Graph, Reliability and Negotiation Rule . . . . . . . . . . . . . . . . 40
3.4.2 Factor Graph Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.4.3 Soft-Information Calculation and Passing . . . . . . . . . . . . . . . . . . . . . 46
3.5 ML Bound and Complexity Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.6 Simulation Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.7 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4. FACTOR-GRAPH-BASED ITERATIVE BLIND CHANNEL
ESTIMATION AND DATA DETECTION FOR A
MIMO-OFDM SYSTEM WITH I.I.D. WIRELESS
CHANNELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.2 System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.2.1 Transmit Coding Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.2.2 Channel Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.3 The Proposed Blind Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.3.1 Iterative Channel Estimation and Channel Equalization . . . . . . . . 70
4.3.2 Iterative DSTBC Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
4.4 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
4.5 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
5. CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
APPENDIX: THE CONSTRUCTION OF EMULATED
MEASUREMENT DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

[1] J. Caffery, Wireless Location in CDMA Cellular Radio Systems. Kluwer Academic
Publishers, 2000.
[2] K. Pahlavan, X. Li, and J. P. Makela, “Indoor geolocation science and technology,”
IEEE Commun. Mag, vol. 40, pp. 112-118, Feb. 2002.
[3] A. H. Sayed, A. Tarighat, and N. Kajehnouri, “Network-based wireless location,”
IEEE Signal Processing Mag, vol. 22, pp. 24-40, July 2005.
[4] L. Cong and W. Zhang, “Hybrid TDOA/AOA mobile user location for wideband
CDMA celluar systems,” IEEE Trans. Wireless Commun., vol. 1, pp. 439-447,
July 2002.
[5] P. Bahl and V. N. Padmanabhan, “RADAR: An in-building RF-based user location
and tracking system ,” Proc. IEEE INFOCOM 2000, vol. 2, Mar. 2000,
pp. 775-784.
[6] L. M. Ni, Y. Liu, Y. C. Lau, and A. P. Patil, “LANDMARC: Indoor location
sensing using active RFID ,” PerCom’03, Mar. 2003, pp. 407-415.
[7] N. Patwari, A. O. Hero, III, M. Perkins, N. S. Correal, and R. J. O’Dea, “Relative
location estimation in wireless sensor networks,” IEEE Trans. Signal Processing,
vol. 51, pp. 2137-2148, Aug. 2003.
[8] G. Sun, J. Chen, W. Guo, and K. J. R. Liu, “Signal processing techniques in
network-aided positioning,” IEEE Signal Processing Mag, vol. 22, pp. 12-23, July
2005.
[9] R. J. Drost and A. C. Singer, “Factor-graph algorithms for equalization,”
IEEE Trans. Signal processing, vol. 55, no. 5, pp. 2052-2065, May, 2007.
[10] F. R. Kschischang, B. J. Frey, and H. A. Loeliger, “Factor graphs and the sumproduct
algorithm,” IEEE Trans. Inform. Theory, vol. 47, pp. 498-519, Feb.
2001.
[11] J. C. Chen, Y. C. Wang, M. S. Maa, and J.T. Chen, “Network-side mobile
position location using factor graphs,” IEEE Trans. Wireless Commun., vol. 5,
No. 10, pp. 2696-2704, Oct. 2006.
[12] H. -A. Loeliger, J. Dauwels, J. Hu, S. Korl, L. Ping, and F. R. Kschischang,
“The factor graph approach to model-based signal processing,” Proceedings of
the IEEE, vol. 95, no.6, pp. 1295-1322, June 2007.
[13] G. Lindfield and J. Penny, Numerical Methods Using MATLAB. Ellis Horwood
Limitd, 1995.
[14] C. L. Wang, Y. S. Chiou, and S. C. Yeh, “A indoor location method based on
wireless local area networhs,” in Proc. IEEE CCNC-2005, Jan. 2005.
[15] C. L. Wang, Y. S. Chiou, and S. C. Yeh, “A location algorithm based on radio
propagation modeling for indoor wireless local area networhs,” in Proc. IEEE
VTC2005-Spring, May 2005.
[16] C. L. Wang, Y. S. Chiou, “An adaptive positioning method based on radio
propagation modeling for indoor WLANs,” in Proc. IEEE VTC2006-Spring, May
2006.
[17] http://www.linksys.com
[18] T. S. Rappaport, Wireless Communication: Principles and Practice. Englewood
Cliffs, NJ:Prentice-Hall, 1996.
[19] J. Caffery and G. Stuber,“Overview of radiolocation in CDMA cellular systems,”
IEEE Commun. Mag., vol. 36, pp. 38-45, Apr. 1998.
[20] Q. Bi, G. L. Zysman, and H. Menkes, “Wireless mobile communications at the
start of the 21st century,” IEEE Commun. Mag., vol. 39, no. 1, pp. 110-116, Jan.
2001.
[21] Y. Zhao, “Standardization of mobile phone positioning for 3G systems,” IEEE
Commun. Mag., vol. 40, no. 7, pp. 108-116, July 2002.
[22] Y. Qi and H. Kobayashi, “On relation among time delay and signal strength
based geolocation methods,” IEEE GLOBECOM., pp. 4079-4083, 2003.
[23] W. H. Foy, “Position location solutions by Taylor-Series estimation,” IEEE
Trans. Aerop. Electron. Syst., vol. 12, no. 2, pp. 187-193, Mar. 1976.
[24] J. Caffery, “A new approach to the geometry of TOA location,” in Proc. IEEE
Vehicular Technology Conference., vol. 4, pp. 1943-1949, Sept. 2000.
[25] M. I. Silventoinen and T. Rantalainen, “Mobile station emergency locating in
GSM,” in Proc. IEEE Personal Wireless Communications Conference., pp. 232-
238, 1996.
[26] M. P. Wylie and J. Holtzman, “The non-line of sight problem in mobile location
estimation,” in Proc. IEEE Universal Personal Wireless Communications
Conference., vol. 2, pp. 827-831, 1996.
[27] B. L. Le, K. Ahmed, and H. Tsuji, “Mobile location estimator with NLOS mitigation
using Kalman filtering,” in Proc. IEEE Wireless Communications and
Networking Conference., vol. 3, pp. 1969-1973, 2003.
[28] J. F. Liao and B. S. Chen, “Robust mobile location estimator with NLOS mitigation
using interacting multiple mode algorithm,” IEEE Trans. Wireless Commun.,
vol. 5, No. 11, pp. 3002-3006, Nov. 2006.
[29] Y. Qi, H. Kobayashi, and H. Suda, “Analysis of wireless geolocation in a nonline-
of-sight environment,” IEEE Trans. Wireless Commun., vol. 5, No. 3, pp.
672-681, Mar. 2006.
[30] S. AI-Jazzar, J. Caffery, and H. R. You, “Scattering-model-based methods for
TOA location in NLOS environments,” IEEE Trans. Vehicular Technology., vol.
56, No. 2, pp. 583-593, Mar. 2007.
[31] M. Hellebrandt, R. Mather, and M. Scheibenbogen, “Estimating position and
velocity of mobiles in a cellular radio network,” IEEE Trans. Vehicular Technology.,
vol. 46, No. 1, pp. 65-71, Feb. 1997.
[32] M. Hellebrandt and R. Mather, “Location tracking of mobiles in cellular radio
networks,” IEEE Trans. Vehicular Technology., vol. 48, No. 5, pp. 1558-1562,
Sept. 1999.
[33] T. Liu, P. Bahl, and I. Chlamtac, “Mobility modeling, location tracking, and trajectory
prediction in wireless ATM networks,” IEEE J. Select. Areas Commun.,
vol. 16, No. 6, pp. 922-936, Aug. 1998.
[34] C. L. Wang, Y. W. Hong, and Y. S. Dai, “A decentralized positioning method for
wireless sensor networks based on weighted interpolation,” in Proc. IEEE ICC
2007, Glasgow, Scotland, June 2007, pp. 3167-3172.
[35] S. M. Kay, Fundamentals of statistical Signal Processing Estimation Theory.
Englewood Cliffs, NJ : Prentice-Hall, 1993.
[36] L. J. Cimini Jr., “Analysis and simulation of a digital mobile channel using
orthogonal frequency division multiplexing,” IEEE Trans. Commun., vol. COM-
33, pp. 665-675, July 1985.
[37] IEEE Std 802.11a-1999, “Part 11: Wireless LAN Medium Access Control (MAC)
and Physical Layer (PHY) Specifications : High-speed Physical Layer in the 5
GHZ Band,” September 1999.
[38] IEEE Std 802.11g-2003, “Part 11: Wireless LAN Medium Access Control (MAC)
and Physical Layer (PHY) Specifications -Amendment 4: Further Higher Data
Rate Extension in the 2.4 GHZ Band,” June 2003.
[39] IEEE Std 802.15.3-2003, “Part 15.3: Wireless Medium Access Control (MAC)
and Physical Layer (PHY) Specifications for High Rate Wireless Personal Area
Networks (WPANs),” June 2003.
[40] IEEE Std 802.16-2004, “Part 16: Air interface for Fixed Broadband Wireless
Access Systems,” June 2004.
[41] S. M. Alamouti, “A simple transmitter diversity scheme for wireless communication,”
IEEE J. Select. Areas Commun., vol. 16, pp. 1451-1458, Oct. 1998.
[42] V. Tarokh, H. Jafarkhani, and A. R. Calderbank, “Space-time block codes from
orthogonal design,” IEEE Trans. Infom. Theory, vol. 45, pp. 1456-1467, July
1999.
[43] I. E. Teltar, “Capacity of multi-antenna Gaussian channels,” Eur. Trans.
Telecommun., vol. 10, pp. 585-595,Nov. 1999.
[44] V. Tarokh, A. Naguib, N. Seshadri, and A. R. Calderbank, “Space-time codes for
high data rate wireless communication: Performance criteria in the presence of
channel estimation errors, mobility, and multiple paths,” IEEE Trans. Commun.,
vol. 47, pp. 199-207, Feb 1999.
[45] G. G. Raleigh and J. M. Cioffi, “Spatio-temporal coding for wireless communication,”
IEEE Trans. Commun., vol. 46, No. 3, pp. 357-366, Mar. 1998.
[46] H Bolcskei, D. Gesbert, and A. J. Paulraj, “On the capcity of OFDM-based
spatial multiplexing systems,” IEEE Trans. Commun., vol. 50, pp. 225-234, Feb.
2002.
[47] C. K. Wen, Y. C. Wang, and J. T. Chen, “An adaptive spatio-temporal coding
scheme for indoor wireless communication,” IEEE J. Select. Areas Commun.,
vol. 21, pp. 161-170, Feb. 2003.
[48] V. Tarokh and H. Jafarkhani, “A differential detection scheme for transmit diversity,”
IEEE J. Select. Areas Commun., vol. 18, pp. 1169-1174, July 2000.
[49] B. L. Hughes, “Differential space-time modulation,” IEEE Trans. Infom. Theory
, vol. 46, pp. 2567-2578, Nov. 2000.
[50] B. M. Hochwald and W. Sweldens, “Differential unitary space-time modulation,”
IEEE Trans. Commun., vol. 48, pp. 2041-2052, Dec. 2000.
[51] H. J. Su and E. Geraniotis, “Low-complexity joint channel estimation and decoding
for pilot symbol-assisted modulation and multiple differential detection
systems with correlated Rayleigh fading,” IEEE Trans. Commun., vol. 50, pp.
249-261, Feb. 2002.
[52] Z. Liu, X. Ma, and G. B. Giannakis, “Space-time coding and Kalman filter for
time-selective fading channels,” IEEE Trans. Commun., vol. 50, pp. 183-186,
Feb. 2002.
[53] C. Cozzo and B. L. Hughes, “An adaptive receiver for space-time trellis codes
based on per-survivor processing,” IEEE Trans. Commun., vol. 50, pp. 1213-
1216, Aug. 2002.
[54] C. Cozzo and B. L. Hughes, “Joint channel estimation and data detection in
space-time communications,” IEEE Trans. Commun., vol. 51, pp. 1266-1270,
Aug. 2003.
[55] P. Hoeher and J. Lodge, ““Turbo DPSK”: Iterative differential PSK demodulation
and channel decoding,” IEEE Trans. Commun., vol. 47, pp. 837-843, June
1999.
[56] A. V. Nguyen and M. A. Ingran, “Iterative demodulation and decoding of differential
space-time block codes,” in Proc. IEEE VTC 2000-Fall, Boston, MA,
Sept. 24-28, 2000, pp. 2394-2400.
[57] C. S. Maa, C. T. Huang, Y. C. Wang, and J. T. Chen, “Blind joint channel
estimation and signal decoding for systems with time-varying Rayleigh-fading
channel,” in Proc. IEEE VTC 2003-Spring, Jeju, Korea, Apr. 22-25, 2003, pp.
2575-2578.
[58] L. R. Bahl, J. Cocke, F. Jelinek, and J. Raviv, “Optima decoding of linear codes
for minimizing symbol error rate,” IEEE Trans. Inform. Theory, vol. IT-20, pp.
284-287, Mar. 1974.
[59] Y. Li, N. Seshadri, and S. Ariyavisitakul, “Channel estimation for OFDM systems
with transmitter diversity in mobile wireless networks,” IEEE J. Select.
Areas Commun., vol.17, pp. 1233-1243, July 1999.
[60] B. Lu, X.Wang, and Y. Li, “Iterative receivers for space-time block coded OFDM
systems in dispersive fading channel,” IEEE Trans. Wireless Commun., vol. 1,
pp. 213-225, Feb. 2002.
[61] H. B¨olcskei, R. W. Health Jr., and A. J. Paulraj, “Blind channel identification
and equalization in OFDM-based multiantenna systems,” IEEE Trans. Signal
Processing, vol. 50, pp. 96-109, Jan. 2002.
[62] M. K. Oh, Y. H. Kwon, J. H. Park, and D. J. Park, “Blind iterative channel and
LPDC decoding for OFDM systems,” in Proc. IEEE VTC 2005-Spring, vol. 1,
30 May-1, June 2005, pp. 514-517.
[63] W. C. Jakes, Microwave Mobile Communication. Piscataway, NJ : IEEE Press,
1994.