M C L C.
M C L C.
THU T NG VI T T T.
DANH M C NH V .
L I NÓI Đ U.
Ch ng 1ươ ................................................................................................................. x
T NG QUAN V K THU T MIMO-OFDM VÀ
H TH NG THÔNG TIN DI Đ NG. ................................................................... x
1.1. Gi i thi u. ......................................................................................................... x
1.2. S l c v l ch s phát tri n trong thông tin di đ ng.ơ ượ ................................ x
1.2.1. Gi i thi u chung. ....................................................................................... x
1.2.2. Nh ng t n t i khó khăn v k thu t trong lĩnh v c thông tin di đ ng.
............................................................................................................................ xiii
1.3. Môi tr ng tuy n trong thông tin di đ ng.ườ ế ............................................ xiii
1.3.1. Méo biên đ . ............................................................................................ xv
1.3.1.1. Mô hình fading Rayleigh. ......................................................................... xv
1.3.1.2. Mô hình fading Rician. ............................................................................. xv
1.3.1.3. Th ngc a fading. .............................................................................. xvi
1.3.2. Suy hao đ ng truy n.ườ ........................................................................ xviii
1.3.3. Tr i tr trong hi n t ng đa đ ng. ượ ườ .................................................. xix
1.3.4. T p âm tr ng Gauss. .............................................................................. xix
1.3.5. Hi n t ng Doppler. ượ ............................................................................... xx
1.4. T ng quan v k thu t MIMO-OFDM. ...................................................... xxi
1.4.1. Đ nh nghĩa và ki ni m. ...................................................................... xxii
1.4.2. K thu t MIMO-OFDM. ...................................................................... xxii
1.5. K t lu n ch ng.ế ươ ....................................................................................... xxiii
Đ ÁN T T NGHI P.
M C L C.
Ch ng 2 ươ ........................................................................................................ xxiv
K THU T OFDM. ........................................................................................... xxiv
2.1. Gi i thi u. .................................................................................................... xxiv
2.2. Khái ni m chung. .......................................................................................... xxv
2.2.1. H th ng đ n sóng mang. ơ .................................................................... xxv
2.2.2. H th ng đa sóng mang. ....................................................................... xxvi
2.2.3. Tín hi u tr c giao. ............................................................................... xxvii
2.3. S đ h th ng OFDM băng c s .ơ ơ ........................................................ xxviii
2.4. C s toán h c.ơ ............................................................................................. xxx
2.4.1. Tr c giao. ............................................................................................... xxx
2.4.2. IFFT/FFT. ............................................................................................... xxx
2.5. Các k thu t c b n trong OFDM. ơ ........................................................... xxxi
2.5.1. S đ đi u ch /Gi i đi u ch .ơ ế ế ........................................................... xxxi
2.5.2. hoá kênh. ...................................................................................... xxxiii
2.5.3. S p x p. ế .............................................................................................. xxxiv
2.5.4. K thu t IFFT/FFT trong OFDM. .................................................... xxxiv
2.5.5. Ti n t l p CP. ................................................................................... xxxvi
2.5.6. c l ng kênh.Ướ ượ ............................................................................... xxxviii
2.5.6.1. Khái ni m. ........................................................................................ xxxviii
2.5.6.2. c l ng kênh trong mi n t n s . Ướ ượ ..................................................... xli
2.5.6.3. c l ng kênh trong mi n th i gian.Ướ ượ ................................................. xlii
2.6. So sánh đ ph c t p gi a k thu t OFDM v i đi u ch đ n ng mang. ế ơ
.............................................................................................................................. xliii
2.7. K t lu n ch ng.ế ươ .......................................................................................... xlv
Ch ng 3ươ ............................................................................................................... 46
K THU T MIMO. .............................................................................................. 46
Đ ÁN T T NGHI P.
M C L C.
3.1. Gi i thi u. ....................................................................................................... 46
3.1.1. u đi m c a k thu t MIMO.Ư .............................................................. 46
3.1.2. Khuy t đi m c a h th ng MIMO.ế ...................................................... 47
3.2. Dung l ng kênh truy n c a h th ng MIMO.ượ ......................................... 47
3.3. S l c pn t p.ơ ượ ........................................................................................... 47
3.3.1. Phân t p th i gian. .................................................................................. 48
3.3.2. Phân t p t n s . ...................................................................................... 49
3.3.3. Phân t p không gian. ............................................................................... 49
3.3.4. Các ph ng pp k t h p phân t p.ươ ế .................................................... 50
3.3.4.1. B t h p theo ki u quét và l a ch n (SC). .......................................... 50
3.3.4.2. B t h p cùng đ l i (EGC). ................................................................ 51
3.3.4.3. B t h p v i t s t i đa (MRC). .......................................................... 52
3.4. Mã hóa không gian_th i gian. ........................................................................ 54
3.4.1.a kh i không gian th i gian (Space time block Codes). ............... 55
3.4.1.1. Mãa Alamouti. ..................................................................................... 56
3.4.1.2 Orthogonal STBC Tarokh cho s anten phát b t k ............................... 57
3.5. K t lu n ch ng.ế ươ ........................................................................................... 60
Ch ng 4ươ ............................................................................................................... 61
K THU T MIMO-OFDM. ................................................................................. 61
4.1. Gi i thi u. ....................................................................................................... 61
4.2. Mô t t ng quan v h th ng MIMO_OFDM. ........................................... 61
4.2.1. MIMO-OFDM Tx. .................................................................................... 62
4.2.2. MIMO_OFDM Rx. ................................................................................... 62
4.2.3. C u trúc c a khung (frame) c a h th ng MIMO-OFDM. ................ 63
4.3. Phân tích h th ng MIMO-OFDM. .............................................................. 64
4.3.1. hình h th ng MIMO-OFDM. ......................................................... 64
4.3.2. Space-Time Block-Coded OFDM. ............................................................ 65
Đ ÁN T T NGHI P.
M C L C.
4.3.2.1. H th ng STBC-OFDM. ......................................................................... 65
4.3.2.2. B phát STBC-OFDM. ............................................................................ 66
4.3.2.3. B thu STBC-OFDM. .............................................................................. 67
4.4. K t lu n ch ng.ế ươ ........................................................................................... 70
Ch ng 5ươ ............................................................................................................... 71
MÔ PH NG H TH NG MIMO-OFDM
VÀ ĐÁNH GIÁ CH T L NG H TH NG. ƯỢ ................................................... 71
5.1. Gi i thi u n i dung mô ph ng. ..................................................................... 71
5.2. Các thông s ph ng. ................................................................................. 71
5.2.1. H th ng OFDM. .................................................................................... 71
5.2.2. H th ng MIMO-OFDM. ........................................................................ 72
5.2.3. Thông s kênh truy n. ............................................................................ 72
5.3. L u đ s đ thu t toán c a ch ng trình ph ng.ư ơ ươ ........................ 73
5.3.1. Truy n tín hi u. ....................................................................................... 73
5.3.2.nh truy n. ............................................................................................ 73
5.3.3. Nh n tín hi u. .......................................................................................... 74
5.3.4. Thu t toán tính BER. ............................................................................... 75
5.4. K t qu mô ph ng và đánh giá.ế .................................................................... 76
5.5. K t lu n ch ng.ế ươ ........................................................................................... 80
K T LU N VÀ H NG PT TRI N Đ TÀI. ƯỚ ............................................. 81
I LI U THAM KH O. .................................................................................... 82
PH L C.
Đ ÁN T T NGHI P.
THU T NG VI T T T.
THU T NG VI T T T.
A
AMPS Advance Mobile Phone Service
AWGN Addition White Gaussian Noise
B
BER Bit Error Rate
BLAST Bell labs Layered Space Time
C
CDMA Code Division Multiple Access
CP Cyclic Prefix
CNR Carrier Noise Rate
CSI Channel State Information
D
DFT Discrete Fourier Transform
E
EGC Equal Gain Combiner
F
FDMA Frequency Division Multiple Access
FEC Forward Error Correcting
FFT Fast Fourier Transform
G
GSM Global System For Mobile Communication
I
IS-95 Interim Standard 95
IS-136 Interim Standard 136
ISI InterSymbol Interference
ITU International Telecom Union
IDFT Inverse Discrete Fourier Transform
IFFT Inverse Fast Fourier Transform
Đ ÁN T T NGHI P.