Ứng dụng kỹ thuật MIMO trong LTE

H
H


C
C


V
V
I
I


N
N


C
C


N
N
G
G


N
N
G

G
H
H




B
B


U
U


C
C
H
H


N
N
H
H


V
V
I

I


N
N


T
T
H
H


N
N
G
G










 
TT NGHII HC





M
M
I
I
M
M
O
O


t
t
r
r
o
o
n
n
g
g


L
L
T
T
E

E








:
:





S
S
i
i
n
n
h
h


v
v
i
i



n
n












L
L


p
p

:
:


D
D
0
0
8
8
V
V
T
T
5
5





:
:




0
0
8
8
2
2
1
1
0
0

1
1
0
0
2
2
6
6
3
3


K
K
h
h


a
a






:
:

2
2
0
0
0
0
8
8






2
2
0
0
1
1
3
3


H
H



:
:


C
C
h
h


n
n
h
h


q
q
u
u
y
y



/2012













 


N
 
 
 








10 12 12





 Trang i






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
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
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
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
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
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









- 


 Trang ii




 iv
 Error! Bookmark not defined.
Danh m Error! Bookmark not defined.
 vi
 1
1.1.  1
1.2.  2
1.3. n ca LTE 3
 4
 5
 6
1.4.  7
1.5.  8
1.5.1. Truyn d ph tn. 8
1.5.2.  9
1.5.3.  10
1.5.4.  11

2.1.  14
2.2.  14
2.3.  15
2.4.  16
2.4.1.     tp anten thu 16
2.4.2. S kt hp chn lc SC 17
2.4.3. S kt hp t l cc i MRC 19
2.4.4.  21
2.5.  24
2.5.1.  25
2.5.1.1. p tr 25

 Trang iii


2.5.1.2. p tr  26
2.5.1.3.  tp bng    gian- thi gian 27
2.5.1.4.  tp da     gian-tn s 28
2.5.2. nh d 29
ng dng MIMO trong LTE 33
3.1. Gii thi 33
3.2. u thc t 33
3.3.  m 35
3.3.1.  35
3.3.1.1. S  Alamouti hai anten  vi mt anten thu 35
3.3.2.  41
3.3.2.1. n 41
3.3.2.2.  k da  tin   45
3.4.  48
3.5.  50

3.5.1.  51
3.5.2. -MIMO 51
3.6.  53
3.6.1.  54
3.6.2.  55
3.7.  56
 58



 Trang iv




3GPP
Third Generation Partnership
Project

CQI
Channel Quality Indicator
Ch th cht lng knh
ZF
Zero Forcing
Cng bc 
MIMO
Multi Input Multi Output
u ra
SC-FDMA
Single Carrier Frequency Division

multiple Access
n
s 
SDMA
Spatial Division Multiple Access


WCDMA
Wideband Code Division
Multiple Access
a truy nhm
bng
FDMA
Frequency Division Multiple
Access
a truy nhtn
s
GPRS
General Packet Radio Services
Dch v yn  chung
OFDMA
Orthogonal Frequency Division
Multiplex
 kchia theo tn
s
trc giao
FDM
Frequency Division Multiplex
 kchia theo tn
s

OFDM
Orthogonal Frequency Division
Multiplex
 kchia theo tn
s trc giao
AMPS
Advanced Mobile Phone System
H thng in thoi di ng
 tin
GSM
Global System for Mobile
communications
H th
cu
UMTS
Universal Mobile
Telecommunications System
H thng ving
u
SC
Selective Combining
Kt hp la chon
BPSK
Binary Phase-Shift Keying
 dch pha nh 
STBC
Space-Time Block Coding
-thi gian
STTC
Space-Time Trelis Coding

-thi gian
UTRAN
Universal Terrestrial Radio
Access Network
Mng truy nhn mt
t ton cu
MU-MIMO
Multi User MIMO
MIMO a ng
SU-MIMO
Single User MIMO

SVD
Sigular Value Decomposition
 
STTD
Space-Time Transmit Diversity
-thi
gian
CDD
Cyclic Delay Diversity
 tp tr 
LTE
Long Term Evolution
 trin i hn
FDD
Frequence Division Duplexing
n s

 Trang v

TDD
Time Division Duplexing
i gian
UE
User Eqipment
Thit b 
SNR
Signal to Noise Ratio
T s 

HSUPA
High Speed Uplink Packet
Access
Truy nhp i tc  cao
ng 


 Trang vi














             
LTE. K thui thi u qu s dng ph.
M d thng phc t 
u s    d li
hiu qu s dng ph tt k thu thiu c




 


  k thut MIMO

 
 hiu v k thut MIMO   tp
 ghp knh  gian.  n tp trung   k thut c ng dng nhiu
nht trong h thng 4G LTE.

 Trang vii


c s  ch bo tu
c 
i s c gng, n lc ca b  i ni
c giao  m m vi nh 
h c chi nh

bn ch bn chnh sng n
trin tip theo.
  em trong
thi gian hc t t nghip.


c hin




 t nghip


 Trang 1



TE
1.1. Gi
 h th a chun. UMTS th
h th ba dc tri gi m b
cnh tranh cho h thu d m
c pn v  ng UMTS vi Long Term
u cao cho LTE, bao gm gim chi i bit
p dch v t dng linh hon hin
mng vp m  
th  thit b u cui. Lin minh Vin thg Quc t (ITU)  nh ngha truyn
tng di ng th h th 4  IMT Advanced v chia thnh hai h thng dg cho
di ng tc  cao v di ng tc  thp. 3GPP LTE  h thng dng cho di ng

tc  cao. Ngoi ra, y cn  cng ngh h thng ch hp u tin trn th gii
ng dng c chun 3GPP LTE v cc chun dch v ng dng khc, do  ngi s
dng c th d dng thc hin cuc gi hoc truyn d liu gia cc mng LTE
v c mng GSM/GPRS hoc UMTS da trn WCDMA. Kin trc mng mi
c thit k vi mc tiu cung cp lu lng chuyn mch gi vi dch v cht
lng,  tr ti thiu. H thng s dng bng thng linh hot nh vo m hnh a
truy cp OFDMA v SC-FDMA. Thm vo , FDD (Frequency Division
Duplexing) v TDD (Time Division Duplexing), bn song cg FDD cho php c
UE c g thnh thp. Khg ging nh FDD, bn
song cg FDD kng yu cu
pht v thu ti cg thi im. iu ny lm gim
g thnh cho b song cng trong
UE. Truy cp tuyn ln da vo a truy cp phn chia theo tn s n sng mang
(Single Carrier Frequency Division multiple Access SC-FDMA) cho php tng vng
ph tuyn ln lm t s cng sut nh trn cg sut trung bnh thp (Peak-to-
Average Power Ratio PAPR) so vi OFDMA. Thm vo ,  ci thin tc  d
liu nh, h thng LTE s dng hai n bn ln h s ph cell so vi h thng HSPA
Release 6.
 t nghip


 Trang 2


 : Cn th h tip theo  ci thin cc nc im ca 3G v
p ng nhu u ca ngi s dng; Ngi dg i i tc  d liu v cht lng
dch v cao hn; Ti u h thg chuyn mh gi; Tip tc nhu cu i hi ca
ngi ng v gim g thnh (CAPEX v OPEX); Gim  pc tp; Trnh s
phn on khng cn thit cho hot ng ca t cp hoc khg phi mt p di
thg.

 Bt u nm 2004, d n LTE tp trung
vo pht trin thm UTRAN v ti u u trc truy cp v tuyn a 3GPP. Mc tiu
hng n  dung lng d liu truyn ti trung bnh ca t ngi ng trn 1
MHz so vi mng HSDPA Rel. 6: Ti xu: p 3 n 4 ln (100Mbps). Ti ln: gp
2 n 3 ln (50Mbps). m 2007, LTE ca k thut truy cp v tuyn th h th 3 
EUTRA- pht trin t nhg c kh thi  a ra c c tnh k thut c chp
nhn. Cui nm 2008 cc k thut ny c s dng trong thng mi. Cc k thut
OFDMA c s dng cho ng xung v SC-FDMA c sdng cho ng ln.

1.2. 
Nhng hong ca 3GPP trong vic ci tin m
ng, nhng m

cc dn chng bn 3GPP TR 25.913.
Nh
c
 Ting
 Hiu sut h thng
  n khai
 Ki dch chuyn
 Qun
  phc tp
 Nhng v chung
 
 T nh tc thi vi xung: 100
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 Trang 3

Mbps.
 ng d liu truyn ta mi
mng HSDPA Rel.6:
Tn 3 ln.
Ti xung: gn 4 ln.
 Hong ti t di chuyn c-15 km/h. Vn hong tt
vi t t 15-120 km/h. Vc hon vi t
t 120-350 km/h (thn).

 m b 
trong phn 30km. T 30-n ch.
   hong vn 1.25Mhz, 1.6 Mhz,
 chiu xung. H tr c ng h 
ng bng nhau ho
 c m t nhit mi bt
n s trthut
 th ch
n IP (all- tr c hai ch  
1.3. bn ca LTE

-  2,6 GHz
- 


- 
- 15 MHz;


- -

-

 t nghip


 Trang 4


- 

-100 km

- 


UMTS.
- 


-
0 ms

- 






               

    -2000 (1.9   
 900 MHz,  




 lp va LTE


1.1

UL
DTFS-OFDM (SC-FDMA)
 t nghip


 Trang 5


DL
OFDMA

1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz,
20 MHz

1 ms

15 KHz







QPSK, 16QAM, 64QAM

1 

-



1
2
3
4
5
 

DL
10
50
100
150
300
UL
5
25
50
50

75


20 MHz

DL
QPSK, 16QAM, 64QAM
UL
QPSK, 16QAM
QPSK, 16QAM, 64QAM
Dch v ca LTE








 t nghip


 Trang 6




1.3






    


    

     


     
   
   

     


    



     


    


  
     


Games
     

  


   



 





cao.


    
    

      
    
     

 t nghip

 Trang 7


   


    


     





      
     

     
    
     


1.4. 
t t d ling xu
 ph 
b ph h d li t l u ki
th biu ding xung 
c tho lu tr c ch  i vng
hp TDD, truyn dng xu xut hin

ng thu t d lith ng thi.
M i vng ha LTE cho

ng thc t d linh theo ph
thuyt  u v  tr
 tr mt phu khi tr mt phi
 tr mt phu khi tr ca vic chuyn t tr
thit b u cung t b u
cu gn d linh th nht
c th hin qua thi gian chuyn tip t trng hn

 tc chinh th
c th hin qua thi gian
chuyn tip t tr chng h
Release 6 Cell- tc chim 50ms. Trong c hai th t tr
ch  ng hiu non-c loi tr. (Ch  
trt b u cu c nhn bi i vi mng truy nh
tuyng truy nht c thua thit b u
 t nghip


 Trang 8


cut b u cuc ch nh mt b
u cui   trong ch  ng  lng nghe h thng mng ti nhng khong
thi gian c th. Tr-t b u cui
c nhn bii vi mng truy nhn. Tuy mng truy nh
tuyn
bit thit b u cu trong t t b u cui li

c
ct c t b u cuth 
 ng).  tr mt phc th hin qua th truyn mt
IP nh t thit b u cui tc l lp IP. Thi
gian truyn theo mng s  i (unloaded
t thit b u cut hin trong t 
 mi v tr mt phu khi h tr t 200
thit b u cung  trong trc khi hong  khong tn 5Mhz.
Trong m rt b du cuc h tr. S
ng thit b u cuc trong t 
th .
1.5. 
1.5.1. Truyn d ph tn.
M s linh ca LTE-Advanced r  c tht
a phi b rn da so vi nhc
cung cp   rn dc
tho lun trong ni dung ca LTE - Advanced. Vic m r r c thc
hin trong khi v c b
s di kt t c kt
hp v cung c rn thii vi thit b u cui LTE,
mn s xut hit thit b
u cui LTE-   ri kt tp.
ng hp nhau m
u kit. Truy nhn mt
ng ln ph  c  b          -
 t nghip


 Trang 9

 t tn k  x 
t khng ln ph 
ng s kt tp ph n k c t nh thy,
mi kt tp ph c h tr bc t  kt tp ph 
c cung cp bt b u cui cp cao nht.
Cung truy nh rn d hu
 nh t  cho vic m r
c  s li

-0-1  v khi kt t
1.5.2. 
 nh d
 then cht vc chn s tip tt vai
 LTE-Advanced. Thit k n ti cung c
n bn cng anten vu tham chi th ng  ng xung, kt
hp vi s ti p c s 
n bn ln t nh d
(da tr t hp v r 
n ti s c t t xa so vu ca
LTE- thc rng h tr 
s t phn ca LTE-Advanced. Vi lp truyn dng xut xa
con s b  c s dn b i vi s 
 t nghip


 Trang 10


t m rn.

1.5.3. 
M t s liu ca LTE-u s ci thi v t l 
hiu SNR  thit b u cunh d
ng hin ti, nhiu anten n mt nn m x 
c s dng nhi hiu qu v n khai
m phi hp v c  m  
2.  ng xu ra s phi hp truyn dn t m truyn dn. Ph thuc
 rn
 t b u cun ra s truyn dn xu nhim
t v mt v   d  b thu cho truyn
dm. M d c sng truyn ti, quyt
nh t m truyn d truyn thit b c th. Bt b u cui
n bic s hin din ca truyn du tham chiu UE
c th (s a LTE) phc s dng cho vi
thit ln dm phi hp cung c l  mng
t qu i thin b khut  mc bit 
i trng nh   khut  tri.


 t nghip


 Trang 11


1.2: Truyn dm phi hp
 t b u cui cung cn hi trn
mng cho tt c ng xung hin th i vi mt thit b u cui ri
  thu vn gin dm.  ng, b

tt c  m trong m thc hin phi hng
truyn dng  m truyn d thc hin tin l
hiu truy n mt thit b  gim can nhiu gia nhng
i s dng. Loi truyn dm phi h cung ci
  c ci thi mnh u
mong mui hp can nhiu gia nhi s d ci thin
a SNR. Bt b u cun bit vic x  m
cu tham chiu UE c th.
 
git b u cuc cung cn bit truyn dn phi hp
 nh mnh truyn d
th c s dng cho vic x u c  t b u cui.
 m phi hng x 
 b thu.  nhi n, v dng
trong nhiu h thng mng t n nay.
1.5.4. 
T vi ng truyn, vic trin ti
nhau nhm gim kho s
li ln s khu c.
c c lc chuy
t b u cu ng b ly
n th i vi c thit b u cum g 
c lp cao cn tip L1), chng h 
u khit truyn ca b lp, chng hn, ch c b li s
dng hin din trong khu vu khin bi b lp nh s liu
 t nghip


 Trang 12

cung cp trong khu vc b sung t t b u cu
ng dn m lc
bu khin dp bing nm  trm gc
 lp ng trong sut t ng.

 gi li
chuyn tii s dc phc vn tip
gi--truyn ti i s liu thu
o ra tr    
chuyn tin ti   c thc hin
m cho mi kt ni.
i v lp, tn ti nhi thu
c h tr (chng hn, h tr c nhy, h tr c mc
 t hai tc truyn tic thc hin  lp 2
(chuyn tip lp 2) hay lp 3 (chuyn tip lp 3 hoc t chuyn tip (self backhauling))
Mng nhau  nhin (chng hn tri ti
u bc hoc giao din m
chua bn t d 
chu thu


 1-3. Chuyn tip trong LTE-Advanced
1.6. Tng k
 t nghip


 Trang 13

Kng quan v LTE. Nhu
Ting; Hiu sut h thng;  
n khai; Ki dch chuyn; Qu
ct s   xu l
chuyn tip; truyn dm phi hp; k thun d
r ph t 
 chng truyn dc m
nh d then cht
vc chn s tip t LTE-
Advanced.

 t nghip


 Trang 14




2.1. 
K thuc truy thut s dng nhiu anten
 truyn d liu. t k thui mi quan trng
cc s d ci thin hiu sut ca h thng. K thui
thi u qu s dng ph. M d
thng phc t   u s 
th  d liu qu s dng ph t
mt k thu thiu ca LTE.


2.2. 

Mt trong nhng c  quan trng trong cu  a anten  khong 
gia hai phn t anten do khong   anten  mi quan h vi  tng quan
gia fading kyn c nh bi  hiu ti c anten  nhau). 
anten c t xa nhau   tng quan fading thp. Ngc li,  anten
c t gn nhau   tng quan fading cao, bn cht   anten  nhau
s fading tc thi tng t nhau.
Khong  thc t cn thit gia  anten   tng quan cao/ thp ph
thuc vo bc  ng ng  tn s  mang c s dng. Tuy 
ng ph thuc  kch bn khi trin khai. ng hp  anten trm gc,
i tng macro-cell (tc   ln  v tr anten trm gc phi cao), khong
cen  khong 10 bc   mi m bo  tng quan thp, trong
khi  khong  anten cho m u cui di ng khong na bc 
  nhau gia trm gc vi m u cui di ng  do trong kch bn
macro, phn x a ng gy ra fading ch yu xut hin  nhng  gn
xung quanh m u cui di ng. Do  khi  t v tr m u cui  ta
 t nghip


 Trang 15


thy  nhng ng khc nhau i n trong mt c ln,  tng quan vn s
thp vi kho anten tg ng nh.    v  trm gc, nhng
ng  nhau s n trong mt  nh h nhiu, nn  ch anten
phi  ln   tng quan thp.
Trong kch bn trin khai khc, v d trin khai kch bn micro-cell vi anten
trm gc thp h irng trm gy
ging vi mi trng m u cui h cho nn khong c gia  anten
trm gc s nh h vn m bo  tng quan thp.
 anten gi thit  n c ng phn cc. Mt    t c 

tng quan fading thp l p dng  cc  nhau i vi anten  nhau.
Khi  anteh c t gn nhau.
2.3. 
c minh ha



  tt nghii hc


 Trang 16


Ma trc biu di








 








 



  















(2.1)

h
nm
 l  m.

1
, x
2


Nt
]
T

y = [y
1
, y
2

Nt
]
T

 = [
1
, 
2

Nt
]
T
ng phc c
 hin v.
 ginh bi biu
thc sau:



















 







 



  

























  








 (2.2)

 th vit li quan h 
 (2.3)
2.4. 
K thut a anten c s dng ph bin nht trong lch s v  phc tp
nht  k thut  anten thu. N tng c gi l n tp thu hoc phn tp Rx
mc dg phi lmch ca k thut ng ln t chng li
fading   tuyn.
2.4.1.     tp anten thu
Trong m  knh fadinh  1 anten   N
r
anten thu, ma trn knh
au:
H = [h
1
,h
2
h
Nr
] (2.4)
Trong  h
m
  li ca ng truyn t anten  n m thu m vi
m=N
r
.