MIMO (multiple input multiple output) :
- / () (beamforming),
- .
MIMO . MIMO : Nt , Nr . . 3.19.
. 3.19. MIMO
, (.3.19),
y = H × x + n (3.6)
n . H:
(3.7)
hij i j . . hij , . . LTE MIMO , eNB UE . .
/ (- ), (- ) . - (Space Time Coding STC). 2×1 (.3.20) 1 2 S1 S2 - S* 2 :
1 | 2 | |
t = 0 | s1 | s2 |
t = 1 | -s2* | s1* |
. 3.20. STC 2×1
t = 0 t = 1 :
r(0) = h1s1 + h2s2 + n(0) (3.8)
r(1) = -h1s2* + h2s1* + n(1),
n(0) n(1) ().
s1 s2 :
y1 = h1*r(0) + h2r*(1) = (|h1|2 + |h2|2)s1 + h1*n(0) + h2n*(1) (3.9)
y2 = h2*r(0) - h1r*(1) = (|h1|2 + |h2|2)s2 + h2*n(0) h1n*(1)
, /
(3.10)
(R = 1).
LTE , (layers). MIMO (precoding) , , 4. (rank) . . 3.21.
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. 3.21.
LTE 2 : (SCW single codeword) (MCW multiple codewords). CRC (check redundancy code), , . (layer mapping) MIMO .
. , . - . , MMSE-SIC (Minimum Mean Square Error Successive Interference Cancellation), . MMSE-SIC . 3.22. , . , MIMO .
. 3.22. MMSE-SIC
2-3 UMTS, CDMA2000, LTE WiMAX. : , , ( Home NodeB) , .
(. 10.1)
- (Macrocell). 500 ‒ 1500 . , .
- (Microcell). 300 ‒ 500. . ( - -, , , . .).
- (Picocell). 100 ‒ 300. , , , (, . .).
- (Femtocell). 20 ‒ 50. , (, ).
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. 10.1.
. (femtocell) ‒ , ( 20 ). , , - (. 10.2).
.10.2.
.10.2 UMTS . NodeB, Home NodeB ( HNB), . . HNB, / , . , HSPA [1].
, HNB. , . , (Mobility Management), , . HNB , . . HNB . , (, , ) . . , . , , . HNB 5 30 . UMTS (Home NodeB) LTE (Home eNodeB) [25].
20 HNB [26]. (Femtocell Access Point Management System).