Interference Cancellation and Detection for MAC with Two Users - Interference Cancellation Using Space-Time Processing and Precoding Design - page 8

Fig. 2.2 Flow chart for our
design

,,,

f (,,,)

f (,) (,) f

1 2

†

f (,)

f ()

f ()

n 1
n 2

,

where E s denotes the total transmit energy of each user and W 1

=

denote the noise at the receiver at time slots 1 and 2, respectively.
We assume that n 1 , n 2 ,

n 1
n 2

W 2

=

n 1 , n 2 are i.i.d complex Gaussian noises with mean 0 and

variance 1. If we let

h 11 h 12
h 21 h 22

h 11 a 11 +

h 12 a 21 h 11 a 12 + h 12 a 22

H 1

HA 1

= = = (2.8)

h 21 a 11 + h 22 a 21 h 21 a 12 + h 22 a 22

g 11 b 11 +

g 11 g 12 g 12 b 21 g 11 b 12 + g 12 b 22

G 1

GB 1 = = = (2.9)

g 21 g 22 g 21 b 11 + g 22 b 21 g 21 b 12 + g 22 b 22

h 11 h 12
h 21 h 22

h 11 a 11 + (2.10)

h 12 a 21 h 11 a 12 + h 12 a 22

H 2

HA 2 = = =

h 21 a 11 + h 22 a 21 h 21 a 12 + h 22 a 22

g 11 b 11 +

g 11 g 12 g 12 b 21 g 11 b 12 + g 12 b 22

G 2

GB 2

= = = (2.11)

g 21 g 22 g 21 b 11 + g 22 b 21 g 21 b 12 + g 22 b 22

then channel equations ( 4.8 ) and ( 4.9 ) can be written as
y 1
y 2

E s h 11 h 12

c 1
c 2

E s

s 1
s 2

n 1
n 2

g 11 g 12

= + + (2.12)

h 21 h 22

g 21 g 22

y 1
y 2

E s h 11 h 12

−

E s

− n 1

n 2

(2.13)

c 2
c 1

g 11 g 12 s 2

s 1

= + +

h 21 h 22

g 21 g 22